Progress and applications of VECSELs: The most versatile laser platform

Vertical-external-cavity surface-emitting lasers (VECSELs), also referred as semiconductor disk lasers (SDLs), have emerged at the frontier between solid-state and semiconductor laser technologies. Therefore, these high-brightness light sources draw important advantages from both semiconductor and solid-state lasers: the simplicity to engineer the emission properties of semiconductors is combined with the functionality of solid-state lasers owing to the use of external cavity architectures. This combination has enabled obtaining outstanding results in terms of wavelength coverage (from visible to mid-IR), high-power (100W-level), single-frequency operation, efficient intracavity frequency conversion, and ultra-short pulse generation (down to sub-picosecond range with GHz repetition rate). Moreover, the low-cost of broad-area diodes used to pump the VECSELs and the broad-band pump absorption, have made the optically-pumped-VECSELs practical and cost effective.