Lock-In Focal Plane Array

The current focal plane array (FPA) technology cannot detect extremely weak image and spectral photon signals buried in strong background (Is / Ib < 10 -7 ~ 10 -4), the detection of which is, however, crucial for missile defense systems. The lock-inamplifier [1] has been playing major roles in the detection of extremely weak photon signals. However, it costs a few thousand dollars and works only for a single photon detector. The challenge is how to utilize the principles of lock-in technique to theFPA. Recently, the theory and experimental demonstration of a single pixel of the lock-in focal plane array (LI-FPA) have been published [2-4]. As a first step in the process of making LI-FPA a practical device that will play vital roles in missiledefense systems, as well as various commercial products, the objective of this proposed Phase I project is to demonstrate the feasibility of a linear LI-FPA. The technical goal is to design, fabricate, and test a 1x128 quantum well infrared photodetector(QWIP) LI-FPA, to be used as the sensor of a very long wavelength infrared (VLWIR) spectrometer. The proposed combination of the two technologies _ the lock-in and the focal plane array _ offers a unique opportunity not only for the R&D of Missile DefenseAgency and other DOD components, but also for astronomy and astrophysics, environmental monitoring, biomedicine, optical communications, and various areas involving the detection of extremely weak imaging, spectroscopic, and spectroscopic imaging signals.astronomy, soalr physics, astrophysics, environmental monitoring, optical communications, cancer early diagnosis, non-intrusive measurement of blood glucose level, and other biomedical applications.