Cross-band apochromatic correction and applications in the lwir and swir bands

Abstract

A method for cross-band apochromatic correction in a multi-element optical system. In one example, the method includes selecting a set of design wavelengths, determining a set of optical materials that are transmissive at each design wavelength, identifying a system of linear equations that describe the multi-element optical system in terms of a normalized optical power over the set of design wavelengths, generating multiple solutions for the system of linear equations, each solution defining a set of design optical materials selected from the set of optical materials and based at least in part on calculating mean squared difference values for wavelength pair combinations of design wavelengths in the set of design wavelengths, determining a merit value for each solution using a merit function, the merit value based on minimizing the mean squared difference values, ranking the merit values of the multiple solutions, and using at least one solution of the multiple solutions to design the multi-element optical system. In some examples, at least one design wavelength is a SWIR wavelength and at least one design wavelength is a LWIR wavelength.