利用最小偏向角测量谱线波长

在利用光栅测量谱线波长的实验中,常用自准直法保证光线垂直入射。由于光栅玻璃的两个面都反射,从望远镜中看到的绿十字像是重影像,无法精确调整。分光计可以比较方便的测量相应衍射线与入射线的夹角即偏向角。本文先证明了在斜入射情况下,偏向角存有一最小值,再通过测量最小偏向角来测量谱线波长。

Use the Minimum Angular Deviation to Determine the Wavelength

Because of the reflection of both sides of the diffraction grating,one will see a ghosting image from the telescope of the spectrometer,and cannot adjust the spectrometer properly.The angular deviation between the incent light and the diffraction light can be easily measured by the spectrometer.We first prove that the angular deviation has a minimum value,and then use it to determine the wavelength.