Mid-Infrared Research Papers - Academia.edu (original) (raw)

In the field of FTIR spectroscopy, the far infrared (FIR) spectral region has been so far less investigated than the mid-infrared (MIR), even though it presents great advantages in the characterization of those inorganic compounds, which are inactive in the MIR, such as some art pigments, corrosion products, etc. Furthermore, FIR spectroscopy is complementary to Raman spectroscopy if the fluorescence effects caused by the latter analytical technique are considered. In this paper, ATR in the FIR region is proposed as an alternative method to transmission for the analyses of pigments. This methodology was selected in order to reduce the sample amount needed for analysis, which is a must when examining cultural heritage materials. A selection of pigments have been analyzed in both ATR and transmission mode, and the resulting spectra were compared with each other. To better perform this comparison, an evaluation of the possible effect induced by the thermal treatment needed for the preparation of the polyethylene pellets on the transmission spectra of the samples has been carried out. Therefore, pigments have been analyzed in ATR mode before and after heating them at the same temperature employed for the polyethylene pellet preparation. The results showed that while the heating treatment causes only small changes in the intensity of some bands, the ATR spectra were characterized by differences in both intensity and band shifts towards lower frequencies if compared with those recorded in transmission mode. All pigments' transmission and ATR spectra are presented and discussed, and the ATR method was validated on a real case study.

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- Engineering, Cultural Heritage, FTIR spectroscopy, Raman Spectroscopy

Mid-infrared laser diodes with an active region consisting of five ''W'' InAsSb/InAsP/InAsSb/ InAsPSb quantum wells and broad InAsPSb waveguide were fabricated by metalorganic vapor phase epitaxy on InAs substrates. Laser emission was demonstrated at 3.3 m up to 135 K from asymmetrical structures having n-type InAsPSb and p-type InPSb cladding layers. The devices operated in pulsed regime at 3.3 m, with a lowest threshold current density of 120 A/cm 2 at 90 K, and an output power efficiency of 31 mW/facet/A. The characteristic temperature was 35 K.

- by P. Christol
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- Engineering, Applied Physics, Organic Semiconductor Laser, Physical sciences

The feasibility of utilizing infrared spectroscopy for the prediction of haze formation in white wines resulting from heat and colloidal stability tests was investigated. One-hundred eleven white wines, representing multiple regions and varieties from the 2008 California vintage, were collected and analyzed. The near and mid-infrared spectra were measured and heat and colloidal (ethanol addition) stability tests were performed on the same wines. Partial-least squares regression analysis was then used to construct models predictive of the resulting nepholometric turbidity to the acquired spectra. Preliminary models obtained following application of spectral pretreatments today considered as ''classical'' (e.g., derivatives, standard normal variate, vector normalization, constant offset elimination) lacked robustness; two alternative algorithms designed to remove spectral information unrelated to the turbidity were then employed (orthogonal signal correction; direct orthogonal signal correction). While OSC pretreatment did not result in more robust models, DOSC considerably enhanced the goodness of the PLS model constructed to predict the ethanol test turbidity. Predictive modeling of the short-NIR spectra, following DOSC preprocessing, allowed the prediction of colloidal stability on an unknown test set with an R 2 = 0.80 and a RMSEP = 10.12 using three latent variables. When the data set was restricted to Chardonnay wines alone, the predictive ability improved, with R 2 = 0.85 and RMSEP = 8.90.

- by Andrea Versari
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- Chemistry, Food Engineering, Food, Prediction

We present a model of a dusty disk with an inner hole which accounts for the Spitzer Space Telescope Infrared Spectrograph observations of the low-mass pre-main sequence star CoKu Tau/4. We have modeled the mid-IR spectrum (between 8 and 25 µm) as arising from the inner wall of a disk. Our model disk has an evacuated inner zone of radius ∼ 10 AU, with a dusty inner "wall", of half-height ∼ 2 AU, that is illuminated at normal incidence by the central star. The radiative equilibrium temperature decreases from the inner disk edge outward through the optically-thick disk; this temperature gradient is responsible for the emission of the silicate bands at 10 and 20 µm. The observed spectrum is consistent with being produced by Fe-Mg amorphous glassy olivine and/or pyroxene, with no evidence of a crystalline component. The mid-infrared spectrum of CoKu Tau/4 is reminiscent of that of the much older star TW Hya, where it has been suggested that the significant clearing of its inner disk is due to planet formation. However, no inner disk remains in CoKu Tau/4, consistent with the star being a weak-emission (non-accreting) T Tauri star. The relative youth of CoKu Tau/4 (∼ 1 Myr) may indicate much more rapid planet formation than typically assumed.

- by William Forrest
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- Organic Chemistry, Astrophysical Plasma, Protoplanetary Disks, Astrophysics

Both visible near-infrared (VNIR) and mid-infrared (MIR) spectroscopy have been claimed to better predict pesticide sorption in soils than other methods. We compared the performances of VNIR and MIR spectroscopy for predicting both organic carbon content (f OC ) and the sorption affinity (K d ) of diuron in 112 surface soils from South Australia. Separate calibration models were developed between VNIR and MIR spectra, and f OC and K d using partial least-squares (PLS) regression. MIR clearly outperformed VNIR for predictions of both f OC and K d in soils. Correlation (R 2 ) and accuracy (RPD) indices were 0.4 and 1.3 for the VNIR-PLS model versus 0.8 and 2.3 for the MIR-PLS model, respectively, for K d prediction. PLS loadings for sorption prediction were compared in terms of the soil information they contained. While VNIR loading did not include any direct spectral information regarding soil minerals, MIR loading included peaks associated with sand, clays, and carbonates. Perhaps by better predicting f OC and integrating the effects of OC as well as minerals, the MIR-PLS model provided a better prediction for diuron K d values in our calibration set.

