Frequency dependence of two-photon absorption in InSb andHg1−xCdxTe

The frequency dependence of two-photon absorption is measured over a wide range in InSb and ${\mathrm{Hg}}_{0.78}$ ${\mathrm{Cd}}_{0.22}$Te, showing good agreement with a nonparabolic-band perturbation calculation and wide divergence from "tunneling" theory. Associated photoconductivity measurements, required in the analysis, confirm that Auger scattering is the dominant process at room temperature in $n$-InSb, but at low temperatures have yielded a direct value of the lifetime of $\tau \left(77\mathrm{} \mathrm{K}\right)=143\mathrm{}$ ns for radiative recombination.