Recent developments in high-power two-wavelength vertical external-cavity surface-emitting lasers

Two-color, high-power, tunable lasers are highly beneficial for the generation of new wavelengths through various nonlinear methods. Vertical external cavity surface emitting lasers (VECSEL) are particularly flexible for intracavity wavelength control. We report a novel VECSEL cavity capable of generation high-power, tunable, two-color generation. The laser employs overlapping VECSEL cavities in a two-chip T-shape cavity configuration which uses a polarizing beam splitter/combiner to fold one cavity and thus allows for two-color orthogonally polarized high power outputs. The tunable collinear, orthogonally polarized two-color is ideal for type II nonlinear conversion. A continuous wave (CW) output power in excess of 13 W for the two-color emissions was demonstrated to be the sum of the output from each of the overlapped cavities. In a high Q cavity, birefringent filters were used to facilitate tunability, and wavelength separation was varied from 35 nm to 52 nm. In a modified T-Cavity configuration, high power intracavity type-II sum frequency generation resulted in tunable blue-green emission with more than 750 mW output. By selecting identical or different chips in the cavity, the wavelength separation and tuning can cover a wide range from zero to several hundreds of nm opening doors for broad mid- to far-infrared applications.