- by Ronald Smernik
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- Soil, Spectroscopy, Modeling, Prediction

We report first results of laboratory tests of Si:As blocked-impurity-band (BIB) mid-infrared (4 to 28 µm) detectors developed by IMEC. These prototypes feature 88 pixels hybridized on an integrated cryogenic readout electronics (CRE). They were developed as part of a technology demonstration program for the future Darwin mission. In order to be able to separate detector and readout effects, a custom build TIA circuitry was used to characterize additional single pixel detectors. We used a newly designed test setup at the MPIA to determine the relative spectral response, the quantum efficiency, and the dark current. All these properties were measured as a function of operating temperature and detector bias. In addition the effects of ionizing radiation on the detector were studied. For determining the relative spectral response we used a dualgrating monochromator and a bolometer with known response that was operated in parallel to the Si:As detectors. The quantum efficiency was measured by using a custom-build high-precision vacuum black body together with cold (T ∼ 4 K) filters of known (measured) transmission.

- by Patrick Merken
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- Performance, Astronomy, Radiation Detectors, Quantum Efficiency

Selecting the correct dimensionality is critical for obtaining partial least squares (PLS) regression models with good predictive ability. Although calibration and validation sets are best established using experimental designs, industrial laboratories cannot afford such an approach. Typically, samples are collected in an (formally) undesigned way, spread over time and their measurements are included in routine measurement processes. This makes it hard to evaluate PLS model dimensionality. In this paper, classical criteria (leave-one-out cross-validation and adjusted Wold's criterion) are compared to recently proposed alternatives (smoothed PLS-PoLiSh and a randomization test) to seek out the optimum dimensionality of PLS models. Kerosene (jet fuel) samples were measured by attenuated total reflectance-mid-IR spectrometry and their spectra where used to predict eight important properties determined using reference methods that are time-consuming and prone to analytical errors. The alternative methods were shown to give reliable dimensionality predictions when compared to external validation. By contrast, the simpler methods seemed to be largely affected by the largest changes in the modeling capabilities of the first components. (J.M. Andrade).

- by Douglas Rutledge
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- Analytical Chemistry, Experimental Design, Software, Calibration

Crop protection seldom takes into account soil heterogeneity at the field scale. Yet, variable site characteristics affect the incidence of pests as well as the efficacy and fate of pesticides in soil. This article reviews crucial starting points for incorporating soil information into precision crop protection (PCP). At present, the lack of adequate field maps is a major drawback. Conventional soil analyses are too expensive to capture soil heterogeneity at the field scale with the required spatial resolution. Therefore, we discuss alternative procedures exemplified by our own results concerning (i) minimally and noninvasive sensor techniques for the estimation of soil properties, (ii) the evidence of soil heterogeneity with respect to PCP, and (iii) current possibilities for incorporation of high resolution soil information into crop protection decisions. Soil organic carbon (SOC) and soil texture are extremely interesting for PCP. Their determination with minimally invasive techniques requires the sampling of soils, because the sensors must be used in the laboratory. However, this technique delivers precise information at low cost. We accurately determined SOC in the near-infrared. In the mid-infrared, texture and lime content were also exactly quantified. Non-invasive sensors require less effort. The airborne HyMap sensor was suitable for the detection of variability in SOC at high resolution, thus promising further progress regarding SOC data acquisition from bare soil. The apparent electrical conductivity as measured by an EM38 sensor was shown to be a suitable proxy for soil texture and layering. A survey of arable fields near Bonn (Germany) revealed widespread within-field heterogeneity of texture-related ECa, SOC and other characteristics. Maps of herbicide sorption and application rate were derived from sensor data,

- by Gerhard Welp
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- Environmental Science, Precision Agriculture, NIRS, Near Infrared

We discuss the effect of atmospheric dispersion on the performance of a mid-infrared adaptive optics assisted instrument on an extremely large telescope (ELT). Dispersion and atmospheric chromaticity is generally considered to be negligible in this wavelength regime. It is shown here, however, that with the much-reduced diffraction limit size on an ELT and the need for diffraction-limited performance, refractivity phenomena should be carefully considered in the design and operation of such an instrument. We include an overview of the theory of refractivity, and the influence of infrared resonances caused by the presence of water vapour and other constituents in the atmosphere. 'Traditional' atmospheric dispersion is likely to cause a loss of Strehl only at the shortest wavelengths (L-band). A more likely source of error is the difference in wavelengths at which the wavefront is sensed and corrected, leading to pointing offsets between wavefront sensor and science instrument that evolve with time over a long exposure. Infrared radiation is also subject to additional turbulence caused by the presence of water vapour in the atmosphere not seen by visible wavefront sensors, whose effect is poorly understood. We make use of information obtained at radio wavelengths to make a first-order estimate of its effect on the performance of a mid-IR ground-based instrument. The calculations in this paper are performed using parameters from two different sites, one 'standard good site' and one 'high and dry site' to illustrate the importance of the choice of site for an ELT.

- by Stefan Hippler
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- Water, Turbulence, Adaptive Optics, Dispersion

Deep extragalactic surveys with ISOCAM revealed the presence of a large density of faint mid-infrared (MIR) sources. We have computed the 15 µm integrated galaxy light produced by these galaxies above a sensitivity limit of 50 µJy. It sets a lower limit to the 15 µm extragalactic background light of (2.4 ± 0.5) nW m −2 sr −1. The redshift distribution of the ISOCAM galaxies is inferred from the spectroscopically complete sample of galaxies in the Hubble Deep Field North (HDFN). It peaks around z ∼ 0.8 in agreement with studies in other fields. The rest-frame 15 µm and bolometric infrared (8-1000 µm) luminosities of ISOCAM galaxies are computed using the correlations that we establish between the 6.75, 12, 15 µm and infrared (IR) luminosities of local galaxies. The resulting IR luminosities were double-checked using radio (1.4 GHz) flux densities from the ultra-deep VLA and WSRT surveys of the HDFN on a sample of 24 galaxies as well as on a sample of 109 local galaxies in common between ISOCAM and the NRAO VLA Sky Survey (NVSS). This comparison shows for the first time that MIR and radio luminosities correlate up to z ∼ 1. This result validates the bolometric IR luminosities derived from MIR luminosities unless both the radio-far infrared (FIR) and the MIR-FIR correlations become invalid around z ∼ 1. The fraction of IR light produced by active nuclei was computed from the cross-correlation with the deepest X-ray surveys from the Chandra and XMM-Newton observatories in the HDFN and Lockman Hole respectively. We find that at most 20% of the 15 µm integrated galaxy light is due to active galactic nuclei (AGNs) unless a large population of AGNs was missed by Chandra and XMM-Newton. About 75% of the ISOCAM galaxies are found to belong to the class of luminous infrared galaxies (LIR ≥ 10 11 L). They exhibit star formation rates of the order of ∼100 M yr −1. The comoving density of infrared light due to these luminous IR galaxies was more than 40 times larger at z ∼ 1 than today. The contribution of ISOCAM galaxies to the peak of the cosmic infrared background (CIRB) at 140 µm was computed from the MIR-FIR correlations for star forming galaxies and from the spectral energy distribution of the Seyfert 2, NGC 1068, for AGNs. We find that the galaxies unveiled by ISOCAM surveys are responsible for the bulk of the CIRB, i.e. (16 ± 5) nW m −2 sr −1 as compared to the (25 ± 7) nW m −2 sr −1 measured with the COBE satellite, with less than 10% due to AGNs. Since the CIRB contains most of the light radiated over the history of star formation in the universe, this means that a large fraction of present-day stars must have formed during a dusty starburst event similar to those revealed by ISOCAM.

