Fused-silica monolithic total-internal-reflection resonator

We have characterized a miniature fused-silica monolithic optical ring resonator in which the Gaussian mode is confined by total internal reflection. Laser light is coupled into and out of the resonator by frustrating one of the total internal reflections by means of a prism. The resonator can be overcoupled and undercoupled by varying the resonator–prism distance. The minimum measured resonator linewidth was less than 3 MHz. This type of broadband, stable, low-loss resonator has applications in linear and nonlinear optics.