Simultaneous Kerr comb formation and second-harmonic generation with on-chip microresonators can greatly facilitate comb self-referencing for optical clocks and frequency metrology.Moreover,the presence of both second...Simultaneous Kerr comb formation and second-harmonic generation with on-chip microresonators can greatly facilitate comb self-referencing for optical clocks and frequency metrology.Moreover,the presence of both second-and third-order nonlinearities results in complex cavity dynamics that is of high scientific interest but is still far from being well-understood.Here,we demonstrate that the interaction between the fundamental and the second-harmonic waves can provide an entirely new way of phase matching for four-wave mixing in optical microresonators,enabling the generation of optical frequency combs in the normal dispersion regime under conditions where comb creation is ordinarily prohibited.We derive new coupled time-domain mean-field equations and obtain simulation results showing good qualitative agreement with our experimental observations.Our findings provide a novel way of overcoming the dispersion limit for simultaneous Kerr comb formation and second-harmonic generation,which might prove to be especially important in the near-visible to visible range where several atomic transitions commonly used for the stabilization of optical clocks are located and where the large normal material dispersion is likely to dominate.展开更多
基金supported in part by the National Science Foundation under grant ECCS-1509578the Air Force Office of Scientific Research under grant FA9550-15-1-0211+3 种基金the DARPA PULSE program through grant W31P40-13-1-0018 from AMRDECfunding from the National Natural Science Foundation of China under grant 6169190011/12,61420106003the Beijing Natural Science Foundation under grant 4172029funding from the Marsden Fund and the Rutherford Discovery Fellowships of the Royal Society of New Zealand.
文摘Simultaneous Kerr comb formation and second-harmonic generation with on-chip microresonators can greatly facilitate comb self-referencing for optical clocks and frequency metrology.Moreover,the presence of both second-and third-order nonlinearities results in complex cavity dynamics that is of high scientific interest but is still far from being well-understood.Here,we demonstrate that the interaction between the fundamental and the second-harmonic waves can provide an entirely new way of phase matching for four-wave mixing in optical microresonators,enabling the generation of optical frequency combs in the normal dispersion regime under conditions where comb creation is ordinarily prohibited.We derive new coupled time-domain mean-field equations and obtain simulation results showing good qualitative agreement with our experimental observations.Our findings provide a novel way of overcoming the dispersion limit for simultaneous Kerr comb formation and second-harmonic generation,which might prove to be especially important in the near-visible to visible range where several atomic transitions commonly used for the stabilization of optical clocks are located and where the large normal material dispersion is likely to dominate.
