Ultraviolet relay optical system with wide spectrum based on diffractive elements

Ultraviolet (UV) image intensifiers are widely used in corona detection, strategic national defense, scientific research and other fields. However, due to the lack of available materials for the UV optical lens and the difficulty of chromatic aberration correction, it is difficult to meet the needs of wide spectrum applications. The applicability of single-layer diffractive optical element (DOE) and double-layer diffractive optical element in broadband UV optical system was analyzed. A set of UV optical system with the wide spectrum and the high resolution were designed respectively. The working wavelength range of the single-layer diffractive UV optical system is 230 nm~280 nm, and the modulation transfer function (MTF) value at the cut-off frequency of 60 lp·mm⁻¹ is better than 0.47. The working wavelength range of the double-layer diffractive UV optical system is 200 nm~400 nm, and the MTF value at the cut-off frequency of 60 lp·mm⁻¹ is better than 0.49. The design results show that the DOE can effectively correct the chromatic aberration of the UV spectrum. Compared with the existing wide spectrum UV system, the designed optical systems are relay imaging systems with wider UV spectral range and higher imaging resolution.