Aims. The SiC optical constants are fundamental inputs for radiative transfer (RT) models of astrophysical dust environments. However, previously published values contain errors and do not adequately represent the bulk physical properties of the cubic (β) SiC polytype usually found around carbon stars. We provide new, uncompromised optical constants for βand α-SiC derived from single-crystal re...

The linear optical response of hexacene single crystals over a spectral range of 1.3-1.9 eV was studied using polarization-resolved reflectance spectroscopy at cryogenic temperatures. We observe strong polarization anisotropy for all optical transitions. Pronounced deviations from the single-molecule, solution-phase spectra are present, with a measured Davydov splitting of 180 meV, indicating s...

We study mechanically exfoliated nanosheets of franckeite by quantitative optical microscopy. The analysis of transmission-mode and epi-illumination-mode optical microscopy images provides a rapid method to estimate the thickness of the exfoliated flakes at first glance. A quantitative analysis of the optical contrast spectra by means of micro-reflectance allows one to determine the refractive ...

Epicuticular waxes influence leaf reflectance, but the spatiotemporal dynamics in their reflectance properties have not been properly characterized, and its consequences remain unknown. In this study, we analysed the seasonal changes in wax reflectance of Scots pine needles. It tended to decrease with needle age and towards lower positions within the canopy. In addition, we also identified a cl...

We demonstrate tunable mirrors that consist of a porous silicon microcavity infiltrated with liquid crystal molecules. We show theoretically that by utilizing the electro-optic properties of liquid crystals and the sensitivity of the microcavity resonance position to small changes in optical thickness, the porous silicon active mirror can be switched on (high reflectance) and off (low reflectan...

In this paper, we propose an approach for the recovery of the dichromatic model from two hyperspectral or multispectral images, i.e., the joint estimation of illuminant, reflectance, and shading of each pixel, as well as the optical flow between the two views. The approach is based on the minimization of an energy functional linking the dichromatic model to the image appearances and the flow be...

We demonstrate a reverse design method for realizing a broad range of optical filters based on integrated optical waveguides and experimentally verify example designs on a CMOS-compatible silicon-on-insulator (SOI) platform. The reflectance-based filters allow for control of both phase and amplitude of the optical response. Among this device's many potential applications we highlight and numeri...

We describe the protocol for an inexpensive and nondestructive optical reflectance assay for the measurement of biofilm formation. Reflectance data are obtained using an Ocean Optics (Dunedin, Florida) USB 2000 spectrometer with a polychromatic light source. A fiber optic cable is used both for illumination and collection, and Ocean Optics OOIBase32 Platinum software is used for preliminary pro...

PURPOSE To determine whether reflectance changes of the retina after electrical suprachoroidal-transretinal stimulation (STS) can be detected with a newly developed optical imaging fundus camera. METHODS Ten eyes of 10 cats were studied. A small retinal area was focally stimulated with electric currents passing between an active electrode placed in the fenestrated sclera and a reference elect...

The reported optical constants of uranium differ from that of vacuum significantly more than other elements do over the range of about 150 to 350 eV. This suggests that uranium could be used to produce high reflectance imaging mirrors for many soft x-ray applications. Elemental uranium is too chemically active to be used as a front surface mirror without protection. We computed the expected ref...