Single-sequence stable spectroscopicreflectometry using simultaneous measurementof incident light and reflected light: publisher’s note

2021 ◽  
Author(s):  
Heui Jae Pahk
Keyword(s):  
Incident Light ◽  
Reflected Light ◽  
Single Sequence

scholarly journals Electrical tuning of the polarization state of light using graphene-integrated anisotropic metasurfaces

2017 ◽  
Vol 375 (2090) ◽  
pp. 20160061 ◽  
Author(s):  
Shourya Dutta-Gupta ◽  
Nima Dabidian ◽  
Iskandar Kholmanov ◽  
Mikhail A. Belkin ◽  
Gennady Shvets
Keyword(s):  
Tilt Angle ◽  
Incident Light ◽  
Polarization State ◽  
Dynamic Control ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Dynamic Polarization ◽  
Reflected Light ◽  
Electro Optic ◽  
The Way

Plasmonic metasurfaces have been employed for moulding the flow of transmitted and reflected light, thereby enabling numerous applications that benefit from their ultra-thin sub-wavelength format. Their appeal is further enhanced by the incorporation of active electro-optic elements, paving the way for dynamic control of light's properties. In this paper, we realize a dynamic polarization state generator using a graphene-integrated anisotropic metasurface (GIAM) that converts the linear polarization of the incident light into an elliptical one. This is accomplished by using an anisotropic metasurface with two principal polarization axes, one of which possesses a Fano-type resonance. A gate-controlled single-layer graphene integrated with the metasurface was employed as an electro-optic element controlling the phase and intensity of light polarized along the resonant axis of the GIAM. When the incident light is polarized at an angle to the resonant axis of the metasurface, the ellipticity of the reflected light can be dynamically controlled by the application of a gate voltage. Thus accomplished dynamic polarization control is experimentally demonstrated and characterized by measuring the Stokes polarization parameters. Large changes of the ellipticity and the tilt angle of the polarization ellipse are observed. Our measurements show that the tilt angle can be changed from positive values through zero to negative values while keeping the ellipticity constant, potentially paving the way to rapid ellipsometry and other characterization techniques requiring fast polarization shifting. This article is part of the themed issue ‘New horizons for nanophotonics’.

Single-sequence stable spectroscopic reflectometryusing simultaneous measurement of incident light andreflected light

2021 ◽  
Author(s):  
Sin Yong Lee ◽  
Seung Woo Lee ◽  
GARAM CHOI ◽  
Yeongchan Cho ◽  
Heui Jae Pahk
Keyword(s):  
Simultaneous Measurement ◽  
Incident Light ◽  
Single Sequence

scholarly journals Neural control of tuneable skin iridescence in squid

2012 ◽  
Vol 279 (1745) ◽  
pp. 4243-4252 ◽  
Author(s):  
T. J. Wardill ◽  
P. T. Gonzalez-Bellido ◽  
R. J. Crook ◽  
R. T. Hanlon
Keyword(s):  
Neural Control ◽  
Incident Light ◽  
Dynamic Control ◽  
Activation Mechanism ◽  
Structural Coloration ◽  
Nanoscale Structures ◽  
Reflected Light ◽  
Skin Coloration ◽  
Reflectance Change ◽  
Fast Dynamic

Fast dynamic control of skin coloration is rare in the animal kingdom, whether it be pigmentary or structural. Iridescent structural coloration results when nanoscale structures disrupt incident light and selectively reflect specific colours. Unlike animals with fixed iridescent coloration (e.g. butterflies), squid iridophores (i.e. aggregations of iridescent cells in the skin) produce dynamically tuneable structural coloration , as exogenous application of acetylcholine (ACh) changes the colour and brightness output. Previous efforts to stimulate iridophores neurally or to identify the source of endogenous ACh were unsuccessful, leaving researchers to question the activation mechanism. We developed a novel neurophysiological preparation in the squid Doryteuthis pealeii and demonstrated that electrical stimulation of neurons in the skin shifts the spectral peak of the reflected light to shorter wavelengths (greater than 145 nm) and increases the peak reflectance (greater than 245%) of innervated iridophores. We show ACh is released within the iridophore layer and that extensive nerve branching is seen within the iridophore. The dynamic colour shift is significantly faster (17 s) than the peak reflectance increase (32 s), revealing two distinct mechanisms. Responses from a structurally altered preparation indicate that the reflectin protein condensation mechanism explains peak reflectance change, while an undiscovered mechanism causes the fast colour shift.

scholarly journals Обобщенная нуль-эллипсометрия в схеме "поляризатор-образец-анализатор"

2022 ◽  
Vol 130 (3) ◽  
pp. 377
Author(s):  
Н.В. СопинскиЙ ◽  
Г.П. Ольховик
Keyword(s):  
Incident Light ◽  
Photometric Method ◽  
Jones Matrix ◽  
Matrix Elements ◽  
Anisotropic System ◽  
Reflected Light ◽  
Sample Orientation ◽  
Anisotropic Systems ◽  
The One ◽  
Analytical Expressions