The potential of noninvasive determination of glucose, lactic acid, and nisin in Lactococcus lactis subsp. lactis biofilm fermentation was investigated through fourier transform mid-infrared (FTIR) spectroscopy. Samples obtained from a biofilm bioreactor were analyzed with traditional methods and FTIR spectroscopy. The FTIR spectra were interpreted by using suitable spectra wavenumber regions through multivariate statistical techniques such as partial least square (PLS) and principal component regression (PCR). The standard error of calibration for the PLS-1 st derivative calibration models for glucose, lactic acid, and nisin were 3.87 g/l, 2.62 g/l, and 189.6 IU/ml, respectively. Prediction errors were low for glucose and lactic acid, whereas nisin could be reliably quantified when its concentration is higher than 800 IU/ml. Results indicated that FTIR spectroscopy could be used for rapid detection of glucose and lactic acid concentrations, and nisin activity in nisin fermentation.

- by Ali Demirci
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- Raman Spectroscopy, Near Infrared, Near Infrared Spectroscopy, Prediction error
- by Sandra Torriani and +1
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- Principal Component Analysis, Vibrational Spectroscopy, Saccharomyces cerevisiae, Wine Yeast

Currently, the authentication of virgin coconut oil (VCO) has become very important due to the possible adulteration of VCO with cheaper plant oils such as corn (CO) and sunflower (SFO) oils. Methods involving Fourier transform mid infrared (FT-MIR) spectroscopy combined with chemometrics techniques (partial least square (PLS) and discriminant analysis (DA)) were developed for quantification and classification of CO and SFO in VCO. MIR spectra of oil samples were recorded at frequency regions of 4000-650 cm À1 on horizontal attenuated total reflectance (HATR) attachment of FTIR. DA can successfully classify VCO and that adulterated with CO and SFO using 10 principal components. Furthermore, PLS model correlates the actual and FTIR estimated values of oil adulterants (CO and SFO) with coefficient of determination (R 2 ) of 0.999.

We present results of ultra-deep ISOCAM observations through a cluster-lens at 7µm and 15µm with the Infrared Space Observatory (ISO) satellite. These observations reveal a large number of luminous Mid-Infrared (MIR) sources. Cross-identification in the optical and Near-Infrared (NIR) wavebands shows that about half of the 7 µm sources are cluster galaxies. The other 7 µm and almost all 15 µm sources are identified as lensed distant galaxies. Thanks to the gravitational amplification they constitute the faintest MIR detected sources, allowing us to extend the number counts in both the 7 and 15 µm bands. In particular, we find that the 15 µm counts have a steep slope α 15µm = −1.5 ± 0.3 and are large, with N 15µm (> 30µJy) = 13 ± 5 arcmin −2 . These numbers rule out non-evolutionary models and favour very strong evolution. Down to our counts limit, we found that the resolved 7 µm and 15 µm background radiation intensity is respectively (2±0.5)×10 −9 and (5±1)×10 −9 W m −2 sr −1 .

Total phenolic content (TPC) and total antioxidant capacity (TAC) of four onion varieties (red, white, yellow and sweet) and shallot from selected locations (Washington, Idaho, Oregon, Texas and Georgia) were determined using Fourier transform infrared (FT-IR) spectroscopy (4000-400 cm À1 ). The Folin-Ciocalteu (F-C) assay was used to quantify TPC and three assays were used to determine TAC, including 2,2-diphenyl-picrylhydrazyl (DPPH) assay, Trolox equivalent antioxidant capacity (TEAC) assay and ferric reducing antioxidant power (FRAP) assay. Partial least squares regression (PLSR) with cross-validation (leave-oneout) was conducted on onion and shallot extracts (n = 200) and their corresponding F-C, DPPH, TEAC and FRAP values were employed to obtain four independent calibration models for predicting TPC and TAC for the extracts. Spectra from an extra 19 independent extracts were used as an external validation set for prediction. A correlation of r > 0.95 was obtained between FT-IR predicted and reference values (by F-C, DPPH, TEAC and FRAP assay) with standard errors of calibration (SEC) and standard errors of cross-validation (SECV) less than 2.85, 0.35 and 0.45 lmol Trolox/g FW of extracts for TEAC, FRAP and DPPH assay, respectively; and 0.36 mg gallic acid/g FW of extracts for the F-C assay. In addition, cluster analysis (principal component analysis (PCA)) and discriminant function analysis (DFA) could differentiate varieties of onions and shallot based upon infrared spectral features. Loading plots for the various chemometrics models indicated that hydroxyl and phenolic functional groups were most closely correlated with antioxidant capacity. The use of mid-infrared spectroscopy to predict the total antioxidant capacity of vegetables provides a rapid and precise alternative to traditional wet chemistry analysis.

