Abstract

We have recently shown that by operating near the band-edge in photorefractive semiconductors, very large beam coupling gain coefficients (Γ = 16.3 cm⁻¹) can be achieved at wavelength regions with moderate absorption coefficients (α < 3 cm⁻¹).¹ The largest net gain we have observed (Γ_−α = 13.3 cm⁻¹) resulted in more than a factor of 200 amplification of a weak signal beam in our 4-mm long crystal.

© 1990 Optical Society of America