Plastic Diffraction-Limited Wide-Angle Air-Spaced Cooke Triplet Lens Designs for SWIR Imaging Applications: Image Quality Analysis Using Zemax®

In this study, the optical performance of plastic (acrylic-polycarbonate-acrylic, acrylic-polystyrene-acrylic, PMMA-polycarbonate-PMMA, and PMMA-polystyrene-PMMA) diffraction-limited air-spaced Cooke triplet lens designs optimized for the spectral range 0.995 to 1.01 µm are presented. Comparing the acrylic-polycarbonate-acrylic air-spaced Cooke triplet lens design with the other three plastic lens designs, the obtained results indicate that the acrylic-polycarbonate-acrylic design can achieve the best image quality performance at 50% contrast 56 cycles/mm and Strehl ratio= 0.989 for the on-axis field-of-view (FOV= 0°). Furthermore, over the temperature range 18.30 to 22.25 °C and over +12° FOV the acrylic-polycarbonate-acrylic air-spaced Cooke triplet lens design performance remained diffraction-limited (Strehl ratio < 0.8). The low cost and the light weight of plastic optical components makes them attractive for several industrial applications. As an example, plastic lenses are incorporated into cell phone cameras and LED collimation optics.