- by Barbara Rasco
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- Engineering, Principal Component Analysis, Food Chemistry, Multidisciplinary

- by Luca Laghi
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- Food Engineering, Food, Prediction, Stability

We report a new study of the nucleus of Comet 2P/Encke, which the CONTOUR spacecraft is scheduled to encounter in November 2003. During the comet's close approach to Earth in July 1997, we measured the mid-infrared thermal and optical scattered continua with data from the TIMMI instrument (imaging) at the ESO 3.6-m telescope (wavelength λ from 8 to 12 µm), the ISOPHOT instrument (photometry) aboard ISO (3.6 µm ≤ λ ≤ 100 µm), and the STIS instrument (imaging) aboard HST (5500Å ≤ λ ≤ 11000Å ). The optical images show the nucleus with very little coma contamination, and the ISO photometry allowed us to separate the comatic and nuclear contributions to the ESO images. We used the Standard Thermal Model for slow rotators to calculate an effective nuclear radius of 2.4 km ± 0.3 km. The comet's mid-IR light curve implies a nuclear rotation period of 15.2 h ± 0.3 h, although some subharmonics of this also satisfy the data. If we assume that the nucleus is a triaxial ellipsoid in principal short axis rotation with the axis direction in 1985 as derived by Sekanina (1988, Astron. J. 95, 911), then by combining our data with light curves from the 1980s we find that the nucleus' angular momentum vector migrates, making a would-be circle in less than 81 years, and that one axial ratio is at least 2.6. The nucleus' optical linear phase coefficient is 0.06 mag/degree, making it one of the most phasedarkened objects known. The surface is also rougher than that of 146 FERNÁNDEZ ET AL. most asteroids. The visual geometric albedo is 0.05 ± 0.02, within the range found for other cometary nuclei. c 2000 Academic Press Key Words: comets; infrared observations. 12 µm. The images have 64 2 pixels and cover (21.8 ) 2 . Each pixel width covered 65 to 87 km at the comet during the observing run. The plate scale was measured using the known relative positions of α Cen A and B . The pointspread function's (PSF) full width at half-maximum (FWHM) varied from 0.7 to 1.0 arcsec. Chopping of the secondary mirror northward and nodding of the telescope westward, with typical throws of 30 arcsec, were employed. An array flat field was created by measuring the relative photometry of a bright star at 23 different locations on the array and then interpolating a surface with a minimum of curvature. We observed the comet at three wavelengths, but only at λ = 10.7 µm was the comet bright enough to let us build a well-sampled time series of data. Absolute flux calibration was done using α Cen A, whose 10.7-µm magnitude is −1.56 ± 0.05, interpolating from photometric data given by . The magnitude scale zero point is 35.7 Jy. Color corrections were done and were at most

- by Carey M Lisse
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- Geochemistry, Geophysics, Optical Imaging, Mid-Infrared

This work has demonstrated in situ mid-infrared (mid-IR) monitoring with the ReactIR/DiComp probe to be a powerful technique for real-time analysis of catalytic three-phase processes. The usefulness of FTIR/ATR spectroscopy to resolve dilemmas about reaction mechanisms and providing reliable kinetic data by means of chemometric analysis of a series of mid-IR spectra taken during the reaction course was successfully shown on an example of Pd/C catalyzed enantioselective hydrogenation of prochiral, exocyclic ␣,␤-unsaturated ketones, using (S)-proline as a chiral auxiliary in various solvents. The intermediate formed by the chemical interaction between an ␣,␤-unsaturated ketone and (S)-proline, which was supposed previously to confirm the proposed asymmetric synthesis approach, was not evidenced by the performed investigation to the detection limit of 0.2 mmol/l.

- by Albin Pintar
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- Chemical Engineering, FTIR spectroscopy, Asymmetric Synthesis, Real Time

Fusion of radar and EO-sensors for the purpose of surveillance is investigated. All sensors are considered to be co-located with respect to the distance of the area under surveillance. More specifically, the applicability for such multi-sensor systems is examined for surveillance in littoral waters. The sensor suite is a coherent polarimetric radar in combination with a set of camera's sensitive in visible light, near infrared, mid infrared and far infrared. A so-called fuse while track algorithm is the best candidate for these dissimilar colocated and not necessarily synchronized sensors.

- by Arne Theil
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- Polarimetry, Synchronization, Near Infrared, Algorithm
- by M. Remennyy
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- Carbon Dioxide, Vibrational Spectroscopy, Methane, Mid-Infrared

Impacts of boreal forest fires have absorbed intensive attention because of huge fires in these years in Alaska as well as Siberia. To reduce impacts of forest fire in boreal forest area, the early fire detection is one of essential components in firefighting activity because of difficulties of fire suppressing in remote area without water. Here, we developed fire detection information system from receiving AVHRR to output fire detection map and validated the early detection algorithm using AVHRR satellite imagery. Forest fires were detected using an algorithm; two-dimensional histogram method by Prof. Kudo. This algorithm uses a threshold on mid-infrared band 3 and a two-dimensional histogram of visible band 1 and thermal infrared band 5 as a looking up table; these detection criteria corresponds becoming to burnt to black, thermal emission by burning. As a ground truth data, we collected reports of fires observed by local firefighters in Siberia and reports of JAL passenger flights. We compared satellite detected pixels with location of reported fires. We aggregated this comparison by fires to estimate the fire detection rate and early fire detection rate. We found the fire detection rate was surprisingly different between fires reported by firefighters and by passenger flights. Finally, we found the reason of the different fire detection rate as scale of fires observed. This implies difficulty on forest fire detection especially for small sized forest fires, and also implies the importance of ground truth data especially reported by fire fighters. We are planning extend the area collecting ground truth data delivered from local firefighting agencies in Alaska and Siberia from this summer season to validate the forest fire detection algorithms using AVHRR and MODIS. As a preparation, we made a system to detect forest fires every day automatically for area of entire Alaska last summer.

