Researches On Orthogonally Polarized Dual-wavelength Passively Q-switched And High-repetition-rate Self-mode-Locked Vortex Laser Generation Based On Pr3+-doped Lasers

In 1989,French physicist P.Coullet proposed such a light field,which has properties similar to vortices in fluid dynamics,and named it optical vortices.In 1992,the most important property of vortex beam,namely carrying orbital angular momentum(OAM),was discovered by British physicist L.Allen.The typical representative of this type of beam is the Laguerre-Gaussian(LG)beam.The concept of optical orbital angular momentum has rejuvenated the powerful vitality of vortex beam in theoretical exploration and practical applications.Vortex beam has great application value in the fields of optical communication,quantum entanglement,new nonlinear optical effects,micro-nano machining,super-resolution imaging and optical tweezers.This thesis first introduces the concept and application value of the vortex beam,secondly,the thesis summarizes the basic optical theory,then,starting from the application of the vortex beam and the orbital angular momentum,We report on direct generation of an orthogonally polarized dual-wavelength vortex laser,for the first time to our knowledge,by means of a diode-pumped V-shaped Pr:YLF laser platform,finally,a cylindrical lens is used to realize a high-frequency self-mode-locked vortex laser by designing a simple flat concave cavity.The specific research contents are as follows:The first chapter mainly discusses the concept and application value of the vortex beam,and summarizes the methods of generating and measuring the vortex beam,and finally gives the development history of the vortex beam,including the domestic and foreign research status of the vortex beam.The second chapter mainly deals with the analysis of resonant cavity laser theory.Firstly,the vortex beam threshold theory is discussed,then,the orthogonally polarized dual-wavelength laser theory is analyzed,finally,we discuss the theory of the nonlinear characteristics in the self-mode-locked laser.The third chapter is mainly about the experiment of orthogonally polarized dual-wavelength vortex laser.The research work includes the following aspects:In Pr:YLF laser resonator,(1)Slightly misaligning the folded mirror is proposed to realize the simultaneous orthogonally polarized dual-wavelength laser,(2)The vortex beam is directly obtained by orthogonally rotating the laser gain medium;(3)With the help of Co:ASL saturation absorber,we not only realized the continuous laser but also abtained the passively Q-switched vortex lasers at single-and dual-wavelength orange laser emissions.The fourth chapter,the main research content is about the experimental design and performance realization of high-frequency self-mode-locked vortex laser.The research work includes the following aspects:(1)The laser resonator uses a simple flat concave cavity,(2)By adjusting the length of the laser cavity,fine-tuning the input and output cavity mirrors and crystal angle,it is directly generated the high-frequancy self-mode-locked Hermite-Gaussian vortex laser in the resonator,(3)Finally,the double-cylinder lens is used as a mode converter to convert the HG mode to the corresponding LG mode,so as to realize a high-frequancy self-mode-locked vortex laser outside the cavity.