Optical vortex beam exhibits a ring-shaped spatial profile and carries an orbital angular momentum (OAM), characterized by an azimuthal phase term, e−iℓΦ%(ℓ is a topological charge and Φ is the azimuthal angle) , and has been widely applied in a variety of fields, such as optical tweezing and manipulation, and material processing . Also, flower-shaped modes, i.e. coherent superposition of optical vortices with different OAM states also receive much attention, because their unique properties provide potentially advanced applications, including optical trapping  and quantum optics . The aforementioned applications strongly desire a versatility of wavelength and OAM state to optical vortex sources . In this presentation, we report on the first demonstration of a tunable vortex laser with versatile flower-shaped modes based on an optical vortex pumped optical parametric oscillator (OPO) formed of a non-critical phasematching LiB3O5 (NCPM-LBO) crystal in a linear cavity configuration with a cavity length of 60 mm.
© 2019 Japan Society of Applied Physics, The Optical Society (OSA)PDF Article