Two-photon spectroscopy in InSb with cw CO₂ Lasers

Abstract

High resolution two-photon magneto-absorption spectra over a temperature range from 1.8– 100 K have been obtained for n-InSb using cw CO₂ lasers with $\overrightarrow e \bot \overrightarrow B$and $\overrightarrow e \parallel \overrightarrow B$polarizations in the Voigt geometry. A sensitive, derivative-photoconductive technique has allowed the observation of two-photon transitions not seen previously. Theoretical transition energies were calculated using an 8 × 8 Pidgeon-Brown model. Most of the observed transitions are adequately explained by the spherical selection rules Δs = 0, Δn = 0, ± 2. The variation of the energy gap with lattice temperature is found to compare favorably with the theoretical results of Camassel and Auvergne.