This proposal is to develop a snap-shot polarimetric camera that operates in the short wave infrared 0.8-2.5um (SWIR). The camera will provide high frame-rate polarimetric data in a compact and lightweight module that will enable deployment in mobile and airborne platforms. Polarimetric enhanced image data has been shown to be highly beneficial for both defense and commercial applications including: target discrimination, mine detection, and remote material identification; however, compact, solid-state solutions do not currently exist in the SWIR owing to the difficulty of fabricating such a device. Our approach is to modify our existing process for fabricating visible sensors utilizing direct bonding of micro-polarizer arrays (MPA)s to a focal plane array (FPA), in order to work with an InGaAs FPA. Previous attempts at this by others found severe crosstalk and poor robustness. 4D plans to address these issues by working with FPA manufacturers to obtain suitable back-thinned FPAs, utilize our proprietary MPA precision alignment system, and knowledge of advanced packaging/bonding methods. The Phase I effort will validate the polarimetric performance between the MPA and FPA. The Phase II effort will fully develop the MPA bonding process to withstand the temperature extremes of airborne platforms and deliver a SWIR micro-polarizer camera.
Benefit: The proposed effort will develop a dynamic SWIR polarimetric imaging system that is compact, light-weight and capable of meeting the Defense Department needs for mobile and aerial platforms. Current SWIR polarimetric imaging systems are inadequate to meet the Defense Department needs. 4D currently offers micro-polarizer cameras operating in the visible spectrum where they have found widespread use in applications such as birefringence measurement, material identification, 3D shape measurement, astronomy, industrial inspection, robotic vision, haze removal, bio-tissue imaging, and polarization microscopy. By extending the response into the SWIR spectrum, no only would these existing applications benefit, but also a wealth of additional military and commercial applications (i.e. mine detection, material identification, remote sensing, target discrimination, facial recognition, Si wafer birefringence measurement) would benefit. 4D Technology would market this camera, along with our visible products, through our extensive sales and distribution channels (note this product is likely ITAR controlled).
Keywords: wiregrid polarizer, wiregrid polarizer, snap-shot imaging polarimeter, microgrid polarizer, target discrimination, micropolarizer array, polarimetry, SWIR Polarimeter, DOFP polarimeter
