New designs and applications of corrugated QWIPs

Corrugated QWIPs are sensitive to only one polarization of light. We used two C-QWIPs with their corrugations oriented in orthogonal directions for polarization-sensitive detection. By measuring the photocurrent ratio from these two detectors, the polarization-state of the radiation rather than its intensity can be sensed; the detection is useful in scenes with extremely small or large intensity contrast. Using C-QWIPs for detector characterization, we obtained the intensity decay function of light propagating nearly parallel to the layers, with which the absorption coefficient can be measured. New C-QWIPs have been designed to improve the detector performance. In one approach, additional vertical trenches are etched into C-QWIP structures. In another approach, the entire corrugated area is covered with a conformal dielectric and a metal. Both approaches prove effective.