Study Of Dual-wavelength Raman System And 578.5 Nm Yellow Laser Based On Yb:YAG/Cr⁴⁺:YAG/YAG Composite Crystal

With the development of laser technology,it has been widely used in military,industrial,medical,communications and other fields.In some important application such as terahertz wave,differential absorption lidar,laser display,blood detection and spectral analysis,dual-wavelength laser is needed as the input light source.At present,some dual-wavelength lasers have been reported are defective because of its complex structure and high cost.Therefore,this paper design and build a simple structure,low cost and efficient dual-wavelength laser in this paper,which have application value.Yellow light laser has been widely used in medical,remote sensing and communications.The578.5 nm laser has been used to make optical atomic clocks and to study basic physics.It's Pulse output has significant function in treating skin diseases and eye diseases because it's under the absorption band of hemoglobin.Most of the 578.5 nm yellow laser has been reported output the continuous light,and the power is generally around dozens of milliwatts.In this paper,a relatively simple structure of hundred-milliwatt-level passive Q-switch 578.5 nm laser system has been designed.This paper includes the following experimental research contents and results:1.The fundamental wave properties of Raman lasers based on Yb:YAG/Cr⁴⁺:YAG/YAG composite crystals are measured and discussed.It is concluded that when the transmittance of the output mirror to 1030 nm is 20%,the slope of the fundamental wave is the highest.When the pump power is 17.21 W,the dual-wavelength fundamental's totally power is 5.12 W and the slope is 38.24%.2.In the experiment of dual-wavelength Raman laser based on Yb:YAG/Cr⁴⁺:YAG/YAG,the slope efficiency is 10.53%when the output mirror transmittance T_OC2=10%,and the totally maximum dual-wavelength power is 1.013 W when the input pump is 12.69 W.At the maximum power,the corresponding repetition frequency,pulse width,pulse energy and pulse peak power are 6.28 KHz,9.90 ns,157 J and 15.8 KW,respectively.3.The 1157 nm single wavelength Raman laser based on the composite crystal has been designed.The stable output of single wavelength Raman laser can be achieved by inserting F-P etalon in the cavity and the 1157 nm wavelength account over 92%of the output spectrum.When the input pump power reaches 9.87 W,the average output Raman power reaches the maximum of0.784 W,the conversion efficiency is 7.94%,and the slope efficiency is 11.29%,the maximum repetition frequency and the pulse width are 5.52 KHz and 6.5 ns,respectively.4.At the end of this paper,a yellow laser with a slope efficiency of 2.67%and a threshold of3.77 W has been obtained by adding a middle plate and a frequency doubling crystal on the basis of a single wavelength Raman laser.When the input power reaches 9.51 W,the maximum output power is 183 mW.The experimental results show that the design of all-solid double-wavelength Raman laser and578.5 nm laser is reasonable and feasible,which means these lasers have application value.