Chalcogenide Glass Mid-IR Optic Development

ABSTRACT: IRradiance Glass, Inc. proposes a Phase I STTR program in conjunction with the University of Central Florida to demonstrate the feasibility of the design, development, and production of high numerical aperture (NA) cylindrical lenses for use in the mid- to long-wave infrared optical region by extruding chalcogenide glasses into a micro-lens shape (~2mm wide x 2 mm high x 3 mm long) with a focal length of ~2mm and a NA of ~0.8. Feasibility of the project will be determined by the successful manufacture of several prototype lenses. Additional efforts in Phase I will investigate methods of improving laser damage threshold. A successful Phase I proof-of-concept effort will pave the way to a more comprehensive program in Phases II and III, aimed at the design and high-volume production of cylindrical lenses with robust laser damage thresholds lenses that deliver the required optical functions in a single component to be integrated in a complete QCL system.; BENEFIT: Cylindrical lenses, especially high-NA lenses, are critical for the proper collection and collimation of laser light in quantum cascade laser (QCL) systems, which are fast becoming the laser of choice for imaging and sensing applications in the infrared (3-8 micron) portion of the electromagnetic spectrum. Because of the way in which the QCL devices are fabricated, this light is not well collimated on its exit from the QCL. This beam divergence can severely degrade the optical performance system in some cases. For laser systems that operate in the visible and near-IR and suffer from the same divergence and collimation issues, cylindrical lenses made from fused silica are typically employed to correct for the beam divergence and capture all of the light exiting the laser. For mid- to long-wave IR optical systems, the cylindrical lenses available are from crystalline IR materials like ZnSe or Ge, which must be individually machined to precise optical function specifications. Extrusion of chalcogenide glass cylindrical lenses would provide a manufacturing benefit, allowing lower-cost processes and faster turn-around time for production. Creation of the proof-of-concept cylindrical lenses from IR-transparent chalcogenide glasses is the primary aim of the proposed Phase I program.