Design of a type of optical optical spectrometer in the UV- A spectral region

An optical spectrometer is a tool used to separate an electromagnetic radiation into its wavelength components and has a variety of applications in science and industry. In this paper, an optical spectrometer in the UV-A spectral region, which has not been investigated before, is designed. For this design, a holographic diffraction grating with a groove density of 3600 lines/mm and a number of lenses with different materials suitable for the ultraviolet region are used. To achieve high contrast and resolution, the beams of each wavelength scattered by the grating must be carefully focused on the detector screen. For this purpose, eight lenses made of silica and fused silica, which have a high transfer coefficient in the ultraviolet region, were used. Then, after the initial calculations and determining the estimated radius of curvature of the surfaces, in order to achieve the desired results, the lenses were placed at a distance of 1 mm from each other and by using appropriate operands defined in the merit function editor of Zemax software, the thickness of the surfaces and the radius of curvature of the lenses was optimized in several stages . After optimization, at the central wavelength, all points of the spot diagram were located inside the Airy disk and the resolution of approximately 30 pm was obtained, which is a very good result compared to the previous works of researchers in other areas of the electromagnetic spectrum.