Design Of Tunable Single-frequency All-solid-state Laser For Absolute Distance Measurement By Linear Frequency Tuning

Linear frequency tuning continuous-wave laser ranging has the advantages of large measurement range,high accuracy and high resolution,it has been widely used in used in large-scale industrial measurement,lidar detection and other fields.The key to the linear frequency tuning continuous-wave laser ranging system is to obtain a wide-band linear frequency tunable laser source,the performance of the linear frequency tunable laser directly affects the accuracy of the measurement system.At present,semiconductor lasers or microchip solid-state lasers are mostly used as light sources for linear frequency tuning ranging.In this thesis,the design and experimental research work of tunable single frequency all-solid-state laser with twisted-mode cavity is carried out.The laser has the advantages of low cost and easy frequency tuning,which lays the foundation for the exploration and development of new linear frequency tunable ranging instruments.In the absolute distance measurement of liner frequency tuning,the laser output is required to be a stable single frequency mode and continuous linear frequency tuning,so a tunable single-frequency all-solid-state Nd:YAG laser based on twisted-mode cavity has been designed and studied in this thesis.Firstly,the mode theory of the laser was analyzed,the common methods of single longitudinal mode selection of laser were studied,and the experimental system of single-frequency all-solid-state laser based on the principle of twisted-mode mode selection was constructed,and the linearly polarized 1064nm single longitudinal mode laser oscillation output was realized.Secondly,the linear frequency tuning characteristics of 1064nm single longitudinal mode laser were studied,the relationship between the linear frequency tuning range and the length of the laser cavity was simulated and analyzed,the single frequency laser linear frequency tuning scheme was designed,and the PZT driving source required in the scheme was designed to drive the laser cavity length with high precision.Finally,the laser cavity length changes linearly drive the laser cavity length with high precision.Finally,the laser cavity length changes linearly by applying an amplitude-adjustable DC voltage to the PZT,thereby achieving linear tuning of the laser frequency.In the thesis,an experimental system of LD-pumped tunable 1064nm single-frequency Nd:YAG laser based on the principle of twisted-mode cavity selection was established.The characteristics of the laser such as oscillation,polarization,power output and liner frequency tuning were experimentally studied.The results show that the maximum output power of the laser is 119mW with a linearly polarized single longitudinal mode laser.When the linear tuning amount of laser cavity length is 0.266?m,the linear tuning amount of laser frequency reaches 2.5GHz,and the frequency tuning sensitivity is 0.166GHz/V.