Low-Cost Thermo-Optic
Imaging Sensors: A Detection Principle Based on Tunable One-Dimensional
Photonic Crystals
- Publication date
- Publisher
Abstract
Infrared (IR) sensors employing optical readout represent
a promising class of devices for the development of thermographic
imagers. We demonstrate an infrared radiation detection principle
based on thermally tunable one-dimensional (1D) photonic crystals
acting as optical filters, integrated with organic and inorganic light
emitting diodes (OLEDs and LEDs, respectively). The optical filters
are composed of periodically assembled mesoporous TiO<sub>2</sub> and
SiO<sub>2</sub> layers. Due to the thermal tunability of the transmission
spectrum of the optical filter, the intensity of light passing through
the filter is modulated by temperature. The tuned spectrum lies in
the visible region and, therefore, can be directly detected by a visible-light
photodetector. The thermal response of the luminance of the OLED-photonic
crystal ensemble is 3.8 cd m<sup>โ2</sup> K<sup>โ1</sup>. Furthermore, we demonstrate that the local temperature profile
can be time and spatially resolved with a resolution of 530 by 530
pixel, thus enabling a potential application as an infrared imaging
sensor featuring low power consumption and low fabrication costs