%A Ming-Bo Chen(陈明博), Bao-Chuan Wang(王保传), Si-Si Gu(顾思思), Ting Lin(林霆), Hai-Ou Li(李海欧), Gang Cao(曹刚), and Guo-Ping Guo(郭国平) %T Micro-scale photon source in a hybrid cQED system %0 Journal Article %D 2021 %J Chin. Phys. B %R 10.1088/1674-1056/abe29b %P 48507- %V 30 %N 4 %U {https://cpb.iphy.ac.cn/CN/abstract/article_123446.shtml} %8 2021-03-16 %X Coherent photon source is an important element that has been widely used in spectroscopy, imaging, detection, and teleportation in quantum optics. However, it is still a challenge to realize micro-scale coherent emitters in semiconductor systems. We report the observation of gain in a cavity-coupled GaAs double quantum dot system with a voltage bias across the device. By characterizing and analyzing the cavity responses to different quantum dot behaviors, we distinguish the microwave photon emission from the signal gain. This study provides a possibility to realize micro-scale amplifiers or coherent microwave photon sources in circuit quantum electrodynamics (cQED) hybrid systems.