Abstract

We recently reported observations of the photorefractive effect in GaAs using beam coupling with 40-picosecond pulses.¹ In these observations, several effects interact to modify the transmission of a weak probe pulse in the presence of a strong pump pulse from that experienced by the weak probe pulse alone. The photorefractive effect transfers energy from one beam to the other in a direction controlled by the crystallographic axes.² Transient energy transfer due to the free-carrier grating transfers energy from the strong pump to the weak probe.³ Two-photon absorption due to the presence of the strong pump causes enhanced probe loss. In addition, effects of lesser importance such as saturation of the donor and acceptor absorption at the EL2 and EL2+ levels, absorption gratings, and free-carrier absorption modify the probe transmission in the presence of the pump.

© 1987 Optical Society of America