基于可调谐激光的光谱辐射照度响应度定标

探测器的光谱辐射照(亮)度响应度是辐射定标中最重要的参数之一.传统的光谱辐射定标采用宽谱段光源和单色仪装置测量,新建的激光辐射测量装置采用激光和探测器测量,可以大大降低测量的不确定度.该装置首先将可调谐激光耦合进入积分球生成均匀的朗伯体单色光源,然后采用低温辐射计量传的标准陷阱探测器和面积已知的光阑,进行400～900...

Spectral Irradiance Responsivity Calibration Using Tunable Lasers

The spectral irradiance(radiance)responsivity of the detector is one of the most important parameters.Traditional spectral calibration is realized by using a broadband lamp and monochromator.The newly built facility using a laser and detector to calibrate the spectral responsivity,with the measurement uncertainty dramatically reduced.First,the facility couples tunable laser into an integrating sphere to generate a laser Lambert source.Then using standard trap detectors which can be traced back to cryogenic radiometer and an aperture with the known area,the spectral irradiance responsivity from 400 to 900 nm can be calibrated.The research is focused on four aspects:(1)Since the standard detector is calibrated at separate laser wavelengths by the cryogenic radiometer,the spectral responsivity at any other wavelengths must be interpolated.Compared with the direct measurement method using the spectral responsivity facility,the results show that the quantum efficiency difference using numerical interpolation is less than 0.074% from 400 to 900 nm.(2)In order to reduce the influence due to the laser power drift,the integrated charge method and a monitor detector are used.The charges of the standard detector and the detector under test are measured with the standard deviation of the repetition smaller than 0.1%.(3)The laser power when the standard detector is traced to cryogenic radiometer is totally different from that when the standard detector is used to transfer the spectral irradiance responsivity.Beam addition method is adopted to test the linearity of the detectors.Measurement results show that the nonlinearity correction is less than 0.025% when the current of the detector is varied from 0.2 mA to 3 nA.(4)The responsivity uniformity of the detector is measured to evaluate the uncertainty due to the difference between irradiance mode and power mode.The nonuniformity in an area of 5 mm in diameter is less than 0.03%.The uncertainty of the spectral irradiance responsivity facility from 400 to 900 nm is 0.14%~0.074%(k=1).The spectral irradiance responsivity of the detector measured by the new facility and lamp-monochromator facility is compared.Results show that the two facilities show good agreement from 400 to 900 nm.The difference between the two methods is within the uncertainty of the lamp-monochromator facility.