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Updated: Sep 3, 2026

In-situ Tapering of Chalcogenide Fiber for Mid-infrared Supercontinuum Generation
Published on: May 27, 2013
Helium-enhanced spectral broadening in CO2-filled hollow-core fiber
Abstract:
We demonstrate enhanced spectral broadening of femtosecond pulses (330 fs, 1030 nm, 5-200 kHz) in a hollow-core fiber (HCF) using CO2/helium gas mixtures. While increasing pure CO2 pressure broadens the spectrum and induces a Raman redshift, it causes substantial optical loss. Introducing a helium buffer enables strong broadening at reduced CO2 pressures, significantly decreasing loss. Propagating pulses through a 1-m-long, 300-μm-core HCF, we show that helium enhances spectral width, extends the Raman shift, and improves transmitted power by facilitating spatial cooling. This binary molecular/noble gas approach provides a robust, low-loss route for spectral engineering in HCFs.
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