Study On The Mechanism And Control Method Of Hollow Cone Light Produced By Biaxial Crystal

The phenomenon of hollow beam produced by conical refraction of biaxial crystal has been noticed since the beginning of the 19 th century.With the continuous development of laser technology and the application of advanced technology such as synthetic crystal,people are interested in the convergence and deformation of laser beam mode by conical refraction.According to the cone refraction theory,if a laser beam propagates along one optical axis of biaxial crystal,it will produce hollow cone light.The energy distribution characteristics of the hollow conical light make the hollow conical light have the advantages and application prospects that the solid laser can't compare,such as the scalable characteristics of the hollow conical light,which makes it different from the solid light in principle in scanning point by point,line by line,with the advantages of fast scanning speed and wide scanning range.The hollow conical light can be used for multitarget detection and multi-purpose As a result,the hollow conical light is widely used in printing,scanning,copying,radar,guidance,communication,disease diagnosis and other industrial,medical and national defense fields.Therefore,this special phenomenon of biaxial crystal has always attracted the attention of many researchers.But up to now,because of the crystal structure and characteristics of the hollow conical light and the cone angle control and output characteristics of the hollow conical light have not been studied in theory and experiment,so until now,the hollow conical light has not been applied in practice.Therefore,we do theoretical analysis and Experimental Research on the generation and output characteristics of the hollow conical lightTo explain the birefringence phenomenon of biaxial crystal,the plane wave solution of Helmholtz equation of biaxial crystal is studied.When the crystal produces Bessel beam or cone beam,the method based on electric field vector is used to solve it.The fourth-order algebraic equation of the fourth-order wave number is derived,and the paraxial approximation is precisely studied by Ferrari method,and the simple extension of cone diffraction integral equation is obtained.For the hollow beam produced by biaxial crystal,in addition to defining general parameters,several special parameters are needed to characterize the radial intensity distribution of the hollow beam.Several methods of producing hollow beams areintroduced and their mechanism is studied.It paves the way for the following experiments and analysis.By using the generated Laguerre Gaussian beam to further study the hollow beam,we can realize the analysis of biaxial crystal from birefringence to Laguerre Gaussian beam.By adjusting the angle of crystal,we can adjust the observed beam,and then analyze the characteristics of conical refraction.For the case of different diffraction counts,the hollow beams have different characteristics.This work is of great significance to promote the application of hollow conical light.