Design of a Wide-Field Deflection System Using a Self-Achromatic Grism

Field-deflecting optical elements play a crucial role in various high-resolution and field-expandable optical systems. However, for widely used prism-based field-deflecting optical elements, the issue of chromatic aberration correction under wide-field conditions remains unresolved. To solve this problem, we first propose a self-achromatic double-faced grism (DFG) configuration based on a single prism and establish a parametric design model for the DFG under wide-field self-achromatic conditions. Based on this model, an optical imaging system with a field deflection range of −3.6° to +0.8° operating in the 3–5 μm wavelength band was designed. The absolute residual chromatic aberration of the DFG element is less than 0.07 across all field points, and the MTF of the imaging system exceeds 0.2@33 lp/mm for all fields. The design results demonstrate that the proposed element can effectively achieve achromatic field deflection in wide-field optical systems.