Coherent Coupling between Microwave and Optical Fields via Cold Atoms**Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0301800 and 2016YFA0302800, the National Natural Science Foundation of China under Grant Nos 11822403, 91636218, U1801661, 11704131 and 61875060, the Natural Science Foundation of Guangdong Province under Grant Nos 2016A030310462 and 2015TQ01X715, the KPST of Guangzhou under

Abstract

We demonstrate a long-coherent-time coupling between microwave and optical fields through cold atomic ensembles. The phase information of the microwave field is stored in a coherent superposition state of a cold atomic ensemble and is then read out by two optical fields after 12 ms. A similar operation of mapping the phase of optical fields into a cold atomic ensemble and then retrieving by microwave is also demonstrated. These studies demonstrate that long-coherent-time cold atomic ensembles could resonantly couple with microwave and optical fields simultaneously, which paves the way for realizing high-efficiency, high-bandwidth, and noiseless atomic quantum converters.