Electro-Optic PLZT Films for Monolithic Tunable Band-Pass Filters

Electrically tunable optical filters have been identified as a critical element in many applications, including imaging and automated target recognition applications. While large electro-optic effects can be engineered in composite structures such as multiple quantum-wells or liquid crystals, SLMs based on ceramic materials in the PbLaZrTiO3 (PLZT) family of compounds show a unique combination of high transparance and large electro-optic effects. However, integration of PLZT ceramics in interference coating designs has been a major obstacle to the commercial acceptance of this approach. ATM has pioneered the use of chemical vapor deposition (CVD) to deposit complex oxide films and we now believe that a significant opportunity exists to utilize CVD to deposit films of PLZT on glass, allowing its integration in tunable bandpass filters. In Phase I, we will deposite thick PLZT films, the electro-optic properties will be optimized and a novel multi-element tunable bandpass filter will be fabricated. In Phase II, we will scale the process to an 8" single wafer commercial CVD system used at ATM for deposition of BaSrTiO3 films for DRAMs and pyroelectric IR detectors, and the deposition process will be optimized for high uniformity PLZT layers needed for 3' diameter tunable bandpass filters.