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Updated: May 17, 2026

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
Published on: March 22, 2019
Mid-infrared nulling interferometry beam combiners using asymmetric directional couplers
Abstract:
We demonstrate reproducible asymmetric directional couplers in gallium-lanthanum-sulfide (GLS) chalcogenide glass, using ultrafast laser inscription (ULI). This enables on-chip high-contrast nulling interferometry in the mid-infrared, specifically aimed at detecting giant exoplanets in the astronomical L' band (3.5-4.0 μm). By leveraging a classical two-telescope integrated optics beam combination scheme and conducting characterization in a laboratory environment, we demonstrate an extinction ratio of ∼10-2 across 3.65-3.85 μm.
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