Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Detecting femtowatt with lasers
Laurent R. Gabet, Guy Michel Stéphan, Pascal Besnard
Abstract
We show that lasers can be used as detectors. The experimental set-up consists in optically injecting a slave laser with a laser whose linewidth is smaller. Heterodyne technique allows us to detect signals as small as -1 17 dBm or 0.2 photon per correlation time. We explain the experiment by interpreting the laser as a nonlinear amplifier and filter.