The air-spaced achromatic doublet lens design provides excellent spherical and chromatic aberration correction and diffraction-limited performance. Air-spaced doublets have two more degrees of freedom than cemented doublets because the two surfaces inside the air-spaced doublet do not need to have the same curvature. This additional variable allows it to outperform cemented doublets in transmitted wavefront error, spot size, and aberration performance. The air-spaced design is highly resistant to laser damage because no adhesives are used in the manufacturing process. Air spaced design provides better anti-distortion performance The doublets are pre-mounted in an aluminum sleeve and feature tight tolerances between the lens and sleeve to minimize lens eccentricity. Each mount is individually identified, including part number, AR coating wavelength, focal length, and direction of light propagation when collimating a point source Air Spaced Achromatic Doublets are used for applica…