Abstract

In laser spectroscopy, sensitivity limitations mainly arise from laser amplitude noise. One way of improving the detection sensitivity consists of encoding the useful optical information at frequencies above laser noise bandwidth to reach the shot noise limit (fundamental quantum noise). This may be achieved via nearly degenerate four-wavemixing (FWM) processes to transfer a high-frequency (HF) amplitude¹ (or frequency²) modulation of an incident saturating beam to a counterpropagating unmodulated probe beam, whose amplitude is monitored.

© 1987 Optical Society of America