The null-method in generalized ellipsometry with the use of the compensator-free “polarizer ‒ sample ‒ analyzer” scheme is considered for the case of s- and p-polarized incident light on an anisotropic system. Analytical expressions are given that connect the measured angular value — the analyzer azimuth at the detected radiation intensity minimum — with the (2x2) anisotropic Jones matrix elements. To determine the optical and geometric parameters of the studied anisotropic systems, it is proposed to use this value’s dependence on the sample orientation (azimuth). The method sensitivity is estimated. It was found that it is comparable to the sensitivity of the “polarizer‒compensator‒sample‒analyzer” scheme. A comparative analysis of this method and the known photometric method of generalized ellipsometry in the “polarizer-sample-analyzer” scheme based on measuring the dependence of the reflected light intensity on the sample azimuth at the fixed polarizer and analyzer positions is carried out. It is estimated that, to obtain the same sensitivity of these two methods, the one arc minute error in the proposed method corresponds to the 0.05% relative error in determining the energy reflection coefficient in the photometric method.

Nondestructive Measurement of the Subsurface Structure of Biological Material Having Cellular Structure by Using Near-Infrared Spectroscopy

1996 ◽  
Vol 50 (9) ◽  
pp. 1117-1124 ◽  
Author(s):  
Satoru Tsuchikawa ◽  
Kazuo Hayashi ◽  
Shigeaki Tsutsumi
Keyword(s):  
Surface Roughness ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Cellular Structure ◽  
Near Infrared ◽  
Incident Light ◽  
Physical Conditions ◽  
Light Passing ◽  
Nir Light ◽  
Reflected Light

Biological materials–wood is a typical example–are widely used in a state where not only the cellular structure but also its bulky shape is retained. NIRS (near-infrared spectroscopy) may be called for as a promising technique to analyze the physical state of such materials as well as the chemical composition. In this report, the effects of physical conditions found in wood on the absorption of NIR radiation are examined. In the experiments, conifers (Sitka spruce) that had various degrees of surface roughness and different orientations of fibers to the direction of incident light were used. Results of these measurements showed that the orientation of fibers and the surface roughness of wood were directly related to the absorbance. In addition, it became clear that the behavior of diffusely reflected light in wood could be expressed by Kubelka–Munk theory and fell into three categories according to the characteristic of the absorption and scattering coefficient. On the basis of these results, a new concept for the behavior of NIR light passing through material made of hollow fibers has been proposed.

A survey of reflectivity in silvery teleosts

1966 ◽  
Vol 46 (3) ◽  
pp. 685-722 ◽  
Author(s):  
E. J. Denton ◽  
J. A. C. Nicol
Keyword(s):  
Coastal Waters ◽  
Incident Light ◽  
Sea Lamprey ◽  
Projected Area ◽  
Background Light ◽  
Pelagic Fishes ◽  
Reflected Light ◽  
Salmon Parr

A survey has been made of reflecting layers in the integument of selected fishes, including silvery sea lamprey and various silvery and partially translucent teleosts. Lamprey and juvenile rockling have only a stratum argenteum. Other silvery teleosts have a layer of oriented reflecting platelets lying outside the stratum argenteum; these lie more or less parallel to the vertical to the surface of the water.In dace, herring, and salmon parr the platelets on the upper flanks are tipped slightly upwards; but in some pelagic fishes, e.g. the mackerel and gar-fish, the platelets here are tipped downwards. Smelt, sand smelt, half-beaks, found in shallow or coastal waters, are partially translucent, partially silvery. The implications of these arrangements of reflecting layers are discussed. Both in clear oceanic waters, away from the surface, and in shallow or turbid rivers or ponds, light is distributed almost symmetrically about the vertical to the surface, and the greatest intensity is directed downwards. Under these conditions the reflecting layers diminish thevisibility of the fish from most fields of view because they reflect light approximately equal to the background light against which the fish is seen. On the lower flanks, when the surface is sloping, the reflected light tends to be spread and to beless intense than the incident light. Thin fishes, dark above with vertically reflecting sides, are effectively camouflaged except for the ventral extremity. The lower flanks of tapering or rounded fishes are well camouflaged by reflexion from below and behind because the platelets slope inwards towards the tail, and the projected area of incidence relative to reflexion is thereby increased.

scholarly journals Inverse ray mapping in phase space for two-dimensional reflective optical systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carmela Filosa ◽  
Jan ten Thije Boonkkamp ◽  
Wilbert IJzerman
Keyword(s):  
Phase Space ◽  
Incident Light ◽  
Mapping Method ◽  
New Method ◽  
Optical Systems ◽  
Space Representation ◽  
Two Dimensional ◽  
Reflected Light ◽  
Straight Lines ◽  
Phase Space Representation

