BARRINGTON, N.J., Feb. 25, 2011 — TechSpec silicon planoconvex (PCX) lenses manufactured by Edmund Optics Inc. are suitable for use in weight-sensitive infrared applications from 3 to 5 µm, for near-infrared imaging and infrared spectroscopy, with density less than half that of germanium or zinc selenide. The lenses feature precision polished surfaces with a positive focal length and with one flat and one convex surface. They are designed for orientation with the plano (flat) surface facing toward the desired focal plane. They are available in focal lengths from 25 to 250 mm and are offered uncoated. They also may be coated with a wide range of the company’s custom infrared coatings. The lenses are manufactured of low-cost, low-density silicon and are suitable for use in the 1.2- to 7-µm wavelength range. Silicon features a density of 2.329 g/cm3 and an index of refraction of 3.422. Another feature of silicon is that it will react with halogens and dilute alkalis but is inert to most acids. It features a Knoop hardness rating of 1150, which is harder and less brittle than germanium, for robustness and durability. Available in 25-mm diameters, the lenses can be used in a variety of collimation and focusing applications using monochromatic illumination. They are in stock and available for immediate delivery.