Total Internal Reflection Research Papers (original) (raw)
A new multi-modal biometric authentication approach using gait signals and fingerprint images as biometric traits is proposed. The individual comparison scores derived from the gait and fingers are normalized using four methods (min-max,... more
A new multi-modal biometric authentication approach using gait signals and fingerprint images as biometric traits is proposed. The individual comparison scores derived from the gait and fingers are normalized using four methods (min-max, z-score, median absolute deviation, tangent hyperbolic) and then four fusion approaches (simple sum, user-weighting, maximum score and minimum core) are applied. Gait samples are obtained by using a dedicated accelerometer sensor attached to the hip. The proposed method is evaluated using 7200 fingerprint images and gait samples. Fingerprints are collected by a capacitive line sensor, an optical sensor with total internal reflection and a touch-less optical sensor. The fusion results of these two biometrics show an improved performance and a large step closer for user authentication on mobile devices.
The Ca 2+ microdomains generated around the mouth of open ion channels represent the basic building blocks from which cytosolic Ca 2+ signals are constructed. Recent improvements in optical imaging techniques now allow these microdomains... more
The Ca 2+ microdomains generated around the mouth of open ion channels represent the basic building blocks from which cytosolic Ca 2+ signals are constructed. Recent improvements in optical imaging techniques now allow these microdomains to be visualized as single channel calcium fluorescence transients (SCCaFTs), providing information about channel properties that was previously accessible only by electrophysiological patch-clamp recordings. We review recent advances in single channel Ca 2+ imaging methodologies, with emphasis on total internal reflection fluorescence microscopy (TIRFM) as the technique of choice for recording SCCaFTs from voltage- and ligand-gated plasmalemmal ion channels. This technique of ‘optical patch-clamp recording ’ is massively parallel, permitting simultaneous imaging of hundreds of channels; provides millisecond resolution of gating kinetics together with sub-micron spatial resolution of channel locations; and is applicable to diverse families of membra...
Setiap kombinasi 2 material, selalu ada batas diantaranya. Sudut kritis adalah sudut datangnya cahaya menuju batas 2 medium yang menghasilkan sudut bias = 90° (terhadap garis normal), artinya cahaya terbiaskan sejajar permukaan batas.... more
Setiap kombinasi 2 material, selalu ada batas diantaranya. Sudut kritis adalah sudut datangnya cahaya menuju batas 2 medium yang menghasilkan sudut bias = 90° (terhadap garis normal), artinya cahaya terbiaskan sejajar permukaan batas. Jika sudut datangnya cahaya lebih besar dari pada sudut kritis, maka semua cahaya yang datang sepenuhnya dipantulkan oleh bidang batas. Kondisi ini disebut dengan pantulan internal total (total internal reflection). Sudut bias hanya akan membesar (menjauhi garis normal) jika cahaya bergerak dari medium yang lebih rapat menuju medium yang lebih renggang , sehingga kondisi total internal reflection hanya terbatas pada cahaya yang merambat dari medium rapat menuju medium renggang. Keadaan total internal reflection ini banyak diterapkan di kehidupan sehari-hari kita, salah satunya dalam pembuatan berlian. Berlian memiliki indeks bias = 2,417 , sedangkan indeks bias udara = 1,0003. Kita dapat menentukan sudut kritis berlian terhadap udara : Θcrit = sine-1 (n2 / n1) = sine-1 (nu / nb) Θcrit = sine-1 (1,0003 / 2,417) Θcrit = sine-1 (0.4659059152) = 27.76886709° Sudur kritis cahaya di batas berlian dan udara sangat kecil , sehingga cahaya yang masuk ke dalam berlian terperangkap di dalam berlian dan berkali-kali mengalami refleksi internal total dulu sebelum akhirnya dibiaskan ke udara. Hal ini membuat berlian seakan akan memancarkan cahaya dari dalam. Kombinasi dari pantulan cahaya langsung dan biasan cahaya dari refleksi internal tersebut membuat berlian tampak sangat berkilau. Efek kilau berlian juga dipengaruhi oleh bentuk berlian. Bentuk pahatan berlian mempengaruhi tingkat kilauan berlian. Para ahli pahat berlian membentuk sedemikian rupa
This paper describes an imaging microscopic technique based on heterodyne digital holography where subwavelength-sized gold colloids can be imaged in cell environments. Surface cellular receptors of 3T3 mouse fibroblasts are labeled with... more
This paper describes an imaging microscopic technique based on heterodyne digital holography where subwavelength-sized gold colloids can be imaged in cell environments. Surface cellular receptors of 3T3 mouse fibroblasts are labeled with 40 nm gold nanoparticles, and the ...
