Second harmonic generation (SHG) from hyper-Rayleigh scattering (HRS) in a hybrid strong coupling micro-cavity waveguide (HSCMW) was demonstrated, which indicates a possible method using continuous-wave (CW) incident light. The CW light was coupled into the waveguide with high coupling efficiency by free space coupling technology, and then the electric field intensity of fundamental wave was enhanced due to local oscillation.

HRS was occurred by lithium niobite (LN) powder inside the waveguide, resulting in direct observation of SHG in the transverse direction, with relatively high conversion efficiency measured to be 0.032%/W. This work suggests a progress on frequency conversion and is also applicable to other nonlinear processes in waveguide.

Fig. (a)-(f) The structure and the E distribution of hybrid strong coupling micro-cavity waveguide; (g) Experiment systems and equipment.

This research has been published in “Beiyi Zhang, Hailang Dai and Xianfeng Chen, Hyper-Rayleigh scattering in a strong coupling micro-cavity waveguide, Opt. Lett. 46(3), 584-587(2021)”

Link：https://doi.org/10.1364/OL.411384