Theoretical And Experimental Study On Stokes' Seed Seed Solid Coherent Anti - Stokes Raman Frequency Converter

In recent years, with the development of laser technology and nonlinear frequency conversiontechnology, solid Raman laser has become a research focus in the field. The frequencyup-conversion can be achieved to expand the coherent spectrum scope and to generate coherent lightof important applications by the coherent anti-Stokes Raman scattering(CARS). The coherent lightby CARS has a wide range of application in printing, display, optical information storage. This papermainly to study the solid coherent anti-stokes Raman frequency shifter through theoretical andexperimental researching, and to explore the coherent anti-stokes Raman frequency shifter which hasthe damage threshold and simple structure, high gain coefficient, in order to produce anti-stokes lightwith high efficient conversion.This paper, we first introduce the current situation of stokes light seed Raman amplifier andcoherent anti stokes Raman laser. We study the polarization properties in PbWO4crystal. Base on theparameters of Raman crystals, we caculate the non-colinear and collinear phase-matching anglesunder different polarization configurations for Raman resonance four-wave mixing process.According to the numerical solutions for the coupled-wave equations for solid-state coherentanti-Stokes Raman shifers of the Stokes seed method, we analyze and optimize the the parameters ofthe experiment scheme of extracavity solid-state coherent anti-Stokes Raman shifers.The output properties of an extracavity PbWO4Raman laser are investigated. The extracavityPbWO4Raman laser is pumped by an actively Q-switched Nd:YAG laser.The relations between thepulse width of output Raman pulses and pumping energy are measured. The pulse waveforms ofRaman pulses are analyzed, the relations between the energy of output Raman pulses and pumpingenergy are measured, and the relations between the conversion efficiency and pumping energy arecalculated. For the extracavity PbWO4Raman laser, with an incident pulse energy of40mJ, theobtained maximum pulse energy and conversion efficiency of the first Stokes are5.8mJ and13%.When the pump energy is48mJ, the obtained maximum pulse energy and conversion efficiency ofthe second Stokes are11mJ and23%and the conversion efficiency of the full scattering laser is34%.We also present a PbWO4solid Raman amplifier. The PbWO4solid Raman amplifier is alsopumped by an actively Q-switched Nd:YAG laser. For the PbWO4solid Raman amplifier, themaximum energy of the amplification Raman pulse and the amplification factor are11mJ and3.3atthe pump energy51mJ.