实际光栅系统的分辨本领

Resolving power of actaul grating system

本文指出了传统的光栅分辨本领Ｒ＝ｋＮ只是在光源狭缝无限细的情况下的极限值。当光源狭缝还有一定宽度Ｗ时，衍射条纹将增宽，相应最小分辨角Δθｋ将增大，实际光栅系统的分辨本领将减小。文章运用衍射理论，给出了实际光栅系统分辨本领的修正公式。在实验中，在不同光栅宽度Ｄ的情况下，用ｋ＝１级衍射条纹，当测量恰能分辨钠黄光的双线结构的光源缝宽Ｗ时，这时光栅系统的分辨本领是λ／δλ≈１０００，与修正公式计算的理论值一致。

The paper points out that the resolving power of grating in tradition, R=kN, is just the limit value only when the slit of light source is infinitely thin. When the slit of light source there is definite width W, the width of diffraction fringe should increase, and the minimum resolving angle Δθ k should be increasing, then the resolving power of actual grating system should be decreasing. This paper applies diffraction theory, has given the corrected formula of the resolving power of actual grating system. In the experiment, under the conditions of different grating widths D, as k=1 diffraction fringes of the tow lines of natrium light are just right resolved, measure the slit widths W of light source, when the resolving power of actual grating system should be λ/Δλ≈1000, its in keeping with the theoretical value of the corrected formula.