凹面光栅衍射效率测试仪精度分析和优化

Precision analysis and optimization on diffraction efficiency instrument for concave gratings

分析和优化了凹面光栅衍射效率自动测试仪的测量精度,以提高凹面光栅相对衍射效率测量结果的准确性。根据凹面光栅相对衍射效率测量原理,对凹面光栅出射光谱增宽、衍射光束截面变化、光源辐射亮度的控制和测量波长同步精度等影响测量准确性的因素进行分析,给出了必要的运算关系式。采用回归分析等数学方法,基于大量实验数据建立了测量结果的优化公式,并将该公式编入测量程序,实现了在测量结束的同时自动优化测量结果。实验表明,经过优化后的测量值更加准确,与相对衍射效率理论值的偏差均在±2.5%以内,有效提高了仪器的测量精度。该方法操作简单,无需添加或改动仪器的任何部件,可满足仪器实时性强、测量准确的要求。

This paper analyzes the measuring results of a diffraction efficiency measuring instrument for concave gratings to improve the measuring accuracy of relative diffractive efficiency. According to the testing theory of diffraction efficiency of concave gratings, the effects of the spectral broadening of exit beam for the concave grating, section changing of diffraction beam, control of light source radia- tion luminance and the synchronization precision of testing wavelength on the measuring accuracy were analyzed, and several kinds of necessary equations were given. Based on regression analysis and a large number of experiment data, an optimization equation was established and programmed into a testing programming to correct automatically the test results. Experiments indicate that the tested resuhs are correct and more precise, and the difference between optimization value and theoretical one is less than ±2.5 0/4o, which improves the testing precision effectively. This method is simpler operation, not to change the components of the instrument, and can satisfy the test requirements in strong realtime and higher precision.