Abstract
We present an extremely efficient method for generating terahertz (far-infrared) radiation by surface-emitting difference-frequency mixing in a Mie-sized crystalline microsphere that is illuminated by laser beams. A compact analytical expression for predicting the conversion efficiency is derived. With the surface-emitting scheme in which nonlinear interactions among two whispering-gallery cavity modes in the petahertz region and a scattering wave in the terahertz region are considered, problems that would arise in the strict phase matching among discrete cavity modes are avoidable. Through numerical calculations for the surface-emitting difference-frequency mixing from a LiTaO3 microsphere, dramatic enhancement of the process is predicted for certain sizes of the sphere.
© 1994 Optical Society of America
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