Second harmonic generation in a high-Q crystal microresonator fabricated by femtosecond laser

High-quality (high-Q) whispering-gallery-mode (WGM) microresonators can efficiently confine light in a very small volume via total internal reflection, leading to dramatically enhanced interaction of light with matter. The WGM microresonators have benefitted various applications including nonlinear optics, cavity quantum electrodynamics, quantum optics, and biosensing, etc. Due to high nonlinear optical coefficients, low intrinsic absorption loss, and large transparent window, crystalline resona