Exponential growth of periodic surface ripples generated in laser-induced etching of GaAs

The exponential growth of periodic surface ripples in laser-induced etching of GaAs was demonstrated for the first time. The etched depth of the ripple structure increased exponentially with increasing laser irradiation time because of the nonlinear effect of stimulated surface-plasma-wave scattering, while the etched depth of holographic grating increased linearly. A small-signal gain of 5.6%/min was obtained in the growth of the etched depth which was consistent with the theoretical value.