Overcoming inefficient detection in sub-shot-noise absorption measurement and imaging.

Photon-number squeezing and correlations enable measurement of absorption with an accuracy exceeding that of the shot-noise limit. However, sub-shot noise imaging and sensing based on these methods require high detection efficiency, which can he a serious obstacle it measurements are carried out in "difficult" spectral ranges. We show that this problem can he overcome through the phase-sensitive amplification before detection. Here we propose an experimental scheme of sub-shot-noise imaging with tolerance to detection losses. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement