Saturation of optical absorption by a nonequilibrium electron-hole plasma in InSb crystals

Abstract

A high degree of saturation of optical absorption in InSb is observed at 2 \ifmmode^\circ\else\textdegree\fi{}K by using several lines (between 5.5 and 5 \ensuremath{\mu}m) of a cw CO laser. Luminescence is studied in the same conditions. A model of dynamic Burstein shift is presented which allows us to fit both theoretical transmission and luminescence with the data by taking into account band-gap renormalization and carrier heating. We emphasize that the principal experimental uncertainties arise from inhomogeneous pumping and interference effects in the sample. We show that a weak transverse magnetic field reduces the transmission of circularly polarized light.