Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


J. Korean Phy. Soc. 2008; 53(3): 1671-1674

Published online September 12, 2008

Copyright © The Korean Physical Society.

Photonic-Crystal-Type Infrared Filters for Gas Sensors

Sang Soon Oh and Choon-Gi Choi


For the purpose of carbon-dioxide (CO$_2$) sensors, we propose a photonic crystal (PhC)-type filter that has a narrow pass band at a wavelength of 4.26 $mu$m in the infrared region. Using the finite-difference time-domain (FDTD) method, we obtained the transmission spectra for various shapes and sizes of the air holes in the PhC type filters. On the basis of the numerical results, we designed and fabricated a PhC-type filter. By measuring the transmission spectra of the fabricated devices, we confirmed that the PhC-type filter could be a candidate for an element of an optical gas sensor. The behavior of the spectral response of the filter with respect to the shape and the size of the air holes was also analyzed.

Keywords: Sensor, Infrared filter, Photonic crystal