Search results for "Refractive index"
showing 10 items of 332 documents
Nano-holes vs nano-cracks in thin gold films: What causes anomalous THz transmission?
2015
Nano-structuring materials can change their properties extraordinarily, but so can defects caused by manufacturing. We study the effect of capacitive defects on terahertz transmission in golden nanomeshes, and find their influence crucial.
Solvation parameters of solutes: an attempt of improvements in characterization and determination
2008
We are presenting here an updated version of our predictive model of solvation parameters of solutes, based on a simplified molecular topology (J. Chem. Inf. Model, 2006, 46, 1723-1734). The learning experimental database of this model is presently larger than in our first version and includes more compounds with more than one functional group of the same type. This experimental database is also surer, in the sense that it only includes compounds in liquid state at room temperature, when the polarizability of a compound in solution is established via its refractive index in gas or crys- talline state. Indeed, we demonstrate in this paper, a bias in this case.
High speed optical transmission at 2 μm in subwavelength waveguides made of various materials
2018
We report the transmission of a 10 Gbps telecommunication signal at 2 μm in waveguides made of three different materials: Si, SiGe and TiO2. Bit error rates below 10−9 can be achieved after transmission in the devices with subwavelength dimensions.
Whispering gallery mode resonators covered by a ZnO nanolayer
2020
Abstract The exceptional ability of whispering gallery mode resonators (WGMRs) to confine light within makes them interesting for sensing applications. The small size and high values of quality (Q) factors of the WGMR can be combined with a broad range of supporting optical elements. The surface of the resonator can be coated to enhance the desired attributes. In this paper, the impact of the ZnO layer thickness on the Q-factor of the WGMR has been studied. WGMRs were fabricated on a tip of a standard telecom fiber melted with an oxyhydrogen flame. The surface of the WGMR was coated with ZnO nanolayers of different thickness (5–100 nm) by atomic layer deposition (ALD). The Q-factor of as-pr…
Second-harmonic generation in Langmuir–Blodgett monolayers of stilbazium salt and phenylhydrazone dyes
1988
The second-order nonlinear optical susceptibilities χ(2) of several phenylhydrazone and stilbazium salt dyes in Langmuir–Blodgett monolayers have been determined from second-harmonic-generation measurements. Three of the substances demonstrated χ(2) values greater than 10−6 electrostatic units, although two of the three did not absorb light significantly at the second-harmonic wavelength.
<title>Holographic recording in amorphous chalcogenide semiconductor thin films</title>
2000
ABSTRACT The photoinduced changes ofoptical properties and holographic recording in amorphous chalcogenide semiconductor As-S- Se and As2S3 thin films have been studied. The possibilities of the practical applications of these materials as the photoresists for the production of the relief holograms and holographic optical elements are discussed. It is shown that theself-enhancement phenomenon of holographic recording in amorphous chalcogenide semiconductor films by light orthermal treatment can be used to increase the diffraction efficiency ofthe holograms.Keywords: chalcogenide semiconductors, amorphous films, photoresists, photoinduced processes, relaxation processes,self-enhancement of h…
Fourth order cascaded Raman shift in As38Se62 chalcogenide suspended core fiber pumped at 1.995 μm
2011
Fourth order cascaded Raman wavelength shift is demonstrated in As 38 Se 62 suspended core fiber using 1995 nm nanosecond source. The measured Raman gain coefficient is∼2×10−11 m/W at 1995 nm. The Raman peaks are reproduced by numerical simulations.
Self-Trapped Localized Modes in Photonic Crystal Fibers
2002
We demonstrate the existence of self-trapped localized modes in photonic crystal fibers. We analyze these solutions in terms of the parameters of the photonic crystal cladding and the nonlinear coupling.
Light-induced ionic processes in optical oxide glasses
1991
Abstract The density of optical glasses is changed by the influence of light capable of generating color centers in these materials. Such defect generation is not only an electronic process, but an atomic displacement is also necessary. The strong localization of electronic and vibrational excitations in the glass network leads to the high efficiency of sub-threshold defect generation. Secondary ionic processes lead to the changes of basic glass properties (light refractive index, density, mechanical strength, etc.); thus, it is possible to use optical glasses as light detectors for appropriate wavelengths.
Enhanced Nonlinear Optical Coefficients of MAPbI3 Thin Films by Bismuth Doping
2020
The poor photostability under ambient conditions of hybrid halide perovskites has hindered their recently explored promising nonlinear optical properties. Here, we show how Bi3+ can partially substitute Pb2+ homogeneously in the commonly studied MAPbI3, improving both environmental stability and photostability under high laser irradiation. Bi content around 2 atom % produces thin films where the nonlinear refractive (n2) and absorptive coefficients (β), which modify the refractive index (Δn) of the material with light fluence (I), increase up to factors of 4 and 3.5, respectively, compared to undoped MAPbI3. Higher doping inhibits the nonlinear parameters; however, the samples show higher f…