A 234nm Deep Ultra-violet Laser Based On An Optical Parametric Oscillator

Ever since the first laser has been realized,laser technology is advancing at a breathless pace and Optics has become one of the most popular areas of scientific research.The standard calibration of the seven fundamental quantities in physics has always been the most significant part in fundamental physical research.In order to build a time-frequency standard,our research group is sparing no effort to set up an Al~+optical clock.Due to the lack of 167 nm CW cooling laser,we cannot directly cool down Al~+.Here we propose a new way to directly cool down Al~+instead of sympathetically cooling by cool down some other ions first.According to the requirement,we gave a preliminary result at the aimed wavelength.The detailed work in this thesis mainly includes:1.A mathematical-physical model was built up using the Matlab software based upon the nonlinear optics theory.We simulate the evolution of laser pulse affected by the nonlinear crystal in an OPO cavity during every iteration.At the same time,a periodically poled lithium niobate(PPLN)crystal was designed to suit the proposed projects.2.A FROG device was set up to measure the properties of an ultrashort laser pulse in both time and frequency domains.A Matlab program was written to deal with the experimental data to generate a FROG trace that can be computed by the FROG retrieve program.Besides,the optical path of the FROG was integrated into a portable device.3.Set up an OPO,consisting of six cavity mirrors and two focuses,so that a BBO crystal can be inserted in the OPO cavity.The OPO operates at 250 MHz and it can generate 1.43 W 851 nm laser.Besides,highest conversion efficiency reaches 20.8%.To our knowledge,it is the highest efficiency operating at such a high repetition rate OPO with intracavity frequency doubling process.4.The sum frequency generation(SFG)of the OPO output and the source laser was generated.This SFG is a 468 nm blue laser,the highest power of which is 158 mW.The second harmonic generation(SHG)of the blue laser is obtained and a 2.6 mW 234 nm laser is observed.