Coherent light-matter interaction at the single photon level is a long-standing goal for quantum operations. To reach such strong coupling regime, previous studies mainly focus on improving the quality (Q) factor and reducing the mode volume (V) of the same optical resonators, but they have already reached their limits due to current fabrication and other technological restrictions. Very recently, a team led by Professor Yun-Feng Xiao and Professor Qihuang Gong at Peking University, collaborated with Columbia University, have demonstrated the strong coupling via dark state resonances in a coupled-cavity quantum electrodynamics system, by removing the strict requirement of figure-of-merit (Q/V) for the same cavity. Strong coupling has been demonstrated in a highly dissipative cavity even with the decay rate in excess of the interaction strength by two orders of magnitude. This provides a promising platform for overcoming decoherence in quantum operations and advancing the coherent manipulation of polariton qubits.

Reference: Yong-Chun Liu, Xingsheng Luan, Hao-Kun Li, Qihuang Gong, Chee Wei Wong, and Yun-Feng Xiao, “Coherent polariton dynamics in coupled highly-dissipative cavity quantum electrodynamics,” 112, 213602 (2014).