Design of a nonlinearity-corrected spectrometer based on curved prism

As a special type of dispersion element, a curved prism features high efficiency and no overlapping spectra, but suffers from nonlinear dispersion caused by the characteristics of the material. This paper proposes a design method for a nonlinearity-corrected spectrometer combining glass and optical plastic. We theoretically analyze the dispersion characteristics of the curved prism by using the method of equivalent triangular prism based on the theory of vector solving. This analysis is used to calculate the initial parameters for pairs of prisms. The method features simplified calculation, and the design achieves the benefits of compactness and light weight. The simulation results show that the spectral resolution varies from 4.9 to 7.1 nm in a wide spectrum (400–1000 nm); the nonlinearity ratio is nearly 1:2, making the dispersion across the wide spectrum nearly homogenized; and the spectral keystones and smiles of the system are less than 0.15 pixels. Under the same specifications, the weight of a combination of glass and optical plastic apparently decreases compared to that of the design with glass alone. The results demonstrate that the nonlinearity of the prism spectrometer is corrected to a large extent and merits such as light weight, compactness, and high throughout are achieved. This method can be applied to the field of biological detection, such as in a microscopic spectrometer.