A simple state-of-the-art spectrometer for student labs: Cost-efficient, instructive, and widely applicable

Abstract

We present a simple, cost-effective, yet instructive spectrometer for use in undergraduate instructional laboratory courses. Deliberate design choices are made to enhance the learning experience provided by the setup, where every component is accessible to students, allowing them to fully understand the function of each individual item. The result is a state-of-the-art spectrometer, built from commercially available components, which balances pedagogical simplicity with the potential for a wide range of applications. Our setup prepares students for future spectroscopy work in research labs. Furthermore, data-taking by means of a CCD camera and the subsequent analysis teach students fundamental computational skills. Within one image, the spectrometer can cover a spectral range of 40 nm and its spectral resolution is about 0.1 nm, limited by the imaging optics. Systematic uncertainties arising from mechanical play of the grating's rotation stage limit the reproducibility of the setup to 0.65 nm. While these parameters can be improved, we decided to maintain the pedagogical and straightforward nature of the presented setup, as any increase in cost or complexity would undermine its educational benefits. Using the spectrometer in an undergraduate instructional laboratory makes possible a variety of valuable experiments, such as calibration measurements, investigation of different types of uncertainties and measurements errors, and historically important measurements (e.g., the Balmer series or solar spectrum). We are convinced that the presented spectrometer will greatly benefit the learning experience of students for many years to come.