Noiseless single-photon isolator at room temperature

Abstract Nonreciprocal devices, such as isolators, are of great importance for optical communication and information processing. To bypass the limitation a strong magnetic field imposed by traditional Faraday magneto-optic effect, many alternative mechanisms have been proposed to demonstrate magnetic-free nonreciprocity. However, limited drive-induced noise, noiseless isolator capable working in quantum regime has yet be realized experiment. Here, we show all-optical with genuine single photons hot atoms. We experimentally study this mechanism using an open V-type level scheme low insertion loss 0.6 dB high isolation 30.3 bandwidth up hundreds megahertz. Furthermore, nonreciprocal direction can truly reversed only tuning frequency pump laser same setup. Our relies on widely used technology is thus universal robust.