Efficient Vortex Laser With Annular Pumping Formed by Circle Dammann Grating

We proposed and demonstrated an efficient vortex Nd:YVO4 laser under the utilization of a circle Dammann grating (CDG). As a simple binary-phase component, CDG was inserted into the pump unit of this laser-diode end-pumped solid-state laser and reshaped the pump radiation into annular profile with high efficiency. Moreover, such utilization of CDG avoided additional modification to laser cavity. As a result, the laser emitted vortex beam with a high slope efficiency of 51% and a maximum beam power of 554 mW at 1.75-W incident pump power.