Optical Supercontinuum Generation via Rotational and Vibrational Molecular Cavity Optomechanics

The solid high quality (Q) factor whispering gallery mode microcavities are demonstrated as an excellent experimental platform for enhanced light-matter interactions, and are applied in the studies of nonlinear optics, quantum optics, and sensing. However, the interaction between the microcavity and liquid anisotropic molecule, which is unique for abundant vibrational and rotational degrees of freedom, is rarely studied. Here, the gap is bridged by filling an optofluidic microbubble resonator with carbon disulfide, and the related anisotropic molecular cavity optomechanics effects are investigated. Due to the enhanced coupling between the optical mode and the rotation/vibration of molecules, stimulated Rayleigh-Kerr/Raman-Kerr scattering effects are observed. Molecular cavity optomechanics provides a broadband gain for generating Stokes photons in high-Q optical modes, and eventually allows quasi-supercontinuum generation with a bandwidth of 436 nm under a low continuous laser pump power of about 10 mW. This work opens a new avenue for strong light-matter interactions by exploring rotational and vibrational molecular cavity optomechanics, which provides a promising platform for nonlinear optics, cavity-enhanced molecular reorientation dynamics, and novel optical sources.

Automated summary

This study investigates the interaction between a microcavity and liquid anisotropic molecules by filling an optofluidic microbubble resonator. Enhanced coupling between the optical mode and the rotation/vibration of molecules leads to the observation of stimulated scattering effects and the generation of quasi-supercontinuum.