Brown Steven W, Eppeldauer George P, Lykke Keith R
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Appl Opt. 2006 Nov 10;45(32):8218-37. doi: 10.1364/ao.45.008218.
Detectors have historically been calibrated for spectral power responsivity at the National Institute of Standards and Technology by using a lamp-monochromator system to tune the wavelength of the excitation source. Silicon detectors can be calibrated in the visible spectral region with combined standard uncertainties at the 0.1% level. However, uncertainties increase dramatically when measuring an instrument's spectral irradiance or radiance responsivity. We describe what we believe to be a new laser-based facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCUS) that was developed to calibrate instruments directly in irradiance or radiance mode with uncertainties approaching or exceeding those available for spectral power responsivity calibrations. In SIRCUS, the emission from high-power, tunable lasers is introduced into an integrating sphere using optical fibers, producing uniform, quasi-Lambertian, high-radiant-flux sources. Reference standard irradiance detectors, calibrated directly against national primary standards for spectral power responsivity and aperture area measurement, are used to determine the irradiance at a reference plane. Knowing the measurement geometry, the source radiance can be readily determined as well. The radiometric properties of the SIRCUS source coupled with state-of-the-art transfer standard radiometers whose responses are directly traceable to primary national radiometric scales result in typical combined standard uncertainties in irradiance and radiance responsivity calibrations of less than 0.1%. The details of the facility and its effect on primary national radiometric scales are discussed.
历史上，探测器在国家标准与技术研究所是通过使用灯 - 单色仪系统来调谐激发源的波长，从而对光谱功率响应度进行校准的。硅探测器在可见光谱区域校准后的合成标准不确定度可达0.1%。然而，在测量仪器的光谱辐照度或辐射率响应度时，不确定度会急剧增加。我们介绍了一种我们认为全新的基于激光的光谱辐照度和辐射率响应度校准设备——均匀源光谱辐照度和辐射率校准系统（SIRCUS），它被开发用于直接以辐照度或辐射率模式校准仪器，其不确定度接近或超过光谱功率响应度校准的不确定度。在SIRCUS中，高功率可调谐激光器发出的光通过光纤引入积分球，产生均匀、准朗伯型、高辐射通量的光源。直接依据光谱功率响应度和孔径面积测量的国家一级标准进行校准的参考标准辐照度探测器，用于确定参考平面上的辐照度。了解测量几何结构后，光源辐射率也能很容易地确定。SIRCUS光源的辐射特性与最先进的传递标准辐射计相结合，其响应可直接溯源到国家主要辐射测量标准，使得辐照度和辐射率响应度校准中的典型合成标准不确定度小于0.1%。本文讨论了该设备的细节及其对国家主要辐射测量标准的影响。
