Research On High-precision Temperature Detection Technology For Laser Calorimetry

In the measurement of absorption loss of optical components by laser calorimetry system,the high-precision temperature detection module is one of the key modules,and the accuracy of temperature detection determines the accuracy of absorption loss measurement of optical components.Based on laser calorimetry technology,a highprecision temperature detection system applied to laser calorimetry system is designed in this thesis,which can be completed the high-precision real-time measurement of the temperature of the calorimetry system.The high-precision temperature detection system based on laser calorimetry technology is studied in this thesis,and main works completed as follows:1.The common absorption loss measurement techniques are introduced,and the laser calorimetry technology is highlighted.Since the temperature detection module is one of the key module in the laser calorimetry system,the common temperature detection techniques are introduced,and the contact temperature measurement method used in the laser calorimetry system is emphatically introduced.After analyzing various temperature sensors,a negative temperature coefficient sensor is selected as the temperature sensing element and a bridge circuit is used as the temperature measurement circuit by comparing the temperature measurement range and temperature measurement accuracy of various temperature sensors.2.Modeling and simulating of the optical component and temperature sensors used in laser calorimetry technology,and analyzing the factors affecting the temperature field of optical component,including different sensor spacing,heat flux power,heat flux injection area,heat flux injection location,as well as the overall offset distance between the temperature sensor and the heat flow load surface.Requirements are placed for the relative position of the temperature sensor and the optical element in the calorimetric system,and the heating laser power conditions.3.The hardware circuit design of the temperature detection circuit with variable gain control for self-balancing bridge based on ambient temperature compensation is completed,and the schematic diagram and PCB board diagram are drawn,in which the variable gain can meet the needs of different temperature measurement ranges and temperature measurement accuracy.The software design of the circuit is completed which mainly contains the self-balancing adjustment and temperature measurement functions,and the function control can be completed by programmed command control.4.The construction of the simulation experimental system is completed,and the measurement structure of the constructed system is modeled and simulated.The simulation temperature calibration and simulation measurement are completed.5.Based on the principle of compressive sensing,two methods are proposed to complete the surface temperature detection using single-point temperature sensors,which are two new methods different from the traditional detection of surface temperature using matrix temperature sensors.