狭缝宽度对光栅光谱仪分辨率影响的实验研究

Experimental Study on the Effect of Slit Width on the Resolution of Grating Spectrometer

分辨率是光栅光谱仪的一个重要参数,但因为光谱仪的高度集成性,围绕光谱仪的实验教学往往侧重于教学生如何使用光谱仪,使学生很难直观地建立起分辨率与狭缝宽度之间的关系。该文从WGD-8A型多功能光栅光谱仪的结构与工作原理出发,以氢氘灯的656. 11 nm和656. 28 nm双线为对象,测量了不同入射狭缝宽度和出射狭缝宽度下氢氘灯656. 11 nm和656. 28 nm双线光谱,并对测量结果做了谱线拟合,获得了不同缝宽条件下的谱线半高宽度。实验结果表明,光栅光谱仪的分辨率随着狭缝宽度的增加而降低,其灵敏度对出射狭缝的变化更为敏感,为了使光谱仪获得最为理想的分辨率,应该将入射狭缝宽度设定在0. 35 mm附近,而将出射狭缝的宽度设定在0. 18 mm以内。

Resolution is an important parameter of a grating spectrometer.However,because the spectrometer is a highly integrated instrument,the experimental teaching around the spectrometer often focuses on teaching students how to use the spectrometer;it makes it difficult for students to intuitively establish the relationship between resolution and slit width.In this paper,based on the structure and working principle of WGD-8A multifunctional grating spectrometer,the 656.11 nm and 656.28 nm double lines of hydrogen deuterium lamps were used to measure the hydrogen enthalpy lamp 656.11nm and 656.28 nm under different incident slit widths and exit slit widths.It is demonstrated that the resolution of the grating spectrometer decreases with the slit width increase,and it is more sensitive to the variation of the exit slit.In order to achieve the test resolution of spectrometer,the entrance slit width shoule be set around 0.35 mm,and the exit slit width should be set the within 0.18 mm.