Monolithic measurement of optical gain and absorption in PbTe

An integrated technique for measuring optical gain and absorption is described. The gain and absorption coefficients are measured as a function of wavelength in PbTe near the direct band gap (∼5.75 μm at 77 °K). It is possible to measure optical gains of up to 100 cm−1 and absorption coefficients up to 300 cm−1. The usefulness to a theoretical analysis of the well−correlated gain and absorption data obtained by this method is discussed with a comparison of experimental data with a simple parabolic band theory.