AbstractA new method to compute the target photometric variables of non-imaging optical systems is presented. The method is based on the phase space representation of each surface that forms the optical system. All surfaces can be modeled as detectors of the incident light and emitters of the reflected light. Moreover, we assume that the source can only emit light and the target can only receive light. Therefore, one phase space is taken into account for the source and one for the target. For the other surfaces both the source and target phase spaces are considered. The output intensity is computed from the rays that leave the source and hit the target. We implement the method for two-dimensional optical systems, and we compare the new method with Monte Carlo (MC) ray tracing. This paper is a proof of principle. Therefore, we present the results for systems formed by straight lines which are all located in the same medium. Numerical results show that the intensity found with the ray mapping method equals the exact intensity. Accuracy and speed advantages of several orders are observed with the new method.

scholarly journals A Simple Simulation of Surface Plasmon Resonance in The Kretschmann Configuration Using Google Sheets

2020 ◽  
Vol 16 (2) ◽  
pp. 83-91
Author(s):  
N. K. Quang ◽  
N. P. Q. Anh ◽  
H. C. Hieu
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Incident Light ◽  
Layer System ◽  
Incident Wavelength ◽  
Web Based ◽  
Kretschmann Configuration ◽  
Reflected Light ◽  
Simple Simulation

This article describes a simple numerical simulation of three-layer surface plasmon resonance (SPR) in the Kretschmann configuration. The calculation was performed in Google Sheets, a web-based spreadsheet environment that functions similarly to Microsoft Excel where it is easily accessible for students via the internet. Specifically, Fresnel’s equations were utilized to calculate the intensity of the reflected light for the p-polarized incident light on a three-layer system. The complex functions were utilized to plot the SPR curves. We examined the change of the resonance angle by the influence of the incident wavelength. The simulation was also performed for different thicknesses of the gold film layer. To demonstrate the sensitivity, we obtained the SPR curves with the variation of the refractive index in the sensitive medium. The SPR accuracy was analysed by comparing our obtained result with the published work. It is intended to incorporate into undergraduate instrumental analysis courses.

FAST RENDERING WATER SURFACE FOR OUTDOOR SCENES

2001 ◽  
Vol 01 (02) ◽  
pp. 313-327 ◽  
Author(s):  
KATSUMI TADAMURA ◽  
XUEYING QIN ◽  
GUOFANG JIAO ◽  
EIHACHIRO NAKAMAE
Keyword(s):  
Environmental Assessment ◽  
Water Surface ◽  
Scattered Light ◽  
Incident Light ◽  
Light Sources ◽  
Direct Sunlight ◽  
Reflected Light ◽  
Outdoor Scenes ◽  
Tracing Techniques ◽  
Fast Rendering

Water surface is an important element for rendering a realistic landscape image, particularly for visual environmental assessment. The incident light from the water surface to the viewpoint generally consists of two components, reflected and refracted light. The source of the latter is further subdivided into reflected light from the bottom of the water and scattered light in it. In order to render a realistic water surface, the calculation for each component of the light is a quite complex and time consuming task. We propose the fast rendering algorithms of the water surface for visual environmental assessment of outdoor scenes. The features are: (1) the reflected light from the water surface is rendered very quickly through the quasi-ray tracing techniques, which employ inversion and reflection mapping with consideration of the depth of objects mirrored on the water surface; (2) the refracted light coming through the water surface, which gives the color of water, is efficiently calculated by using a look-up table in which both characteristics of the light sources (both direct sunlight and skylight) and the effects of scattering and attenuation depending on turbidity are taken into account. In order to testify the proposed algorithms, some examples are given.

Quantitative colours of opaque minerals

1989 ◽  
Vol 53 (369) ◽  
pp. 71-78 ◽  
Author(s):  
A. Peckett
Keyword(s):  
Incident Light ◽  
Polarized Light ◽  
Dielectric Tensor ◽  
Diagnostic Aid ◽  
Reflected Light ◽  
Principal Axes ◽  
Opaque Minerals ◽  
Low Symmetry ◽  
Mineral Identification ◽  
Microscope Stage

AbstractAnisotropic opaque minerals viewed in reflected light microscopy show two sets of colours: the colours seen in plane polarized light which change as the section is rotated on the microscope stage, and the colours seen between crossed polars which change as the analyser is uncrossed. These latter colours are known variously as polarization colours or anisotropic rotation tints, but are here referred to as anisotropy colours. They are commonly a diagnostic aid to correct mineral identification. All these colours occur as a consequence of the dispersion of the relative permittivity (dielectric) tensor—the variation in the values of the tensor with wavelength of incident light and in low symmetry crystals, the variation in the directions of the principal axes of the tensor with wavelength.In this paper, it is shown that the colour seen in plane polarized light and the anisotropy colours can be predicted for any orientation of section, at any stage angle, and for any degree of uncrossing of the analyser by calculations based on the dielectric tensor values, and these predicted colours compare favourably with the observed values. Three minerals are studied in this paper as examples: stannite, covelline, and bournonite.

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