12 research outputs found
Transmission behaviors of single mode hollow metallic waveguides dedicated to mid-infrared nulling interferometry
This paper reports the characterization of hollow metallic waveguides (HMW)
to be used as single-mode wavefront filters for nulling interferometry in the
6-20 microns range. The measurements presented here were performed using both
single-mode and multimode conductive waveguides at 10.6 microns. We found
propagation losses of about 16dB/mm, which are mainly due to the theoretical
skin effect absorption in addition to the roughness of the waveguide metallic
walls. The input and output coupling efficiency of our samples has been
improved by adding tapers to minimize the impedance mismatch. A proper
distinction between propagation losses and coupling losses is presented.
Despite their elevate propagation losses, HMW show excellent spatial filtering
capabilities in a spectral range where photonics technologies are only
emerging.Comment: This paper was published in Optics Express and can be found at
http://www.opticsinfobase.org/abstract.cfm?URI=oe-15-26-1800
Spectrophotometric bench dedicated to the characterization of micro-patterned optical coatings
International audienc
Banc de mesure de la transmission spectrale de filtres interférentiels à forte structuration spatiale
National audienc
400-1000 nm all-dielectric linear variable filters for ultra compact spectrometers
International audienc
High accuracy measurement of the residual air gap thickness of thin-film and solid-spaced filters assembled by optical contacting
International audienceOptical contacting is a powerful tool for assembling solid-spaced filters in order to form a wavelength division multiplexing (WDM) multiple-cavity filter. In this article, we propose a method able to characterize the optical quality of such assembling with a high accuracy. We use localized spectral transmittance measurements to map the thickness of the residual air gap existing at the adhesion interface with a few nanometers precision. Tests on thick (2 mm) and thin (100 ÎĽm) substrates coated by Dual Ion Beam Sputtering are performed. Thus, we show that our 25 mm-diameter samples are strictly contacted over more than 80% of their surface, with no detectable residual air gap
Intégration des filtres optiques interférentiels au plus près des détecteurs plans focaux
National audienc