Artificial birefringence introduced by porosity in GaP

Abstract

Porosity-induced birefringence in a GaP membrane is studied using a method based on the analysis of beats in unpolarized and polarized transmittance spectra as well as in angular dependence of optical spectra. Birefringence as high as n e − n o = 0.25 was measured in a porous GaP membrane with the degree of porosity close to 40%. The measured values of n e and n o are compared with those calculated in the frame of effective medium theory for a GaP membrane with appropriate morphology.

Surface Second-Harmonic Generation from Vertical GaP Nanopillars

“…31,32 Because of the symmetry of the χ (2) tensor we cannot see any SHG from bulk (100) GaP, with the incident light being normal to the (100) surface. Therefore the observed SHG originates from the NPs and the substrate contribution can be neglected.…”

“…GaP as a bulk lacks birefringence and in order to enhance the efficiency of SHG, phase matching condition can be obtained by induced birefringence, e.g., as in porous GaP. , Because of the symmetry of the χ (2) tensor we cannot see any SHG from bulk (100) GaP, with the incident light being normal to the (100) surface. Therefore the observed SHG originates from the NPs and the substrate contribution can be neglected.…”

Characterization of porous polar semiconductors by their optical spectra in the region of phonon and plasmon-phonon excitations

“…It covers a rather wide range of compounds, beginning from porous silicon and oxides thereof, including alumi num oxide and some other semiconductors. As for the A 3 B 5 semiconductors, direct experiments were per formed only for gallium phosphide [13,14]. In this work, we restrict ourselves to the consideration of a uniaxial material.…”

“…The birefringence is rather large, on the order of 0.2-0.3, and its maximum corresponds to the porosity of 50-60%. According to experimental data [14], the porous layer of GaP (111) can be considered as a uniaxial positive anisotropic material with Δn = 0.25. Our calculations with use of the parameters that are presented in [14] coincided with this value almost completely.…”

Form‐anisotropy of 2D nanostructures: Modeling approaches comparison

“…During the last few years birefringence caused by form‐anisotropy of 2D nanostructures has been studied intensively both experimentally and theoretically for different systems in a wide spectral range. Artificial birefringence has been reported for porous silicon 1, porous alumina 2, 3, oxidized porous silicon 4, and porous GaP 5 in the visible and near infrared spectral regions. Also an artificial birefringence of stacked hollow acrylic pipes in a triangular array 6 in the microwave region has been demonstrated.…”