Transmission behaviors of single mode hollow metallic waveguides dedicated to mid-infrared nulling interferometry

Abstract

This paper reports the characterization of hollow metallic waveguides (HMW) to be used as single-mode wavefront filters for nulling interferometry in the 6-20µm range. The measurements presented here were performed using both single-mode and multimode conductive waveguides at 10.6µm. 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's 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. 1601-1610 (2000). 15. L. Labadie, E. Le Coarer, R. Maurand, P. Labeye, P. Kern, B. Arezki, and J.-E. Broquin, "Mid-infrared laser light nulling experiment using single-mode conductive waveguides," A&A 471, 355-360 (2007).

Mid-infrared laser light nulling experiment using single-mode conductive waveguides

“…Theoretical studies on the filtering length of conductive waveguides for infrared radiation suggest that the waveguides could be even shorter to compensate for high propagation losses (Abel-Tibérini et al 2007) without altering the filtering capabilities.…”

“…The technique is based on starlight cancellation by means of destructive interference in the midinfrared, i.e. from 5 µm to 20 µm (Bracewell 1978;Léger et al 1996;Angel & Woolf 1997). This spectral band presents the advantage of a lower star-companion contrast by three orders of magnitude with respect to the visible domain (Bracewell & McPhie 1979).…”

Ultrasensitive terahertz/infrared waveguide modulators based on multilayer graphene metamaterials

“…). The level of ohmic losses in single‐mode micro‐sized metallic waveguides at 30 Thz is around 0.015 − 0.016 dB/μm for cores with linear sizes of several micrometres . To ensure low losses, hollow THz waveguides typically have a dielectric lining .…”

Mid-infrared guided optics: a perspective for astronomical instruments

“…This method is also named "cut-back method". This method gives good results, but requires then a dedicated set of waveguides planned in the manufacturing phase [49] Measurement campaigns on the different type of waveguides presented in Sect. perimental measurements at longer wavelengths for chalcogenide fibers have led to increased values up to 40 dB/m between 12 and 13 µm, and 150 to 300 dB/m between 16 to 20 µm [50].…”