Research On The Calibration Method Of Wide Spectrum Detection Efficiency Of Correlated Photons Radiation Benchmark

The correlated photons radiation benchmark can obtain the system responsivity in real time on the space platform,without any standard or standard transfer chain.It has broad application prospects in climate monitoring,on-board calibration and other fields.However,the traditional satellite remote sensor calibration technology lacks high precision radiation benchmark.And the sensor performance is prone to decay in the space environment.The calibration accuracy and stability of the current remote sensor satellite calibration are difficult to meet the requirements of quantitative application and climate change research.In order to deal with such problem,the broad spectral irradiance principle prototype based on correlated photons radiation benchmark is developed.Note that,the principle prototype has two modes at work:self-calibration and radiation observation,respectively.The self-calibration mode obtains the channel detection efficiency of the principle prototype through the correlated photons radiation benchmark.Then,the radiation observation mode obtains the absolute irradiance of the target light source based on the channel detection efficiency and the deduced irradiance equations.According to the absolute irradiance measurement principle,a high precision of wide spectrum absolute irradiance measurement relies on two points:the preparation of continuous wide spectrum correlated photon source and the channel detection efficiency calibration.Therefore,the main work of this thesis is summarized as follows:In order to meet the performance requirements of the prototype,the correlated photon source with continuous wide spectrum is prepared.The design scheme of correlated photons radiation benchmark is demonstrated.Then,the effects of pump wavelength,crystal phase-matching angle and focusing lens length during spontaneous parametric down conversion related to the characteristics of correlated photon source are analyzed.Theoretical analysis and numerical simulation about the distributions of correlated photon spectral,radiation angle and photon count rate were carried out,where a wide spectrum high-flux correlated photon source,range from 380 nm～2500 nm,is prepared.The correlated photons spectrum and photon count rate are measured from 380 nm～1000 nm and the corresponding temporal correlation is calculated from 386 nm～1600 nm.According to the wavelength correlation of the correlated photons,the wide spectrum distribution characteristics from 380 nm～2500 nm are verified.By investigating the relationship between the spatial distribution of correlated photons and non-collinear angle,spectrum and other parameters,we construct a theoretical model including correlated photon ring,non-collinear angle,divergence angle and other parameters,where the measurement device is built.The deviation range of non-collinear angle is from 0.0235°～0.2032°,providing the parameter guidance for the design of the prototype optical system.In order to improve the calibration accuracy of wide spectral channel detection efficiency,the cut-off effect of optical components on pump light is analyzed and the suppression scheme of pump light is proposed.The value of optical density in the filter system is greater than 10.5,ensures the signal-to-noise ratio of the photon detector.In this thesis,the quantitative relationship between the measurement uncertainty of detection efficiency and various parameters during the process of correlated photon calibration is built,the theoretical model is proposed to explore the relationship between the measurement uncertainty of detection efficiency and photon counting rate,measurement time and detection efficiency.A confirmatory experimental device is also built to verify the performance of the proposed theoretical model.Results shows that the deviation range between theoretical simulation and experimental measurement results is in the range from 0.002%～0.81%.Based on the theoretical model,the experimental parameters of the correlated photon calibration are set,where the test and analysis of the principle prototype are conducted.The detection efficiency of the principle prototype is calibrated,and the effects of correction factors such as dead time,afterpulse and bandwidth on the detection efficiency calibration results are analyzed.Results show that the measurement uncertainty of channel detection efficiency is better than 0.2%.In this thesis,the correlated photon source with wide spectrum is prepared to meet the performance requirements of the absolute irradiance principle prototype and the high precision calibration of the detection efficiency of continuous wide spectrum is achieved.Such thesis can provide a theoretical reference and experimental basis for the further development of the correlated photon radiation.