Low Cost SWIR Hyperspectral Imaging System
Hyperspectral imaging allows the identification of features and data in a scene that is not evident in a monochromatic image. The shortwave infrared (SWIR) wavelength range, from 900 to 1700 nm, can be used for applications such as explosives detection, agricultural crop health monitoring, and humanitarian aid and logistics. Humanitarian applications include the detection of people in storm raged areas, determination of safe landing locations, visual detection of gas and oil leaks, and detection of people carrying explosives in uncontrolled areas. Current hyperspectral systems are expensive due to their use of large format arrays and complicated optical components requiring pixel level alignment. In this program, the micro-lens array (MLA) will be fabricated directly into the detector array to eliminate the expensive and timely alignment steps when the two components are fabricated independently and attached together. This novel approach will improve alignment accuracy, improve the structural integrity for improved shock and vibration resistance, and is conducive for wafer scale techniques for large volume production. To enhance the number of material types that can be identified and detected, the team will develop SWIR imagers with extended wavelength detection capabilities from 900 to 2500 nm. The state of the art imager with integrated MLA will be integrated into camera that weighs less than 800g, consumes less than 10 W, and measures less than 1200 cm3. The demonstration camera unit will provide the user with a capability to detect several chemicals in real-time using a color coding scheme in the output video imagery making interpretation fast and simple for the operator. In Phase 1 we will demonstrate that InP microlenses can be formed and we will model the lens structure needed in the Phase 2 effort. We will also model an extended wavelength SWIR imager manufactured by a Type 2 Strained layer superlattice structure grown on InP. The model will indicate the potential quantum efficiency and noise characteristics of the new detector structure.