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- Arwin, Hans, et al.
(författare)
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Sum decomposition of Mueller-matrix images and spectra of beetle cuticles
- 2015
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 23:3, s. 1951-1966
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Arwin, Hans
(författare)
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TIRE and SPR-enhanced SE for adsorption processes
- 2014
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Ingår i: Ellipsometry of Functional Organic Surface and Films. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642401275 - 9783642401282 ; , s. 249-264
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Bokkapitel (refereegranskat)abstract
- Ellipsometry configurations in internal reflection mode facilitate studies of adsorption processes without the light beam passing through the medium from which adsorption occurs. Monitoring of adsorption processes on surfaces in opaque media is thus possible. If the surface in addition has a thin semitransparent metal film in which surface plasmon polaritons can be excited, one can achieve very high sensitivity to small changes in surface mass density of an adsorbed biolayer. Thickness changes as small as one pm can be resolved. In this chapter the theory for Total Internal Reflection Ellipsometry (TIRE), also called surface plasmon resonance enhanced ellipsometry, will be described and instrumentation will be briefly discussed. TIRE applied in spectroscopic as well as in angle of incidence interrogation modes will be considered. Finally applications in the areas of bioadsorption processes, biosensing, gas adsorption and biolayer imaging will be reviewed.
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| 5. |
- Arwin, Hans, 1950-
(författare)
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TIRE and SPR-enhanced SE for adsorption processes
- 2018
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Ingår i: Ellipsometry of functional organic surfaces and films. - Cham : Springer. - 9783030093518 - 9783319758954 ; , s. 419-435
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Ellipsometry configurations in internal reflection mode facilitate studies of adsorption processes without the light beam passing through the medium from which adsorption accurs. Monitoring of adsorption processes on surfaces in opaque media is thus possible. If the surface in addition has a thin semitransparent metal film in which surface plasmon polaritons can be excited, one can achieve very high sensitivity to small changes in surface mass density of an adsorbed biolayer. Thickness changes as small as on pm can be resolved. In this chapter the theory for Total Internal Reflection Ellipsometry (TIRE), also called surface plasmon resonance enhanced ellipsometry, will be described and instrumentation will be briefly discussed. TIRE applied in spectroscopic as well as in angle of incidence interrogation modes will be considered. Finally applications in the areas of bioadsorption processes, biosensing, gas adsorption and biolayer imaging will be reviewed.
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| 7. |
- Arwin, Hans, 1950-, et al.
(författare)
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Total Internal Reflection Ellipsometry : monitoring of proteins on thin metal films
- 2006
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Ingår i: Proteins on surfaces. - Berlin, Heidelberg : Springer Verlag. - 9185457167 - 9783540326588 - 9783540326571 ; , s. 105-118
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- A measurement technique based on ellipsometry performed under conditions of total internal reflection is presented here. This technique is called total internal reflection ellipsometry (TIRE). When extended with the surface plasmon resonance effect, TIRE becomes a powerful tool for monitoring protein adsorption on thin metal films. A brief description of TIRE is presented here together with some examples of measurement system setups. Two examples of applications are included, followed by a short presentation of possible future applications of TIRE.
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| 8. |
- Arwin, Hans, 1950-, et al.
(författare)
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Total internal reflection ellipsometry : principles and applications
- 2004
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Ingår i: Applied Optics. - 0003-6935 .- 1539-4522. ; 43:15, s. 3028-3036
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Tidskriftsartikel (refereegranskat)abstract
- A concept for a measurement technique based on ellipsometry in conditions of total internal reflection is presented. When combined with surface plasmon resonance (SPR) effects, this technique becomes powerful for monitoring and analyzing adsorption and desorption on thin semitransparent metal films as well as for analyzing the semitransparent films themselves. We call this technique total internal reflection ellipsometry (TIRE). The theory of ellipsometry under total internal reflection combined with SPR is discussed for some simple cases. For more advanced cases and to prove the concept, simulations are performed with the Fresnel formalism. The use of TIRE is exemplified by applications in protein adsorption, corrosion monitoring, and adsorption from opaque liquids on metal surfaces. Simulations and experiments show greatly enhanced thin-film sensitivity compared with ordinary ellipsometry.
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