Low-cost moderate-resolution spectrometer without grating

Most spectrometers used for field measurements are based on a diffraction grating to disperse light. Not only are they expensive, but they have some design setbacks as well. A prism does not have the resolving power of a grating, however, enhanced dispersion can be obtained using only a prism and a convex hyperbolic mirror. In this study, we present the design of a prism-based spectrometer, and an analytical model that represents its function. Simulations based on this model and experimental results show that a spectral sampling of 0.1 nm can be accomplished with this design. In addition to dispersion, we address the issue of linearity in the spectral domain and we present simulated and experimental results. Our design should to be cheaper, more lightweight and more light-efficient than typical grating spectrometers.