High power widely tunable frequency-doubled 490 nm blue semiconductor disk laser.

This paper presents a high power widely tunable frequency-doubled semiconductor disk laser emitting at 490 nm wavelength. The laser utilizes a specially designed gain chip with widened gain spectrum at the center wavelength of 980 nm, along with an anti-resonant microcavity, to extend the tuning range of the wavelength. A type-I phase-matched 5 mm length LBO crystal is used as the nonlinear crystal, and a fused quartz birefringent filter (BRF) is introduced to polarize the fundamental emission and narrow the linewidth of the laser. When the thickness of the used BRF is 1 mm, 50.7 nm tuning range of the 980 nm infrared laser is performed. A maximum output power of 5.36 W of the frequency-doubled 490 nm blue laser is achieved, and the optical-to-optical conversion efficiency from absorbed pump power to the blue light is about 15.3%. Meanwhile, a record tuning range of 21.5 nm of the blue laser is realized. The measured M factors of the blue laser are 1.00 in the x-direction and 1.04 in the y-direction, respectively.