Novel Photorefractive Time-Integrating Detector for the Radar Signal Processing

Using newly developed II-VI photorefractive semiconductors as time integrator and high performance TeO2 acousto optic deflectors (AODs), Brimrose proposes to develop a compact RF signal processor useful in radar signal processing. The high sensitivity of this relatively new photorefractives, in the wavelength range of 0.63ym to 1.6,um, will allow signal processing using low power near infrared laser diodes. These semiconductors have better diffraction efficiency than Bismuth Silicon Oxide (BSO), the other material frequently used to demonstrate the concept of time integration using photorefractive crystal. The use of the proposed photorefractive semiconductors will allow practical realization of the novel time-integrator allowing bias free operation. Bias free operation will increase the dynamic range and hence the sensitivity of time integrating processors. The better sensitivity of TeO2 (compared to other AODs) in the wavelength range of 0.4,um to 5.0,um will allow better sensitivity at much lower RF power and generate much less RF noise for electronics involved. The integration time of photorefractive semiconductors can be tailored from a couple of hundred milliseconds to submilliseconds by tailoring the material processing parameters. Recently we have developed some of the new II-VI photorefractives. During the Phase I program Brimrose will demonstrate a prototype compact RF signal processor using TeO2 acousto optic deflectors and II-VI photorefractive time integrator for operation using low power near infrared laser diodes. Transition metal doped CdTe and ZnTe will be used to build time integrators and their performance will be compared. The better performing integrator will be used in the proposed RF signal processor. The outcome of the proposed research will result into compact and light weight RF signal processor capable of operating at near infrared laser diode wavelengths with improved performance. Compact and light weight design will make it a portable and very useful for the field operation. It will be useful for military applications in radar processing and also for commercial applications like RF signal processing in cable TV systems.