Abstract
In a previous paper measurements were reported of two-photon absorption (TPA) in the narrow gap semiconductors InAs and InSb utilising the mid-infrared tunability of CLIO. An assumption had to be made concerning the lifetime of the excited carriers in order to interpret the results. We have now made a direct measurement of the lifetime of two-photon-induced free holes in InAs and InSb using an excite-probe technique. We have measured the TPA coefficient over the entire range from one-photon to two-photon threshold, showing good agreement with a non-parabolic band model for the process.