- by Hiroshi Tani
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- Forest fire, Seasonality, Look up Table, Boreal Forest

Infrared spectroscopy and Raman spectroscopy provide complementary technologies for rapid and precise detection of microorganisms and are emerging methods in food analysis. It is possible to use either of these techniques to differentiate and quantify microorganisms in relatively simple matrices such as liquid media and simple solutions with determinations taking less than an hour. Vibrational spectroscopy, unlike other techniques used in microbiology, is a relatively simple method for studying structural changes occurring within a microbial cell following environmental stress and applications of food processing treatments. Vibrational spectroscopy provides a wide range of biochemical properties about bacteria in a single spectrum, most importantly characteristics of the cell membrane. These techniques are especially useful for studying properties of bacterial biofilms on contact surfaces, the presence and viability of bacterial vegetative cells and spores, the type and degree of bacterial injury, and assessment of antibiotic susceptibility. Future trends in food analysis will involve combining vibrational spectroscopy with microscopy, mass spectroscopy, or DNA-based meth-ods to comprehensively study bacterial stress. Further advances in selectivity, sensitivity, and improved chemometric methods, along with reduction in the cost of instrumentation, may lead to the development of fieldready and real-time analytical systems.

- by Mengshi Lin
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- Microbiology, Raman Spectroscopy, Vibrational Spectroscopy, Food Processing

The presence of lard or its derivatives in any food products is a serious religious issue among Muslim and Judaism. Thus, the objective of this study was to investigate the use of gas chromatography with flame ionisation detector (GC-FID) coupled with chemometrics techniques such as Principle Components Analysis (PCA) and K-mean cluster analysis to differentiate lard adulteration at very low concentrations in beef and chicken fats. The measurements w ere made from the pure lard, beef tallow, pure chicken fat; and beef tallow (BT), chicken fat (CF) adulterated with different concentrations of lard (0.5%-10% in BT and CF). The data were first scaled into standardisation before PCA is performed to each of the scaled data using Unscrambler software. The Scores plots and loadings plots of each scaled data were compared and studied. The results showed that lard contains higher fatty acid (FA) of C18: 2cis and low C16:0 FA, but oppositely for beef tallow and chicken fat. The amount of C4:0, C14:0, and C18:0 FAs are approximately similar for all fats. Others FAs are small in amount and nearly similar for both. Additionally, PCA was able to significantly identify lard, beef fat, chicken fat an d the mixtures of lard and beef tallow, lard and chicken fat, even at lower concentration level (0.5 % lard-99.5% beef tallow / chicken fat (w/w). K-mean cluster only able to classify the pure lard (LD), pure chicken fat (CF) and pure bee f tallow (BT).

The 3.3 micron PAH feature is undetected for the majority of the sample (97%), with typical upper limits of 5E-16 W/m^2. Compact 11.2 micron PAH emission is seen directly towards 1 out of the 53 Spitzer Short-High spectra, for a source that is borderline embedded. For all 12 sources with both VLT and Spitzer spectra, no PAH features are detected in either. In total, PAH features are detected toward at most 1 out of 63 (candidate) embedded protostars (<~ 2%), even lower than observed for class II T Tauri stars with disks (11-14%). Assuming typical class I stellar and envelope parameters, the absence of PAHs emission is most likely explained by the absence of emitting carriers through a PAH abundance at least an order of magnitude lower than in molecular clouds but similar to that found in disks. Thus, most PAHs likely enter the protoplanetary disks frozen out in icy layers on dust grains and/or in coagulated form.

- by Fred Lahuis
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- Star Formation, Dust (Astronomy & Astrophysics), Molecular Clouds, Planetary Systems

Electron injection dynamics in dye sensitized TiO 2 nanocrystalline thin lms are studied with femtosecond mid-infrared spectroscopy. Three classes of sensitizer molecules, Ru(dcbpy) 2 (X) 2 (X 2 D 2SCN, 2CN, and dcbpy), Fe(dcbpy) 2 (CN) 2 , and ReCl(CO) 3 (dcbpy), are used to examine the dependence of injection rate and yield on the excited state redox potentials. We observed that electron injection occurred on the <100 fs time-scale and injection quantum yield depended on the redox potential for the series of Ru dyes. These results suggest that electron injection to TiO 2 competes with electronic and vibrational relaxation within the sensitizer excited states and the branching ratio between these two processes determines the injection quantum yield for sensitizer molecules with an excited state redox potential below the conduction band-edge.

- by Hirendra Ghosh
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- Thin Film, Mid-Infrared, Excited states, Quantum Yield

The modern poultry industry is not satisfied with the traditional system of the handling and processing of eggs which is based on candling and visual inspection of the eggs. Currently, the operator of the conveyer does not have the opportunity to inspect 120 000 eggs per hour and to estimate the freshness, weight, bacterial infection, presence of technical spoilage, eggshell

- by Bart Ketelaere and +1
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- Fluorescence Spectroscopy, Industrial Biotechnology, Near Infrared, Mid-Infrared

The vast majority of gaseous chemical substances exhibit fundamental vibrational absorption bands in the mid-infrared spectral region (≈ 2-25 µm), and the absorption of light by these fundamental bands provides a nearly universal means for their detection. A main feature of optical techniques is the non-intrusive in situ detection capability for trace gases. The focus time period of this chapter is the years 1996-2002 and we will discuss primarily CW mid-infrared laser spectroscopy. We shall not attempt to review the large number of diverse mid-infrared spectroscopic laser applications published to date. The scope of this chapter is rather to discuss recent developments of mid-infrared laser sources, with emphasis on established and new spectroscopic techniques and their applications for sensitive, selective, and quantitative trace gas detection. For example, laboratory based spectroscopic studies and chemical kinetics, which will also benefit from new laser source and technique developments, will not be considered.

- by Frank Tittel
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- Laser Spectroscopy, Chemical Kinetics, Mid-Infrared, Spectroscopic Techniques
- by Romdhane Karoui
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- Food Microbiology, Food Analysis, Multivariate Analysis, Mid-Infrared

Ultrabroadband infrared transition metal ion-doped solid-state lasers have come of age and are increasingly being used in trace gas monitoring, remote sensing, telecommunications, ophthalmology, and neurosurgery. Operating at room temperature, they are stable, versatile, and easy to handle successors to the color center lasers. They are becoming the critical components in optical frequency standards, space-based remote sensing systems, and may soon find application in femtochemistry and attosecond science.

