An Axicon-Based Annular Pump Acousto-Optic Q-Switched Nd:GdVO4 Self-Raman Vortex Laser

Abstract

We report, for the first time, the generation of a 1173 nm acousto-optic Q-switched self-Raman vortex laser with an axicon-based annular pump system. A 20 mm long Nd:GdVO4 crystal was used as the self-Raman crystal. Both the fundamental field and the first-Stokes field were investigated using the respective output couplers. In comparison with both vortex fields, a noticeable beam cleaning-up effect and pulse compression were observed from the 1063 nm fundamental field to the 1173 nm first-Stokes field. A Stokes field carrying a unitary topological charge was achieved. Finally, the average output power of the first-Stokes vortex emission reached 454 mW under an incident pump power of 19.5 W, corresponding to a pulse width of 45.7 ns. It was beneficial to apply a high peak power from the Q-switched laser and self-Raman conversion to expand the applications of the vortex laser beam.

Growth, Structure, and Spectroscopic Properties of a Disordered Nd:SrLaGaO4 Laser Crystal

“…For a 1.0 µm wavelength laser, Nd 3+ -doped laser crystals exhibit high pump efficiency and a low threshold due to the long upper\-level lifetime, large emission cross section, and no reabsorption loss of Nd 3+ ions [8][9][10][11][12][13]. In recent years, many novel Nd 3+ -doped crystals have been reported to realize ultrashort or Q-switched pulsed lasers, such as Nd:GdSr 3 (PO 4 ) 3 [5], Nd:LaMgAl 11 O 19 [6], Nd:LuYPO 4 [8], Nd:Ca(Y, Gd)AlO 4 [9], and Nd:GdScO 3 [14].…”