NIR Microlens Comparison

OSA Optics Express publishes ISAE-SUPAERO and CNRS joint paper "Integration of nanostructured planar diffractive lenses dedicated to near infrared detection for CMOS image sensors" by Thomas Lopez, Sébastien Massenot, Magali Estribeau, Pierre Magnan, Fabrice Pardo, and Jean-Luc Pelouard. The paper compares pixel Plasmonic Lens, Phase-Fresnel Lens, and metallic diffractive lens technologies for a monochromatic application at 1.064µm:

"The first is a Plasmonic Lens, based on the phase delay through nanoslits, which has been found to be hardly compatible with current CMOS technology and exhibits a notable metallic absorption. The second is a dielectric Phase-Fresnel Lens integrated at the top of a pixel, it exhibits an Optical Efficiency (OE) improved by a few percent and an angle of view of 50°. The third one is a metallic diffractive lens integrated inside a pixel, which shows a better OE and an angle of view of 24°."