- by Evgeni Sorokin
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- Quantum Physics, Remote Sensing, Near Infrared, Solid State Laser

Altitude profiles of ClONO 2 retrieved with the IMK (Institut für Meteorologie und Klimaforschung) science-oriented data processor from MIPAS/Envisat (Michelson Interferometer for Passive Atmospheric Sounding on Envisat) mid-infrared limb emission measurements between July 2002 and March 2004 have been validated by comparison with balloon-borne (Mark IV, FIRS2, MIPAS-B), airborne (MIPAS-STR), ground-based (Spitsbergen, Thule, Kiruna, Harestua, Jungfraujoch, Izaña, Wollongong, Lauder)

- by Michael Hannigan
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- Atmospheric Science, Atmospheric sciences, Error Analysis, Mid-Infrared

Chalcogenide or heavy metal oxide glasses are well known for their good transparency in the mid-infrared (MIR) domain as well as their high nonlinear refractive index (n 2 ) tens to hundreds times higher than that of silica. We have investigated the nonlinear frequency conversion processes, based upon either stimulated Raman scattering (SRS) or soliton fission and soliton self-frequency shift (SSFS) in fibres made up with such highly nonlinear infrared transmitting glasses. First, SRS has been investigated in a chalcogenide As 2 S 3 step index fibre. In the single pass configuration, under quasi continuous wave 1550 nm pumping, Raman cascade up to the forth Stokes order has been obtained in a 3 m long piece of fibre. The possibility to build a Raman laser thanks to in-fibre written Bragg gratings has also been investigated. A 5 dB Bragg grating has been written successfully in the core. Then, nonlinear frequency conversion in ultra-short pulse regime has been studied in a heavy metal oxide (lead-bismuth-gallium ternary system) glass photonic crystal fibre. Broadband radiation, from 800 nm up to 2.8 µm, has been obtained by pumping an 8 cm long piece of fibre at 1600 nm in sub-picosecond pulsed regime. The nonlinear frequency conversion process was assessed by numerical modelling taking into account the actual fibre cross-section as well as the measured linear and nonlinear parameters and was found to be due to soliton fission and Raman-induced SSFS. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 09/17/2014 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 7714 77140B-2 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 09/17/2014 Terms of Use: http://spiedl.org/terms

- by Ryszard Buczynski
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- Nonlinear Optics, Numerical Modelling, Near Infrared, Photonic Crystal Fibre

In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H 3 PO 4 ), citric acid (C 6 H 8 O 7 ) and H 2 O 2 , followed by chemical polishing with the sodium hypochlorite (NaClO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current-voltage measurements. The zero-bias resistance area product R 0 A above 4 × 10 5 cm 2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air.

- by P. Christol
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- Materials Engineering, Condensed Matter Physics, Mid-Infrared, Sodium Hypochlorite

- by J. Mellqvist
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- Atmospheric Science, Atmospheric sciences, Error Analysis, Mid-Infrared

There is an increasing demand of the consumers and actors of the food industry sector to have means of measurement allowing the characterisation of raw materials or food. Dairy products (milk, ice cream, yogurt, butter, cheese, etc.) are in considerable demand, command premium prices and are, therefore, vulnerable to economic adulteration. Authenticity of these products is an important issue for food processors, retailers, regulatory authorities and consumers. It is also valuable for ensuring fair competition and as a mean of protecting consumers against fraud due to mislabelling. Conventional chemical methods are not able to determine the regional provenance of dairy products unambiguously. Therefore, alternative techniques such as spectroscopic techniques i.e., near infrared (NIR), mid infrared (MIR), front face fluorescence spectroscopy (FFFS), stable isotope and nuclear magnetic resonance (NMR)-coupled with chemometric tools have many potential advantages as tools for the evaluation of the identity of such products. This review article discusses the potential of destructive and non-destructive techniques for the determination of the quality and the authenticity of dairy products.

Following an introduction to the history of the invention of the quantum cascade (QC) laser and of the band-structure engineering advances that have led to laser action over most of the mid-infrared (IR) and part of the far-IR spectrum, the paper provides a comprehensive review of recent developments that will likely enable important advances in areas such as optical communications, ultrahigh resolution spectroscopy and applications to ultrahigh sensitivity gas-sensing systems. We discuss the experimental observation of the remarkably different frequency response of QC lasers compared to diode lasers, i.e., the absence of relaxation oscillations, their high-speed digital modulation, and results on mid-IR optical wireless communication links, which demonstrate the possibility of reliably transmitting complex multimedia data streams. Ultrashort pulse generation by gain switching and active and passive modelocking is subsequently discussed. Recent data on the linewidth of free-running QC lasers ( 150 kHz) and their frequency stabilization down to 10 kHz are presented. Experiments on the relative frequency stability ( 5 Hz) of two QC lasers locked to optical cavities are discussed. Finally, developments in metallic waveguides with surface plasmon modes, which have enabled extension of the operating wavelength to the far IR are reported. I N THIS paper, we concentrate on reviewing recent developments in quantum cascade (QC) laser research in the areas of high-speed modulation, optical wireless, ultrashort pulse and Manuscript

- by Rainer Martini
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- Quantum Cascade Lasers, Band Structure, Digital Modulation, IEEE

Diffuse reflectance spectroscopy (DRS) is attracting much interest in the soil science community because it has a number of advantages over conventional methods of soil analyses. The techniques are more rapid, timely, cheaper and hence more efficient at obtaining the data when a large number of samples and analysis are required. Moreover, a single spectrum may be used to assess various physical, chemical and biological soil properties. Until now, research in soil spectroscopy has focused on spectral calibration and prediction of soil properties using multivariate statistics. In this paper we show how these predictions may be used in an inference system to predict other important and functional soil properties using pedotransfer functions (PTFs). Thus we propose the use of soil spectral calibration and its predictions as input and as a complement to a soil inference system (SPEC-SINFERS). We demonstrate the implementation of SPEC-SINFERS with two examples. As a first step, soil mid-infrared (MIR) spectra and partial least squares (PLS) regression are used to estimate soil pH, clay, silt, sand, organic carbon content and cation exchange capacity. A bootstrap method is used to determine the uncertainties of these predictions. These predictions and their uncertainties are then used as input into the inference system, where established PTFs are used to infer (i) soil water content and (ii) soil pH buffering capacity together with their uncertainties. An important feature of SPEC-SINFERS is the propagation of both input and model uncertainties.

