A new two-wave-mixing interaction with gain through a Bi12SiO20 liquid-crystal light valve is presented. We show that the diffraction of a pump beam in the direction of a weak signal leads to a net amplification of the signal beam, with no need for a phase shift between the interference pattern and the induced index grating. A two-wave-mixing gain of 10 and a 150-ms response time are obtained with a 8.8-µm -thick liquid-crystal layer, a total intensity of the interacting beams of only 200 μW/cm2, and an ac external voltage of ±6 V . Image amplification is also demonstrated.
© 1997 Optical Society of America
A. Brignon, I. Bongrand, B. Loiseaux, and J.-P. Huignard, "Signal-beam amplification by two-wave mixing in a liquid-crystal light valve," Opt. Lett. 22, 1855-1857 (1997)