An all-optical noise eater

Summary form only given. We use nonlinear absorption to reduce the shot-to-shot energy fluctuations of a laser. The sample has to have small or no linear absorption and the nonlinear losses should be small as well. Also, the response time of the nonlinearity should not exceed the laser pulsewidth, and the recovery time of the sample has to be smaller than the time between consecutive pulses. In order to satisfy these requirements we use two-photon absorption (2PA) as the optical limiting mechanism. 2PA has been proven useful for amplitude squeezing; what we present here, however, is a drastic technical noise reduction. We have demonstrated significant reduction in the noise figure by allowing reduced throughput of the device.