Kenneth Järrendahl | Linköping University (original) (raw)
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Papers by Kenneth Järrendahl
Nanomaterials
Transparent films of cellulose nanocrystals (CNC) are prepared by dip-coating on glass substrates... more Transparent films of cellulose nanocrystals (CNC) are prepared by dip-coating on glass substrates from aqueous suspensions of hydrolyzed filter paper. Dragging forces acting during films’ deposition promote a preferential alignment of the rod-shaped CNC. Films that are 2.8 and 6.0 µm in thickness show retardance effects, as evidenced by placing them between a linearly polarized light source and a linear polarizer sheet in the extinction configuration. Transmission Mueller matrix spectroscopic ellipsometry measurements at normal incidence as a function of sample rotation were used to characterize polarization properties. A differential decomposition of the Mueller matrix reveals linear birefringence as the unique polarization parameter. These results show a promising way for obtaining CNC birefringent films by a simple and controllable method.
Applied Surface Science, 2002
The current–voltage (I–V) and capacitance–voltage (C–V) behaviour of different Si/Ge multilayers ... more The current–voltage (I–V) and capacitance–voltage (C–V) behaviour of different Si/Ge multilayers and SiGe single layers prepared on p-type Si substrates by magnetron sputtering and annealing, has been studied in the temperature range of 80–320K by using Al Schottky contacts as test structures. Although a significant influence of the microstructure of the Si/Ge multilayers and SiGe layers was obtained on the
Journal of Applied Physics, 2000
Spectral Mueller matrices measured at multiple angles of incidence as well as Mueller matrix imag... more Spectral Mueller matrices measured at multiple angles of incidence as well as Mueller matrix images are recorded on the exoskeletons (cuticles) of the scarab beetles Cetonia aurata and Chrysina argenteola. Cetonia aurata is green whereas Chrysina argenteola is gold-colored. When illuminated with natural (unpolarized) light, both species reflect left-handed and near-circularly polarized light originating from helicoidal structures in their cuticles. These structures are referred to as circular Bragg reflectors. For both species the Mueller matrices are found to be nondiagonal depolarizers. The matrices are Cloude decomposed to a sum of non-depolarizing matrices and it is found that the cuticle optical response, in a first approximation can be described as a sum of Mueller matrices from an ideal mirror and an ideal circular polarizer with relative weights determined by the eigenvalues of the covariance matrices of the measured Mueller matrices. The spectral and image decompositions are consistent with each other. A regression-based decomposition of the spectral and image Mueller matrices is also presented whereby the basic optical components are assumed to be a mirror and a circular polarizer as suggested by the Cloude decomposition. The advantage with a regression decomposition compared to a Cloude decomposition is its better stability as the matrices in the decomposition are determined a priori. The origin of the depolarizing features are discussed but from present data it is not possible to conclude whether the two major components, the mirror and the circular polarizer are laterally separated in domains in the cuticle or if the depolarization originates from the intrinsic properties of the helicoidal structure.
Philosophical Magazine, 2012
Thin Solid Films, Nov 28, 2014
Thin Solid Films, Nov 28, 2014
Nano letters, Nov 26, 2014
Chirality, tailored by external morphology and internal composition, has been realized by control... more Chirality, tailored by external morphology and internal composition, has been realized by controlled curved-lattice epitaxial growth of InxAl1-xN nanospirals. The curved morphology of the spiral segments is a result of a lateral compositional gradient while maintaining a preferred crystallographic growth direction, implying a lateral gradient in optical properties. Individual nanospirals show an asymmetric core-shell structure with curved basal planes. Mueller matrix spectroscopic ellipsometry shows that the tailored chirality is manifested in the polarization state of light reflected off the nanospirals.
Optical Materials Express, Nov 5, 2014
Optical Materials Express, Jun 19, 2014
Materials Today: Proceedings, 2014
Thin Solid Films, Nov 28, 2014
Springer Series in Surface Sciences, 2014
ABSTRACT A brief description of the polarizing environment we are living in and the possibilities... more ABSTRACT A brief description of the polarizing environment we are living in and the possibilities for some animals to detect this polarization is made. This is followed by a presentation of how animals and plants generate polarized light, usually through reflection from micro- and nanostructures. Special attention is made to scarab beetles reflecting light with a high degree of circular polarization. Finally some comments on the biological aspects of polarization are made.
Thin Solid Films, Nov 28, 2014
Optics express, Jan 31, 2012
We studied the far-field optical response of supported gold-silica-gold nanosandwiches using spec... more We studied the far-field optical response of supported gold-silica-gold nanosandwiches using spectroscopic ellipsometry, reflectance and transmittance measurements. Although transmittance data clearly shows that the gold nanodisks in the sandwich structure interact very weakly, oblique reflectance spectra of s- and p-polarized light show clearly asymmetric line-shapes of the Fano type. However, all experimental results are very well described by modeling the gold nanodisks as oblate spheroids and by employing a 2 × 2 scattering matrix formulation of the Fresnel coefficients provided by an island film theory. In particular, the Fano asymmetry can be explained in terms of interference between the scattered waves from the decoupled nanodisks in the spectral range limited by their respective plasmon resonances. We also show that the reflectance and ellipsometry spectra can be described by a three-layer system with uniaxial effective dielectric functions.
