Dual-frequency wavelength-tunable blue–green laser system for undersea applications

A dual-frequency, wavelength-tunable blue-green laser system is demonstrated. The system utilizes a high-energy 532-nm green laser to pump a KTiOPO_4 (67.8^\circ, 0^\circ) optical parametric oscillator followed by a LiB_3O_5 (90^\circ, 22.5^\circ) second harmonic generator, generating blue laser light tunable from 447.6 nm to 459.7 nm with an overall frequency conversion efficiency of 4.2%. Both the residual green laser and the tunable blue laser can be emitted simultaneously, with energies of 11.24 mJ and 0.92 mJ, respectively. The beam quality factors M^2 of the green and blue lasers are M^2(x,y) = (18.7, 12.6) and M^2(x,y) = (29.5, 11.0), respectively, with corresponding energy stabilities of 6.1% and 13.9%. The blue laser pulse width is 6.84 ns, yielding a peak power of 134 kW. This laser system offers potential for various undersea applications where adaptable wavelength tuning is essential.