Abstract
Many applications -like spectroscopy- require spectral filtering, commonly achieved using Fabry-Pérot stacks. These can be designed to fulfill varying requirements (central wavelength, bandwidth and rejection). However, practical fabrication of the stack imposes some limitations. Indeed, reducing the bandwidth requires an increasing number of layers and ultra-narrowband filters are hard to fabricate. Similarly, extending to long wavelengths necessitates thicker layers that are not easily grown or deposited. Ultra-narrow-band filters in the mid-infrared are thus particularly difficult to obtain using this approach. In that particular aspect, resonant grating filters are an extremely interesting alternative. Especially for narrow band free-space filtering in the MIR region, as required for gas sensing (CH4, CO,…). A resonant grating filter is a sub-wavelength periodically structured planar waveguide that reflects and transmits light specularly, with the same reflection and transmission coefficient than that of the unstructured waveguide, except at resonance, where the structure exhibit one pole (100% reflection) and one zero (0% reflection)[1]. These are due to the diffraction grating that couple the incident beam, for a given wavelength and incident angle, and thus excite a mode in the structure (Figure 1 left). By reciprocity, this grating will also uncouple the mode to emit light.
© 2011 Optical Society of America
PDF ArticleMore Like This
Sylvain Augé, Sergei Gluchko, Sylvain Pelloquin, Anne-Laure Fehrembach, Thomas Antoni, Antoine Monmayrant, Evgeni Popov, and Olivier Gauthier-Lafaye
CK_11_1 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2017
C. Chevallier, N. Fressengeas, F. Genty, J. Jacquet, Y. Laaroussi, G. Almuneau, D. Sanchez, L. Cerutti, and T. Taliercio
FWS5 Frontiers in Optics (FiO) 2011
Wolfgang Schweinberger, Daniel Gerz, Thomas Butler, Thomas Siefke, Martin Heusinger, Tatiana Amotchkina, Vladimir Pervak, Uwe Zeitner, and Ioachim Pupeza
JW2A.69 CLEO: Applications and Technology (CLEO:A&T) 2019