Philosophical Magazine, 2012
Nanomaterials
Transparent films of cellulose nanocrystals (CNC) are prepared by dip-coating on glass substrates... more Transparent films of cellulose nanocrystals (CNC) are prepared by dip-coating on glass substrates from aqueous suspensions of hydrolyzed filter paper. Dragging forces acting during films’ deposition promote a preferential alignment of the rod-shaped CNC. Films that are 2.8 and 6.0 µm in thickness show retardance effects, as evidenced by placing them between a linearly polarized light source and a linear polarizer sheet in the extinction configuration. Transmission Mueller matrix spectroscopic ellipsometry measurements at normal incidence as a function of sample rotation were used to characterize polarization properties. A differential decomposition of the Mueller matrix reveals linear birefringence as the unique polarization parameter. These results show a promising way for obtaining CNC birefringent films by a simple and controllable method.
Applied Surface Science, 2002
The current–voltage (I–V) and capacitance–voltage (C–V) behaviour of different Si/Ge multilayers ... more The current–voltage (I–V) and capacitance–voltage (C–V) behaviour of different Si/Ge multilayers and SiGe single layers prepared on p-type Si substrates by magnetron sputtering and annealing, has been studied in the temperature range of 80–320K by using Al Schottky contacts as test structures. Although a significant influence of the microstructure of the Si/Ge multilayers and SiGe layers was obtained on the
Journal of Applied Physics, 2000
Spectral Mueller matrices measured at multiple angles of incidence as well as Mueller matrix imag... more Spectral Mueller matrices measured at multiple angles of incidence as well as Mueller matrix images are recorded on the exoskeletons (cuticles) of the scarab beetles Cetonia aurata and Chrysina argenteola. Cetonia aurata is green whereas Chrysina argenteola is gold-colored. When illuminated with natural (unpolarized) light, both species reflect left-handed and near-circularly polarized light originating from helicoidal structures in their cuticles. These structures are referred to as circular Bragg reflectors. For both species the Mueller matrices are found to be nondiagonal depolarizers. The matrices are Cloude decomposed to a sum of non-depolarizing matrices and it is found that the cuticle optical response, in a first approximation can be described as a sum of Mueller matrices from an ideal mirror and an ideal circular polarizer with relative weights determined by the eigenvalues of the covariance matrices of the measured Mueller matrices. The spectral and image decompositions are consistent with each other. A regression-based decomposition of the spectral and image Mueller matrices is also presented whereby the basic optical components are assumed to be a mirror and a circular polarizer as suggested by the Cloude decomposition. The advantage with a regression decomposition compared to a Cloude decomposition is its better stability as the matrices in the decomposition are determined a priori. The origin of the depolarizing features are discussed but from present data it is not possible to conclude whether the two major components, the mirror and the circular polarizer are laterally separated in domains in the cuticle or if the depolarization originates from the intrinsic properties of the helicoidal structure.
Philosophical Magazine, 2012
Thin Solid Films, Nov 28, 2014
Thin Solid Films, Nov 28, 2014
Nano letters, Nov 26, 2014
Chirality, tailored by external morphology and internal composition, has been realized by control... more Chirality, tailored by external morphology and internal composition, has been realized by controlled curved-lattice epitaxial growth of InxAl1-xN nanospirals. The curved morphology of the spiral segments is a result of a lateral compositional gradient while maintaining a preferred crystallographic growth direction, implying a lateral gradient in optical properties. Individual nanospirals show an asymmetric core-shell structure with curved basal planes. Mueller matrix spectroscopic ellipsometry shows that the tailored chirality is manifested in the polarization state of light reflected off the nanospirals.
Optical Materials Express, Nov 5, 2014
Optical Materials Express, Jun 19, 2014
Materials Today: Proceedings, 2014
Thin Solid Films, Nov 28, 2014
Springer Series in Surface Sciences, 2014
ABSTRACT A brief description of the polarizing environment we are living in and the possibilities... more ABSTRACT A brief description of the polarizing environment we are living in and the possibilities for some animals to detect this polarization is made. This is followed by a presentation of how animals and plants generate polarized light, usually through reflection from micro- and nanostructures. Special attention is made to scarab beetles reflecting light with a high degree of circular polarization. Finally some comments on the biological aspects of polarization are made.
Thin Solid Films, Nov 28, 2014
Optics express, Jan 31, 2012
We studied the far-field optical response of supported gold-silica-gold nanosandwiches using spec... more We studied the far-field optical response of supported gold-silica-gold nanosandwiches using spectroscopic ellipsometry, reflectance and transmittance measurements. Although transmittance data clearly shows that the gold nanodisks in the sandwich structure interact very weakly, oblique reflectance spectra of s- and p-polarized light show clearly asymmetric line-shapes of the Fano type. However, all experimental results are very well described by modeling the gold nanodisks as oblate spheroids and by employing a 2 × 2 scattering matrix formulation of the Fresnel coefficients provided by an island film theory. In particular, the Fano asymmetry can be explained in terms of interference between the scattered waves from the decoupled nanodisks in the spectral range limited by their respective plasmon resonances. We also show that the reflectance and ellipsometry spectra can be described by a three-layer system with uniaxial effective dielectric functions.
Philosophical Magazine, 2012