MEMS programmable spectral imaging system for remote sensing

Abstract

ITT Industries Space Systems Division and Eastman Kodak Company have developed a scalable, data-and powerefficient imaging spectrometer system with a digitally tunable optical filter capability, which enables the rapid selection of high-quality user-defined optical spectral band(s) of interest. The system utilizes a custom-designed, high-contrast diffractive MEMS device with 50 independent spectral switches at the image plane of a double-pass dispersive/dedispersive spectrometer. The custom MEMS device is based on grating electromechanical system (GEMS) display technology, which provides very high image contrast (2000:1), fast optical switching speeds (< 100 ns), and a large active area with a very high fill factor. The system enables the selection of arbitrary, narrow or wide spectral bands of interest across the visible spectrum with a sampling resolution of 5 nm, without any moving mechanical parts. The resulting optical filter quality and performance is comparable to conventional fixed-band dichroic filters used in current remote sensing systems. The brassboard systems are designed for rapid transition to space-based, electro-optical (EO) remote sensing missions that utilize large format linear TDI scanning sensors and large format area staring arrays in the visible band. This technology addresses numerous capabilities to meet future EO system requirements for rapidly selecting and utilizing a high quality imaging optical bandpass of interest. The system concept provides capability for a >20X scan rate advantage over conventional hyperspectral imagers as a result of the compatibility with TDI scanning. The image quality is comparable to current MSI and HSI systems.

A novel optical scanner for laser radar

“…Benefits of this mode include high scanning speed, however, the performances of light transmittance and field of view cannot be satisfied. The second mode is called "mechanical scanning" which includes raster scanning, galvanometer scanning, fiber scanning [4] and MEMS mirror scanning [5] . However, both of them are still in the stage of experiment and not mature enough to apply to imaging laser radar.…”