He Rui optics' achromatic doublets are optimized to provide a nearly constant focal length across a broad bandwidth. This is accomplished by utilizing a multi-element design to minimize the chromatic aberration of the lens. Dispersion in the first (positive) element of the doublet is corrected by the second (negative) element, resulting in better broadband performance than spherical singlets or aspheric lenses.
He Rui optics'spherical doublet lenses have been corrected for various aberrations, including spherical aberration, chromatic aberration, and coma. One way of displaying the theoretical level of correction is through plots of wavefront error and ray traces to determine spot size.