[11a-N307-1~9] 4.7 Quantum Optics and Nonlinear Optics

▲ [11a-N307-8] Direct generation of green vortex from a Pr:YLF laser by an optical needle pump geometry

〇(M1)Taku Miike¹, Takuya Morohashi¹, A Srinivasa Rao^1,2, Katsuhiko Miyamoto^1,2, Takashige Omatsu^1,2 (1.Chiba University, 2.MCRC)

Keywords:orbital Poincare laser, Green Vortex beam, Pr:YLF laser

Optical vortex has been receiving tremendous interest in a wide range of applications such as fluorescence microscopy with a high spatial resolution beyond the diffraction limit, optical manipulation, and materials processing. In general, visible green vortex laser sources largely rely on the frequency doubling of infrared vortex modes. However, such nonlinear frequency conversion impacts frequently the quality of generated vortex modes owing to the doubled topological charge and undesired coherent mode coupling. Here, we report on the first demonstration of an ultra-compact green vortex Pr:YLF laser source by employing an off-axis optical needle pumping geometry and without nonlinear frequency extension. Our system without any additional optical elements for wavefront modulation should open the door towards new advanced bio-imaging and microfabrication technologies. The generated green optical vortices, mapped on an orbital Poincaré sphere, exhibit a maximum output power of ~300 mW at a slope efficiency of 12%.