Margaret H. Weiler

Nonparabolicity and exciton effects in two-photon absorption in zincblende semiconductors

Abstract The two-photon absorption coefficient is calculated from perturbation theory for direct-gap zincblende semiconductors using exact nonparabolic energies and matrix elements. The enhancement due to exciton effects is included. The results are compared to experiment and to other theories including the tunneling or Keldysh theory.

Landau levels in the valence band of tellurium

Abstract The Landau levels in p -type tellurium were calculated, treating exactly the interaction between the two upper valence bands at the corner of the Brillouin zone. Cyclotron resonance transition energies and matrix elements were computed, in excellent agreement with experimental results at 337 μ and 195 μ, using new values for the parameters of the k ∼ . p ∼ model.

Magnetoabsorption in n-type InSb from 8 to 15 μm

Abstract Magnetoabsorption measurements in n-type InSb at T≅30K have been made between ∼ 8 and 15 μm using magnetic fields up to 150 kOe. The observed absorption peaks are identified as due to combined resonance, harmonics of cyclotron resonance and the corresponding LO phonon-assisted resonances. These resonant absorptions are considered to be important in the interpretation of the observed magnetic field behavior of the threshold and output power of the InSb spin-flip Raman laser pumped with 10.6 μm CO2 laser.

Conduction and valence band effective mass parameters in InSb

Abstract New parameters are obtained for the quasi-Ge model for the conduction and valence bands of InSb. The calculated transition energies fit the results of our interband magnetoreflection experiments and earlier intraband experiments.

Selection rules for one- and two-photon magneto-absorption in zincblende semiconductors

Abstract Selection rules are obtained for one- and two-photon optical transitions, in zincblende semiconductors, for an applied magnetic field parallel to the three crystal axes [001], [110], and [111], for optical polarizations σ L , o R , o, and π. Selection rules are found for transitions induced by k H ≠ 0 effects, warping, inversion asymmetry, and combinations of these perturbations. Impurity-assisted transitions are also considered. These results have recently been confirmed by studies of the angular dependence of electric- dipole-induced spin resonance in HgSe.

Hole-phonon interaction in tellurium

Abstract The effective mass of p-Te increases as the cyclotron frequency approaches the longitudinal optical phonon frequency of 116 cm −1 . This increase is caused by hole-phonon interaction and valence band nonparabolicity.

Two-photon spectroscopy in InSb with cw CO2 Lasers

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.

New Theoretical Results for the InSb Spin-Flip Raman Laser

The Stokes output intensity is calculated, taking into account the spatial dependence of the pump and Stokes intensities and cavity boundary conditions. Both analytical and numerical results are obtained for the two allowed pump polarizations, and are compared with experiment. The effect of anti-Stokes generation is discussed.