BACKGROUND AND INTRODUCTION
  • Light Control - Optical Beam Steering
Modern defense systems utilize electro-optics devices (e.g. LIDARs) for applications such as remote sensing, target detection, etc. One of the requirements of such systems is to have directional control with high efficiency. However, the ability to scan highly directive optical systems over a large field of regard with high accuracy is a difficult mechanical problem, which is normally resolved by utilizing gimbals. An optical gimbal′s size, weight and power (SWaP) characteristics and cost make deployment unattractive for many types of platforms. The deployment of gimbal-based systems is especially difficult for small platforms such as satellites and unmanned airborne vehicles (UAVs). To reduce SWaP, mounting requirements and cost, nonmechanical steering techniques are being considered. With nonmechanical steering, the need to apply mechanical force to move massive optical elements is eliminated, reducing mechanical inaccuracies such as overshoot and ringing. Thus, nonmechanical beam control is expected to be less complicated and more reliable. These nonmechanical benefits are especially desirable if other parameters such as aperture size, efficiency and scanning range are not to be sacrificed. Other optical sensor systems have similar needs, but different attributes enter into the equation. Passive mid-wave infrared sensors for threat warning and target detection require broadband steering. For laser communications, the beam director has to provide continuous fine-angle tracking with good mechanical stability. Whereas, a laser weapon system needs to steer beams with high average power. The common link is that all of these applications require the ability to steer over a large field of regard with good precision.

  • Light Detection - Imaging Hyper-Spectral Polarimetry
Hyperspectral polarization imaging in particular is becoming increasingly important as the successful identification of particular signatures, military geological or otherwise, of- ten requires analysis full Stokes parameters over tens to hundreds of separate spectral channels with spectral resolutions on the order of 10 nm. With the advances in computer processing power and detector technology, the field of hyperspectral polarization imag- ing is continually developing. There are several types of technologies being developed for the measurement, including grating-based spectrometers, filter-based spectrometers, Fourier transform imaging spectrometers, slit spectrometers and whisk-broom scanners. Conventional technologies based on time-sequential measurements or scanning are often inappropriate in high-speed applications where the characteristics of the scene can change before the measurement series is complete (such as in the characterization of the fireball from a chemical explosion). Grating spectrometers are high-speed, particularly if multiple detectors are used, but are usually non-imaging. In addition these traditional approaches to hyperspectral polarization imaging require bulky optics with a large form factor and are expensive. For military applications in the field it is highly desirable to acquire a lower cost imaging system, which has a compact footprint and can be manufactured in high volume numbers due to reduced cost.