Research On The Generation And Phase Control Technology Of Vortex Light Field

With the development of optical technology,it is found that light as a carrier of information and energy has natural advantages,so the control of light field is particularly important.Vortex beam is a kind of special beam with helical phase wavefront and annular intensity distribution.It is widely used in optical micromanipulation,super-resolution imaging and the interaction between light and matter.In order to further explore the potential application value of vortex light field,the flexible control of amplitude,phase and polarization of vortex light has gradually become a new research hotspot in recent years.This paper focuses on the generation of vortex light field and its phase and polarization control technology.Firstly,a method of generating multi fractional perfect vector beam(MFPVB)based on holographic beam shaping technology is studied.This method is based on the traditional fractional order vortex optical field,combined with the concept of perfect vortex and multi fractional order vortex,by inserting multiple fractional phase jumps evenly on the spiral phase plate,the phase distribution of multi-mode fractional order perfect vortex beam is designed,and then by coaxial superposition of two scalar multi fractional perfect vortex beams,the multi fractional perfect vector light field with unique polarization state distribution is obtained.Secondly,a simple generation method of tunable multi ring perfect optical vortex(MR-POV)is proposed.By introducing a controllable phase jump along the radial direction,a perfect optical vortex with multi ring structure is generated on the Fourier plane.This kind of vortex beam has many compact rings whose diameter is independent of topological charge,and still satisfies the definition of perfect vortex beam.Taking the double ring model as an example,the characteristics of MR-POV are analyzed.Through interference experiments,it is proved that each ring has the same topological charge.By adjusting the phase difference between the adjacent rings,the light intensity ratio between the rings can be adjusted freely.Finally,we propose a method to measure the topological charge of vortex beam by using elliptical Airy phase mask.By analyzing the number and direction of dark fringes in far-field diffraction pattern of vortex beam modulated by elliptical Airy phase mask,the absolute value and sign of topological charge are obtained respectively.The experimental results show that the method does not need to adjust the measurement phase,and does not need complex calculation process.It is univers al for both traditional vortex beams and perfect vortex beams with topological charge less than ±120.This technique can be used in various vortex related applications,such as optical tweezers,complex beam shaping and optical communication.In addition,it is also enlightening for other applications of Airy beam.