An Anisotropy of Gain in N2-Laser Pumped GaAs under Applied Electric Field

In the temperature range 80∼130 K, stimulated emission from N₂-laser pumped GaAs under an electric field has been observed and the anisotropy of the net gain for the polarity of the field has been found. The obtained maximum difference in the net gain in our experiments was 17 cm^-1 for applied field of 1.5 kV/cm at 130 K. The anisotropy of the net gain increased with temperature for the same field intensity and rapidly increased with increasing electric field over the threshold value of about 1 kV/cm. The origin of the anisotropy of the net gain has been qualitatively understood by the unidirectional laser action, caused by the drifting motion of carriers in a semiconductor.