A Prism-Based Optical Readout Method for MEMS Bimaterial Infrared Sensors

Adiyan U., CIVITCI F., Ferhanoğlu O., Torun H., Urey H.

IEEE PHOTONICS TECHNOLOGY LETTERS, vol.28, no.17, pp.1866-1869, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 28 Issue: 17
  • Publication Date: 2016
  • Doi Number: 10.1109/lpt.2016.2574123
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1866-1869
  • Istanbul Technical University Affiliated: Yes


This letter demonstrates a novel prism-based optical-readout, which uses a single prism to detect the incoming TM polarized wave just below the critical angle. The method is used with a 35-mu m-pixel pitch MEMS thermal sensor, whose inclination angle changes with the absorbed infrared (IR) radiation that results in an increase in the reflectivity at the prism's glass-air interface. We compared this approach with the conventional knife-edge method. Noise equivalent temperature difference for a single sensor was measured as 200 mK for knife-edge method, and 154 mK for the proposed critical angle approach. Our approach shows a significant improvement for the sensitivity of the IR sensor. Both methods utilize an AC-coupled readout method for a single MEMS pixel using a photodetector, which responds only to changes in the scene. This method can be scaled to achieve smart pixel cameras for read sensor arrays with low-noise and high-dynamic range.