the National Natural Science Foundation of China(No.12020101003);the State Key Laboratory of Low-Dimensional Quantum Physics for the strong support;Tsinghua University for the start-up grant;the support from the Singapore Ministry of Education via the AcRF Tier 3 Programme“Geometrical Quantum Materials”(No.MOE2018-T3-1-002);AcRF Tier 2(Nos.MOE2018-T2-2-068 and MOE2019-T2-1-004).
Optical parametric oscillators(OPOs)have been widely applied in spectroscopy,squeezed light,and correlated photons,as well as quantum information.Conventional OPOs usually suffer from a high power threshold limited by...