We have fabricated and characterized GaN LED devices whose mesa sidewalls are intentionally made deep and angled. The angled sidewalls efficiently deflect the photons guided laterally along the GaN epitaxial (epi) layer to a direction... more
We have fabricated and characterized GaN LED devices whose mesa sidewalls are intentionally made deep and angled. The angled sidewalls efficiently deflect the photons guided laterally along the GaN epitaxial (epi) layer to a direction normal to the surface via total internal reflection. Regardless of the sidewall angle, the sidewall-deflector-integrated (SDI) LEDs exhibit significant enhancement in the light output from
In this paper, we propose a novel sensor structure based on the rectangular ring resonator with the photonic crystal microcavity (PCM), and optimize the structure using finite-difference time-domain (FDTD) method. This sensor consists of... more
In this paper, we propose a novel sensor structure based on the rectangular ring resonator with the photonic crystal microcavity (PCM), and optimize the structure using finite-difference time-domain (FDTD) method. This sensor consists of the rectangular resonator with total internal reflection mirror and the PCM, which can be placed at the nearby optical waveguide of the rectangular ring resonator. The PCM is composed of a defect cavity with different holes on the center of it. The Q-factor of the PCM can be significantly enhanced when the PCM has the resonance wavelength. The PCM can be evanescently coupled to a side waveguide arm of the rectangular ring resonator. The sensitivity of the ring resonator in the presence of gas or biomolecules composition was calculated using the FDTD method. When the injected gas or biomolecules pass through the PCM, the variation of effective index due to their concentration affects the resonance condition of the rectangular ring resonator. We have investigated how the shift of the resonance peak in the resonance wavelengths depends on the gas or biomolecules concentration. We also have optimized the sensor structure for the waveguide width and length, the hole radius, and the number of hole on the PCM. The optimum lattice constants, hole radius, and cavity length are 370, 100, and 580 nm, respectively. The rectangular ring resonator sensor with microcavity significantly enhances the quality factor and the sensitivity compared to the directional coupler sensor with PCM. The change of normalized output power in rectangular ring resonator with PCM is approximately twice larger than the change in directional coupler with PCM.
The vibrational spectra of LiPF6 1M solutions formed in aprotic mixed solventsobtained by mixing ethylene carbonate with dimethyl carbonate and diethylcarbonate are discussed. The Raman and infrared spectra of lithium... more
The vibrational spectra of LiPF6 1M solutions formed in aprotic mixed solventsobtained by mixing ethylene carbonate with dimethyl carbonate and diethylcarbonate are discussed. The Raman and infrared spectra of lithium hexafluorophosphate(LiPF6) and the quantum chemical computations of the vibrationalwavenumbers and intensities are reported. Due to the nature of the solutions,attenuated total internal reflectance spectroscopy was used to obtain the infraredspectra.
Total Internal Reflection Photoacoustic Spectroscopy (TIRPAS) is a method that exploits the evanescent field of a nanosecond duration laser pulse reflecting off a glass/water interface to generate photoacoustic responses. These... more
Total Internal Reflection Photoacoustic Spectroscopy (TIRPAS) is a method that exploits the evanescent field of a nanosecond duration laser pulse reflecting off a glass/water interface to generate photoacoustic responses. These photoacoustic events are generated in light absorbing analytes suspended in the fluid medium in contact with the glass that are within the penetration depth of the evanescent wave. This method has been employed in previous studies by Hinoue et al. Hinoue et al. used an optically chopped HeNe laser at 632.8 nm to detect Brilliant Blue FCF dye at different angles of incidence. In recent years, the advent of high power nanosecond pulsed tunable lasers has allowed for the re-visitation of the TIRPAS idea under stress confinement and orders of magnitude larger peak energy conditions. Compared to conventional detection methods, this approach has the potential to detect much smaller quantities of disease indicators, such as circulating tumor cells and hemazoin crystals in malaria, than other optical methods. The detection limit of the TIRPAS system was quantified using chlorazol black solution with an absorption coefficient of 55 cm-1 at 532 nm. Interaction with the evanescent field was verified by varying the angle of incidence of the probe laser beam that generated the photoacoustic waves, thereby changing the penetration depth of the evanescent field as well as the photoacoustic spectroscopy effect from angled excitation.