Study Of Real-time Measurement On Temperature Distribution Inside The Er³⁺/Yb³⁺ Co-doped Laser Gain Medium Around 1.55?m

Based on the fluorescence intensity ratio(FIR)technique,a simple and direct method of temperature measurement is proposed in this thesis,which solves the technical problem that existing methods are difficult to realize the real-time and accurate temperature distribution measurement inside gain medium when the solid-state laser is operating.The thesis consists of three parts:Thermal effect of the gain medium of a solid-state laser and its effect on the laser performance are firstly introduced in this thesis.Then,various existing technical schemes of temperature distribution measurement of gain medium are analyzed and compared in detail.In the second part,the principle of the FIR technique and the significance of temperature distribution measurement inside Er3+/Yb3+ co-doped laser crystals are described in detail.By measuring upconversion fluorescence spectra of Er3+/Yb3+:LuAl3(BO3)4(LuAB)crystal under different temperatures,the relationship between FIR of the thermally coupled levels and crystal temperature is determined.Temperature distributions inside the Er3+/Yb3+:YAl3(BO3)4(YAB)and Er3+/Yb3+:LuAB crystals are measured in the last part based on the FIR technique,respectively,while the 1.55?m laser is operating.At the same time,the influence of different laser parameters,such as incident pump power,output mirror transmission,beam waist radius of pump beam and output power,on the temperature distribution inside the crystals are analyzed and studied.