The polarization of the irradiance from several 1000-W FEL lamps was measured between 450 and 900 nm. These lamps are universally used as irradiance calibration standards in radiometric laboratories. The irradiance was polarized between 2.3–3.2%, with the polarization axis aligned with the coiled filament, nearly perpendicular to the lamp axis. A simple model of the filament is presented that explains the degree of polarization and the plane of polarization, based on the polarized emissivity of tungsten, and gives an approximate value for this polarization. While the irradiance is polarized, this polarization does not significantly effect the polarization of the light when reflected from a Spectralon plaque (Labsphere, Inc.). The polarization of these lamps should be taken into account when using these FEL lamps to characterize optical instruments, particularly grating spectrometers without polarization scrambling devices.
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机译：在450至900 nm之间测量了几只1000 W FEL灯发出的辐射的偏振。这些灯在辐射实验室中普遍用作辐照度校准标准。辐照度在2.3％至3.2％之间极化，极化轴与盘绕的灯丝对齐，几乎垂直于灯轴。提出了一种灯丝的简单模型，该模型基于钨的极化发射率解释了极化程度和极化平面，并给出了该极化的近似值。当辐照度被极化时，当从Spectralon斑块（Labsphere，Inc.）反射时，这种极化不会显着影响光的极化。当使用这些FEL灯来表征光学仪器，特别是没有偏振加扰装置的光栅光谱仪时，应考虑这些灯的偏振。
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