- by Budiman Minasny
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- Soil Science, Science Communication, Multivariate Statistics, Prediction

Recent advances in the development of sensors based on infrared diode and quantum cascade lasers for the detection of trace gas species is reported. Several examples of applications in environmental and industrial process monitoring as well as in medical diagnostics using quartz enhanced photoacoustic spectroscopy and laser absorption spectroscopy will be described. Keywords: Trace gas detection, near infrared diode lasers, mid infrared quantum and interband cascade lasers, quartz enhanced photoacoustic spectroscopy, laser absorption spectroscopy.

NOx and HOx production in the upper atmosphere caused by geomagnetic phenomena such as EPP (Energetic particles precipitation), under the appropriate meteorological conditions may descent within the polar vortex. Such phenomenon can modify substantially the NOy budget of upper stratosphere and participate in catalytic processes controlling ozone of polar regions. However, the inclusion in existing stratospheric models of ionic or

- by Yves Rochon
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- Mid-Infrared, Spectrum, Ozone, Ozone layer depletion

In this paper, a multi-technique in-situ non-invasive approach has been followed for the study of the materials used for a painting by Pierre-Auguste Renoir, “A woman at her toilette”. The study was carried out using five portable spectroscopic techniques, namely X-ray fluorescence, mid-infrared reflectance spectroscopy, near infrared reflectance spectroscopy, and UV-Vis spectroscopy in absorption and emission. The painting was selected as a case study because it was examined in advance of the current investigation using conventional micro-sampling techniques. This provided the opportunity to evaluate potential and limitations of the non-invasive approach to the complex case of the modern painting.

- by Costanza Miliani
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- Condensed Matter Physics, Comparative Study, Case Study, UV/Vis spectroscopy

We present 5 to 15 µm Spitzer Infrared Spectrograph (IRS) low resolution spectral data of a candidate debris disk around an M4.5 star identified as a likely member of the ∼40 Myr old cluster NGC 2547. The IRS spectrum shows a silicate emission feature, indicating the presence of warm, small, (sub)micron-sized dust grains in the disk. Of the fifteen previously known candidate debris disks around M-type stars, the one we discuss in this paper is the first to have an observed mid-infrared spectrum and is also the first to have measured silicate emission. We combined the IRS data with ancillary data (optical, JHK s , and Spitzer InfraRed Array Camera and 24 µm data) to build the spectral energy distribution (SED) of the source. Monte Carlo radiation transfer modeling of the SED characterized the dust disk as being very flat (h 100 =2 AU) and extending inward within at least 0.13 AU of the central star. Our analysis shows that the disk is collisionally dominated and is likely a debris disk.

- by Paula Teixeira
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- Organic Chemistry, Astrophysical Plasma, Monte Carlo, Mid-Infrared

ABSTRACT Using an FTIR-based photo-modulated transmission spectroscopic technique a red-shift in bandgap has been observed at room temperature for an InSb1-xNx ternary alloy, relative to binary InSb, and determined to be approximately... more

- by Jeff Hosea
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- Transition-Metal Oxides, Nitrogen, Mid-Infrared, Fourier transform

Cotton always has trash associated with its fibers, which is known to affect processing effi- ciency. Rotor spinning is more sensitive to trash levels in cotton compared with ring spinning, the other major spinning system. Trash trapped in the rotor grove is typically pulverized cotton fiber and trash particles whose origins cannot be visu- ally determined (e.g. leaf, fiber, bark, seed coat, etc.). New techniques or instruments are neces- sary to reliably provide rapid, consistent, and quantitative identification of cotton trash sources. The goal of this research was to identify the ori- gins and to understand the impact of each type of pulverized substance on textile processing. Re- search has been done with infrared microscopy in order to confirm the utility of infrared mapping of cotton biological components. The mid-infrared region is between the wave numbers 4000 and 650 cm -1 and can be evaluated with Fourier-transform infrared (FT-IR) as a qualitative and quantitative analyti...

- by David McAlister
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- Seed Coat, Mid-Infrared, Infrared, Fourier transform infrared

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the ENVISAT satellite provides profiles of temperature and various trace-gases from limb-viewing mid-infrared emission measurements. The stratospheric nitric acid (HNO 3 ) from September 2002 to March 2004 was retrieved from the MIPAS observations using the science-oriented data processor developed at the Institut für Meteorologie und Klimaforschung (IMK), which is complemented by the component of non-local thermodynamic equilibrium (non-LTE) treatment from the Instituto de Astrofísica de Andalucía (IAA). The IMK-IAA research product, different from the ESA operational product, is validated in this paper by comparison with a number of reference data sets. Individual HNO 3 profiles of the IMK-IAA MI-PAS show good agreement with those of the balloon-borne version of MIPAS (MIPAS-B) and the infrared spectrometer MkIV, with small differences of less than 0.5 ppbv throughout the entire altitude range up to about 38 km, and below 0.2 ppbv above 30 km. However, the degree of consistency is largely affected by their temporal and spatial coincidence, and differences of 1 to 2 ppbv may be observed between 22 and 26 km at high latitudes near the vortex boundary, due to large horizontal inhomogeneity of HNO 3 . Statistical comparisons of MIPAS IMK-IAA HNO 3 VMRs with respect Correspondence to: D. Y. Wang (dwang@unb.ca) to those of satellite measurements of Odin/SMR, ILAS-II, ACE-FTS, as well as the MIPAS ESA product show good consistency. The mean differences are generally ±0.5 ppbv and standard deviations of the differences are of 0.5 to 1.5 ppbv. The maximum differences are 2.0 ppbv around 20 to 25 km. This gives confidence in the general reliability of MIPAS HNO 3 VMR data and the other three satellite data sets.

- by Michael Gunson
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- Atmospheric Science, Atmospheric sciences, Standard Deviation, Reference Data

In the short space of 15 years since their first demonstration, quantum cascade lasers have become the most useful sources of tunable mid-infrared laser radiation. This Letter describes these developments in laser technology and the burgeoning applications of quantum cascade lasers to infrared spectroscopy. We foresee the potential application of quantum cascade lasers in other areas of chemical physics such as research on helium droplets, in population pumping, and in matrix isolation infrared photochemistry.

