Tunable ultraviolet and blue light generation from Nd:YAB random laser bolstered by second-order nonlinear processes

Ultraviolet and blue light were obtained by nonlinear frequency conversion in a random laser (RL) based on Nd 0.10 Y 0.90 Al 3 (BO 3 ) 4 nanocrystalline powder. RL operation at 1062 nm, due to the 4 F 3/2 → 4 I 11/2 transition of neodymium ions (Nd 3+ ), was achieved by exciting the Nd 3+ with a tunable beam from 680 to 920 nm covering the ground state absorption transitions to the 4 F 9/2 , ( 4 F 7/2 , 4 S 3/2 ), ( 4 F 5/2 , 2 H 9/2 ) and 4 F 3/2 states. Light from 340 to 460 nm was obtained via the second-harmonic generation of the excitation beam while tunable blue light, from 417 to 486 nm, was generated by self-sum-frequency mixing between the excitation beam and the RL emission.