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Modeling and Performance of Pyroelectric Detector Lithium Niobate under Ringing Signal Suppression

  • Author(s): Peng, Gary Meng Kiang
  • Advisor(s): Stafsudd, Oscar
  • et al.
Abstract

Lithium Niobate (LiNbO3) is an excellent photo sensor that can be used in medical imaging, weapons guidance systems, radiation detection, and many other light sensitive applications. It can operate at its natural state without requiring extensive heating or cooling modifications. However, when LiNbO3 is used as a photo detector, its functionality becomes limited because it produces many signal oscillations. These oscillations make the real signal and the background noise indistinguishable. This phenomenon is known as the "Ringing Effect." To address this issue, Lithium Niobate is cut at a crystal orientation that reduces signal oscillations. In this paper I present: the experimental set up, device performance, along with detailed derivations of the circuit model, temperature, and charge models that are specific to LiNbO3.

Ringing suppressions were tested under three sets of variables: 1) various sample thicknesses; 2) different irradiation angles; 3) the addition of a black absorbing layer on the illuminated surface. The resulting signal response time under the previously mentioned circumstances were measured and compared.

Our conclusion is that ringing effect can be reduced by a correct crystal cut. The attained signal response time under ringing suppression was in the sub-nanosecond range. The added black coating layer on the illuminated surface did not always give faster performance. It was observed that a decrease in the sample thickness could reduce response time.

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