Offner and Dyson Imaging Spectrometers
Brandywine’s product cores are Offner and Dyson imaging spectrographs. We build our spectrographs to exacting image quality, distortion, throughput, and stray light specifications for use in many science applications. Our spectrographs, when mated to our image sensors, create an imaging spectrometer robust enough for the most demanding airborne and space applications.
Diffraction Grating Fabrication
Brandywine custom designs and fabricates blazed diffraction gratings specifically for its spectrometers, whether convex or concave. These diffraction gratings have very precise placement of their grooves (<25 nm) for sharp spectral performance. The surface roughness of <30 angstroms rms permits operation in the ultraviolet, while the figure of <¼-wave allows for excellent imaging. Sizes go up to 100 mm in diameter and 125 grooves/mm. Special care is taken for long-term coating performance, including UV enhanced silver and robust dielectric coatings.
VNIR and SWIR Image Sensors
Brandywine Photonics is currently building the next generation of CMOS image sensors for hyperspectral imaging. These image sensors use proprietary methods to eliminate many of the problems of CCD’s when used for science applications. This device eliminates problems such as frame transfer smear correction and fringing often found when CCD’s are used for hyperspectral imaging. The primary difference to current CMOS imagers is our higher quantum efficiency, with a projected QE of 80% from 400-900 nm, and 40% at 380-nm. Other advantages of our CMOS image sensor are an effective 40000:1 dynamic range and frame rate of >300 Hz. Please contact us for custom well depths, spectral range, and gain options. We work with our latest infrared FPA partner in developing higher performance HgCdTe, InGaAs, and Type II SLS specially for hyperspectral imaging.
When building a broadband hyperspectral system, it is critical to reduce chromatic aberrations which can cause low transmission or loss of image quality. For systems which extend below 420 nm in the blue, or cover from 380-2500 nm (VIS-SWIR), we offer all-reflective telescopes. These telescopes range from 10 mm focal lengths (50 degree FOV) to 1 meter or greater. These telescopes can either be diamond turned or CNC polished low-expansion materials, depending on the instrument’s thermal requirements. Please call about our latest CAFE ultra-compact telescopes for tightly constrained platforms.
Optical Instrument Integration
Brandywine Photonics has designed hyperspectral instruments for many hard flight environments including Unmanned Aerial Vehicles, the International Space Station, and tactical stabilized gimbals. This has required full thermal and structural analysis and testing. Each instrument for spaceflight goes through full shock and vibration at the subsystem level prior to spacecraft integration and test. Coatings are also tested at the thin film manufacturer for thermal, humidity, abrasion, and adhesion using standard Mil-Spec tests.
EXPRESSO: Exploration Processing for Real-time
Exploitation, Spectral Sensing and Ortho-rectification
Brandywine Photonics is working with the latest GP-GPU multi-core processing for high performance computing in both Earth Science and tactical applications. With our partners, we are also incorporating low-power, real-time geo/ortho-rectification processing. Whether the lab, factory floor, or in-flight, EXPRESS is the ideal workbench for turn-key or user-developed hyperspectral processing.