- by Frank Tittel
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- Technology, Chemical Physics, Infrared spectroscopy, Physical sciences

Forensic soil science represents a newly-developed discipline of soil science, and has matured to the extent that well-defined questions and successful crime scene investigations can be answered in increasingly refined ways. This chapter considers two case studies and highlights the kinds of investigations that have been carried out on complex soil materials from shoes, vehicles and crime scenes by the Centre for Australian Forensic Soil Science (CAFSS). The two case examples are described in ways that show parallel approaches to more recent types of case investigations where soils as evidence are being applied with more certainty in criminal and environmental investigations. The history of forensic soil science and the importance of pedology and soil mineralogy are also briefly reviewed from a world perspective. The significance and relevance of established concepts and standard terminologies used in soil science but especially in pedology with practical relevance to forensic science are discussed. The systematic forensic soil examination approach described in this paper uses soil morphology (e.g. colour, consistency, texture and structure), mineralogy (X-ray powder diffraction) and chemistry (e.g. based primarily upon mid-infrared spectroscopy/diffuse reflectance infrared Fourier transform (DRIFT) analyses). Forensic soil characterisation usually combines the descriptive and analytical steps for rapid characterisation of whole soil samples for screening, and detailed characterisation and quantification of composite and individual soil particles after sample selection, size fractionation and detailed mineralogical and organic matter analyses using advanced analytical methods. X-ray powder diffraction methods are arguably the most significant for both qualitative and quantitative analyses of solid materials in forensic soil science. The two crime scene examples described in this paper use combined pedological (including field investigations), mineralogical and spectroscopic methods in the forensic comparison of small amounts of soil adhering to a suspect's shoe and carpet in a vehicle boot with control soil specimens. These case examples illustrate that forensic soil examination can be very complex because of the vast diversity and K. Ritz et al. (eds.), Criminal and Environmental Soil Forensics 105

- by Rob Fitzpatrick
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- Forensic Science, Case Study, Mid-Infrared, Sample Selection

We report on recent progress on external cavity diode lasers (ECDL) using a new concept of a Littman/Metcalf configuration. Within this concept one facet of the diode laser chip is used for coupling to a high quality Littman/Metcalf resonator whereas the other side of the diode laser chip emits the output beam. The alignment of the external resonator is independent from the alignment of the output beam and there is no need for any compromise in the alignment. This results in an improved behavior of the external resonator with the benefit of a drastic increase in power and single mode tuning.

This paper analytically describes the concept of enhancing the bandwidth of second-harmonic generation in the mid-infrared region in an isotropic tapered semiconductor slab configuration. In this slab geometry, the lengths between successive reflection points due to total internal reflection of the incident laser radiation increase when it propagates through the slab. A computer aided simulation has been carried out to determine the possibility of generating broadband second harmonic intensity for broadband fundamental laser radiations as they are allowed to undergo total internal reflection inside the tapered isotropic semiconductor crystal slab made of either gallium arsenide (GaAs) or zinc selenide (ZnSe). The simulated results indicate wide 3 dB bandwidths of 187 nm and 196 nm in a 30 mm long tapered slab of GaAs and ZnSe respectively. The conversion efficiency, after considering the absorption and reflection losses, is quite satisfactory (≈ 1%). The effects of variations in temperature, incident angle of the fundamental laser radiations at the air-slab interface, length and tapering angle of the semiconductor slab have been studied for generated second harmonic radiations in both GaAs and ZnSe crystals. Optimising these parameters a wider broadband frequency converter with appreciable conversion efficiency can be designed.

- by ardhendu saha
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- Second Harmonic Generation, Zinc, Mid-Infrared, Optical physics

We report the continuous-wave operation of an optically pumped mid-infrared (mid-IR) vertical-cavity surfaceemitting laser (VCSEL). The active region consisting of type-II antimonide quantum wells with a "W" configuration occupies a cavity formed by a semiconductor bottom mirror and dielectric top mirror. The emission wavelength of 2.9 m is nearly independent of temperature (d=dT 0.09 nm/K) compared to type-II edge-emitters and the multimode linewidth is narrow (2.9 nm). At T = 78 K, the threshold pump intensity is 940 W/cm 2 , the peak output power from a 50-m spot is 45 mW, and the differential power conversion efficiency is 4.5%. Lasing is observed up to T = 160 K.

Synchrotron-based Fourier-transform infrared (SR-FTIR) micro-spectroscopy was used to determine the concentration-dependent response of the organic structure of live cyanobacterial cells to silicification. Mid-infrared (4000 -600 cm Ϫ1 ) measurements carried out on single filaments and sheaths of the cyanobacteria Calothrix sp. (strain KC97) were used to monitor the interaction between a polymerizing silica solution and the organic functional groups of the cells during progressive silicification. Spectra of whole-cells and sheaths were analyzed and the spectral features were assigned to specific functional groups related to the cell: lipids (-CH 2 and -CH 3 ; at 2870 -2960 cm Ϫ1 ), fatty acids (ϾCϭO at 1740 cm Ϫ1 ), proteins (amides I and II at 1650 and 1540 cm Ϫ1 ), nucleic acids (ϾPϭO 1240 cm Ϫ1 ), carboxylic acids (C-O at 1392 cm Ϫ1 ), and polysaccharides (C-O between 1165 and 1030 cm Ϫ1 ). These vibrations and the characteristic vibrations for silica (Si-O between 1190 and 1060 cm Ϫ1 ; to some extent overlapping with the C-O frequencies of polysaccharides and Si-O at 800 cm Ϫ1 ) were used to follow the progress of silicification. Relative to unsilicified samples, the intensity of the combined C-O/Si-O vibration band increased considerably over the course of the silicification (whole-cells by Ͼ 90% and sheath by ϳ75%). This increase is a consequence of (1) extensive growth of the sheath in response to the silicification, and (2) the formation of thin amorphous silica layers on the sheath. The formation of a silica specific band (ϳ800 cm Ϫ1 ) indicates, however, that the precipitation of amorphous silica is controlled by the dehydroxylation of abiotically formed silanol groups.

- by Kurt Konhauser and +1
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- Geology, Geochemistry, Silica, Mid-Infrared