Polygon Coherent Modes in aWeakly Perturbed Whispering Gallery Microresonator for Efficient Second Harmonic, Optomechanic and Frequency Comb Generations

TL;DR

This paper reports the discovery of high-Q polygonal modes in a lithium niobate microresonator, enabling efficient second harmonic generation, optomechanical oscillations, and frequency combs through weak perturbation techniques.

Contribution

It introduces a novel method of forming high-Q polygon modes using weak perturbation from a tapered fiber, enhancing nonlinear and optomechanical functionalities.

Findings

High optical Q polygonal modes observed in lithium niobate microdisk.

Efficient second harmonic generation achieved with these modes.

First observation of cavity optomechanical oscillation in this system.

Abstract

We observe high optical quality factor (Q) polygonal and star coherent optical modes in a lithium niobate microdisk. In contrast to the previous polygon modes achieved by deformed microcavities at lower mechanical and optical Q, we adopted weak perturbation from a tapered fiber for the polygon mode formation. The resulting high intracavity optical power of the polygon modes triggers second harmonic generation at high efficiency. With the combined advantage of high mechanical Q cavity optomechanical oscillation was observed for the first time. Finally, we observe frequency microcomb generation from the polygon modes with an ultra stable taper-on-disk coupling mechanism.