We report an experimental investigation of an ultrasensitive coherent amplifier (USCA) operated at a 10-Hz repetition rate. We measure its quantum-noise-limited sensitivity, amplification, and image resolution. The USCA consisted of two Nd:YAG amplifiers in series with a high-gain four-wave Brillouin mirror with SnCl4 as the Brillouin medium. We measure a noise-equivalent-energy sensitivity of 1.96 × 10-19 J/mode or 1 photon/mode at a quantum efficiency of 96%. The system has an overall optical gain of 2.5 × 1013. With a version of the USCA equipped with an imaging lens system, we demonstrate the amplification and phase conjugation of entire images with a resolution of 164 µrad across a field of view of 4 mrad or 21 × 21 resolution elements. To our knowledge, this is the first demonstration of a repetitively pulsed USCA.
© 1992 Optical Society of America
Rolf W. F. Gross, Lissa Garman-Du Vall, and Sherwin T. Amimoto, "Single-photon detection and imaging with a 10-Hz repetitively pulsed ultrasensitive coherent amplifier," Opt. Lett. 17, 82-84 (1992)