Abstract

Electronic nonlinear absorption has been observed in thin films of InGaAsP grown by liquid phase epitaxy (LPE). The nonlinear optical absorption studies utilize a thin film of InGaAsP grown by LPE, lattice matched to InP, with a band gap corresponding to 1.06 μm. Gold is vacuum deposited on this grown layer, and a Nd:YAG laser (wavelength = 1.06 μm) is then used to probe the quaternary layer using the substrate as a window. The incident beam passes through the substrate and grown layer and is then reflected by the gold layer back through the sample again. We have noted nonlinearities (in output intensity as a function of input intensity) due to electronic absorption (separated from thermal effects) with short (1-μs) laser pulses and thermal effects (time scale, 20 μs) with longer (60-μs) laser pulses.

© 1987 Optical Society of America