Highly efficient prism coupling to whispering gallery modes of a square /spl mu/-cavity

Summary form only given. We present the results of evanescent-wave coupling by using a prism to couple to a square-shaped /spl mu/-cavity (with 200 /spl mu/m edge fused silica, n = 1.456). We achieved greater than 75% energy transfer to the WGMs. The coupling efficiency and the WGM linewidth of the resonances were found to be dependent on the coupling gap as well as the angle and position of the incident light on the prism surface.