Metrology of Visibly Opaque, Infrared-Transparent Aerodynamic Domes, Conformal Windows, and Optical Corrector Elements

There is a growing need to fabricate visibly-opaque, infrared-transparent, high-optical-quality optics that conform to an aircraft’s outer moldline shape to reduce drag. However, fabrication of such free-form and aspheric infrared (IR) optics has proven challenging. The current fabrication bottleneck is in the speed and precision of measuring the optical figure and transmitted wavefront error for these IR optics. To meet the established technology and market gap, Bridger Photonics, Inc. proposes developing a length metrology system capable of measuring absolute length and thickness at an IR wavelength that transmits more efficiently through the critical IR materials. Bridger’s metrology system will be coupled with precise, multi-axis stages to rapidly scan and characterize free-form IR optical surfaces and thicknesses during and/or after fabrication. The system will be based on Bridger’s proprietary high-resolution coherent measurement techniques and will achieve <100 nm precision, >1 kHz update rates, and up to 100 mm measurement ranges for specular surfaces. Because of the thickness measurement capabilities, Bridger’s system will be capable of measuring the transmitted wavefront error of these IR aspheric optics.