Fast measurements of laser power meters by thermal sensors using algorithms for extrapolating signals

For metrological support of the unit of average power of laser radiation, standard and working measuring instruments based on thermal sensors (calorimeters) are often used. Such instruments allow to reproduce the unit with high accuracy in a wide spectral range, as well as to carry out routine measurements of the laser power. But exist problem of application for measurements is thermal sensors is high inertia of thermal processes, which greatly increases the total time of measurements and is critical in many of applications, such as measuring the parameters of high-intensity radiation. In the paper, using the example of the thermal sensor PMT-25-50, the factors influencing the speed of sensors are considered. A method for reducing the thermal sensor time constant by optimizing the design of the thermolelemetn. However, it is not always advisable to increase the response time by optimizing the thermal sensor design. Mathematical methods for processing the thermal sensor signal are proposed to obtain a fast asymptotic estimate of the measured power. The proposed methods were tested on the PMT-25-50 and PMT-45-10K thermal sensors, which are an integral part of the laser power measurement device (developed by the All-Russian Research Institute of Optical and Physical Measurements). The paper presents the results of the study of the metrological characteristics of the PMT-25-50 sensor and its time characteristics before and after the application of the above-mentioned signal processing methods. The use of the proposed signal processing methods made it possible to reduce the time of measurements by 3-4 times. The proposed solutions are relevant in the metrology of highintensity laser radiation, which is used to control the radiation parameters of industrial lasers and laser medical equipment.

calorimeter, thermal sensor, signal processing, fast measurements, laser power meter