Frontispiece: 4H-SiC: a new nonlinear material for midinfrared lasers


Nonlinear optical (NLO) frequency conversion is commonly used for generating midinfrared (MIR) lasers that offer light sources for a variety of applications. However, the low laser damage thresholds of NLO crystals used so far seriously limit the output power of MIR lasers. Shunchong Wang et al. (pp. 831–838) demonstrate a new nonlinear material 4H-SiC for producing midinfrared laser. Broadband midinfrared laser ranging from 3.90 to 5.60 μm is generated in 4H-SiC by phasematched difference-frequency generation for the first time. The results may open a door to practically utilize wide bandgap semiconductors with high laser damage thresholds as nonlinear optical materials for high power output of midinfrared lasers.