Compact Tunable External-Cavity Surface-Emitting Green Laser

By the use of a semiconductor gain chip with lnGaAs multiple quantum wells as materials in the active region and the AIGaAs/AIAs, transparent to the pump light, as distributed Bragg reflectors, along with the end pump geometry to simplify the device structure and an inserted ctalon as the tuning element, an optically-pumped compact tunable external -cavity surface-emitting green laser is realized by the intra-cavity frequency doubling technology. The employed ctalon narrows the laser linewidth as a tuning element. To prevent the second harmonic from returning to the gain chip, the ctalon is coated with a high-reflectivity film at the wavelength of the second harmonic. The tuning range of the fundamental wave is over 10 nm and that of the second harmonic is 1 nm centering at 559 nm. The spectral linewidth of the second harmonic is 1. 0 nm and the maximum output power is 65 mW.