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Proceedings Paper

Hybrid cavity for photo-conductive detectors with nanoantenna arrays and distributed Bragg reflectors (Conference Presentation)
Author(s): Oleg Mitrofanov

Paper Abstract

Efficiency of photoconductive detectors is limited by the bulk optical properties of photoconductive materials. The absorption length is on the order of several hundred nanometers, which limits the device thickness. Optical absorption however in the photoconductive layer can be modified substantially by using the concept of hybrid cavity, which consists of nanoantennas and a Distributed Bragg Reflector. A hybrid cavity containing a GaAs photoconductive layer of just 50 nm can be used to absorb >75% of incident photons by trapping the light within the cavity. We will discuss an intuitive model, which describes the dependence of the optimum operation wavelength on the cavity thickness. We will also show that the nanoantenna size is a critical parameter, small variations of which lead to both wavelength shifting and reduced absorption in the cavity. This behavior suggests that impedance matching is key for achieving efficient absorption in the hybrid cavities.

Paper Details

Date Published: 29 September 2017
Proc. SPIE 10353, Optical Sensing, Imaging, and Photon Counting: Nanostructured Devices and Applications 2017, 103530J (29 September 2017); doi: 10.1117/12.2275566
Show Author Affiliations
Oleg Mitrofanov, Univ. College London (United Kingdom)

Published in SPIE Proceedings Vol. 10353:
Optical Sensing, Imaging, and Photon Counting: Nanostructured Devices and Applications 2017
Manijeh Razeghi; Oleg Mitrofanov; José Luis Pau Vizcaíno; Chee Hing Tan, Editor(s)

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