Theoretical And Experimental Study Of All Solid State Intracavity Sum-frequency Raman Yellow Laser

The discovery of Stimulated Raman scattering(SRS) provides a practical method to generate laser output of different frequencies. In recent years, the research of Raman lasers is still very popular, because many Raman crystals of excellent performance have been found due to the progress of crystal growth technology, and provide the possibility of further research on SRS. For different combination of laser media and the Raman crystal,the wavelength range of first Stokes which is produced from Raman laser can spread from purple to near infrared wavelength. The study of all solid state Raman lasers has now become a very attractive forefront field for researchers. All solid state Raman lasers has advantages of compact and convenient construction, high efficiency, and less susceptible to outside interference. In the area of traffic, communication, medicine, surveying and mapping, the national defense and so on, all solid state Raman lasers have important applications.The yellow green laser of 560nm~600nm has many applications. In the area of algae red protein markers, biological immune detection, medical equipment application,biochemistry technology, yellow-green lasers has important applications. The 560 nm laser has been extensively used. How to obtain the laser efficiently is always the main of the laser researchers. Second harmonic generation(SHG) and sum frequency generation(SFG)are two effective ways to generate yellow green laser. There are few laser materials that can generate the laser of 1120nm~1200nm directly, so it is difficult to generate laser of560 nm ~ 600 nm through SHG. The Raman laser provides the possibility for SHG and SFG to generate the yellow green laser.The paper first introduces the classification and research status of all solid state Raman lasers, as well as the research situation of sum-frequency Raman yellow laser. The paper also introduces the Raman crystals and sum-frequency crystals.The paper takes rate equations as research tools, and rate equations of the passively Q-switched intracavity sum frequency Raman laser and actively Q-switched intracavity sum frequency laser are deduced, respectively. The rate equations are normalized, and thenormalized comprehensive factors are introduced. The parameters of common used crystals are adopted to calculate the reasonable value range of the comprehensive factors.With the appropriate values, the numerical simulation of the normalized rate equations is carried out, and the influence of the parameters on the laser pulse is studied. The simulation results can be used to guide the design of the Q-switched intracavity sum frequency Raman lasers. Based on the theoretical study, the diode laser pumped passively Q-switched Raman laser is designed. The Sr WO4 Raman crystal is used. When the input pump laser power is 4.12 W, the maximum output power of the Raman laser reaches0.724 W, and the Raman conversion efficiency is as high as 17.5%. The experiment results reflect the excellent Raman characteristics of SrWO4 crystals. Parameters of optical elements which influence the Raman laser output power are analyzed, including the input mirror curvature radius, saturated absorber initial transmittance and the reflectivity of the output mirror.In this paper, the sum-frequency properties of KTP crystal are studied, and the passively Q-switched intracavity sum-frequency Raman yellow laser are designed and experimented. The yellow green laser is obtained. When the input pump power is 4.12 W,the maximum output power of sum-frequency yellow green laser reaches 0.109 W, the conversion efficiency is 2.64%, the pulse width is 6.5ns, the single pulse energy is 19.9?J,and the peak power is 3.06 kW.