Abstract

Many technologically important applications require solid-state sources of coherent visible or mid-infared radiation. Shifting the output of existing near-infrared lasers to these spectral regions with nonlinear optical frequency conversion is a useful technique, but one which puts stringent demands on linear, nonlinear, thermal, and chemical properties of nonlinear materials. The requirement of adequate birefringence for phasematching, and the importance of noncritical phasematching, often limit the range of interactions over which a given crystal is applicable, so means for circumventing these limitations are of considerable interest. Quasi-phasematching (QPM) techniques, in which a periodic structure within the nonlinear medium, rather than a precise value of birefringence, compensates for dispersion, is such a technique.

© 1995 IEEE