Study On Direct Generation Of Vortex Laser By Rotating Induced Off-axis Pumping

Vortex beam propagates in the direction of wave propagation in the form of helix,so the central light intensity is zero,and it is also called the dark hollow beam.In the transmission process,vortex momentum has both linear momentum and orbital angular momentum.It provides a new way and information for the optical information processing of vortex beam.At this stage,it is still a difficult and hot spot to study how to obtain high power vortex laser with the simplest method to accurately measure the angular momentum of the orbit.In this paper,on the basis of all solid state laser generation technology,a kind of laser gain crystal in two orthogonal directions is proposed.The off-axis pumping of the laser crystal will lead to the control of the transverse mode field in the cavity,thus producing the output of the vortex laser.The control of the transverse mode field in the cavity is based on the pattern matching principle of the laser resonator.By rotation of the gain medium in the resonant cavity to suppress the oscillation of the Gauss base mode in one direction,the ermim Gauss mode is generated,and then the gain medium is rotated in another orthogonal direction,resulting in two direction eras.The superposition of the rice Gauss mode eventually leads to the formation of Laguerre Gauss mode.The Laguerre Gauss mode field has vortex phase and is a vortex beam.The output of the vortex optical chirality can be controlled by adjusting the output coupling mirror or inserting a low loss glass sheet.Compared with the existing methods of producing vortex laser based on solid laser technology,the greatest characteristics of the vortex generation method proposed in this paper are simple,easy to realize,low threshold,high output power and high efficiency.On the basis of the Fizeau interferometer,an improved scheme is proposed to verify the output vortex optical rotation.The scheme is composed of only one focusing lens and a plated flat concave lens.Compared with the traditional M-Z interferometer verification scheme,the proposed scheme is simple and does not need to build relatively complex M-Z interferometer optical path.In conclusion,the complete set of vortex light generation and verification device in this paper provides a new method and way for the simple and efficient acquisition of high power vortex laser and the determination of vortex chirality.