Dual-wavelength Nd:YAG Laser Based On Three Transitions Of 1052nm,1061nm And 1064nm

Dual wavelength lasers have potential applications in laser radar,precision measurement,and terahertz wave generation.Laser diode pumped solid state lasers have the advantages of high efficiency,small size and so on,and such kind of technology is an important method for realizing dual-wavelength lasers.In this thesis,the Fabry-Perot filter is used as the output mirror and the Nd:YAG crystal as the laser gain medium.By means of laser diode end pumped,three dual wavelength lasers of three wavelengths,1052nm,1061nm and 1064nm,are achieved at room temperature.We analysis the competition and coexistence relationship between these three wavelengths,this topic has a certain new meaning,and results of this study have certain reference value for the realization of the dual-wavelength laser.According to the emission spectral characteristics of the Nd:YAG crystal at room temperature,a Fabry-Perot filter is developed as a laser output mirror.Three types of dual-wavelength lasers are obtained:1061nm and 1064nm,1052nm and 1064nm,1052nm and 1061nm.The max output power is 2.02W,2.0W,1.25W,and the slope efficiency is 31%,11%,and 25.2%,respectively.Among them,the 1052nm and 1064nm,1052nm and 1061nm dual-wavelength lasers are implemented for the first time.Experiments show that the 1061nm and 1064nm dual-wavelength laser is the easiest to implement,the 1052nm and 1064nm dual-wavelength laser is the most difficult to implement,and the 1052nm and 1061nm dual-wavelength laser is in the middle.On the one hand,the emission cross sections at 1052nm,1061nm and 1064nm are quite different,and on the other hand,they depend on different energy levels involved in the laser transitions.The Stark energy levels corresponding to the 1052nm,1061nm and 1064nm transitions are(R2-Y1),(Ri-Yi)and(R2-Y3)respectively.The 1061nm and 1064nm transitions have different upper and lower energy levels,the competition of inversion particle amount is not direct;the 1052nm and 1061nm transitions have different upper level and the same lower level,the lower level is the lowest in the degenerate level,and the competition is fierce;the 1052nm and 1064nm transitions have the same upper energy level and different lower energy level,the two lines share the inverted population of the stark energy R2,and the competition is most intense.The results of the study indicate that when implementing a dual-wavelength laser,it is best to choose the transitions that involve different upper and lower energy levels.It is found that the conditions for the coexistence of three lines of 1052nm,1061nm and 1064 run are that the thresholds of these three wavelengths are similar and the 1052nm line threshold less than 1061nm line threshold less than 1064nm line threshold.The two lines of 1052.1nm and 1064.17nm jointly consume the number of inversion particles on the stark level R2,and the competition between these two lines is fierce.When the pump power is high,the 1064.4nm line appears near the center wavelength of 1064.17nm due to the thermal effect of the gain medium and the spatial burning hole effect.1061.5nm line and 1064.4nm line share the inverted population at the Stark energy Ri.Meanwhile,intense competition happened between these two lines.With the increase of the pump power,the 1064nm line will eventually win and exist alone,ie,the three wavelengths of 1052nm,1061 nm and 1064nm can only coexist within a certain range of pump power.