Twisted single-ring hollow-core fiber for broadband chiral detection in nanoliter volumes
Christof Helfrich,
Sonia Maniappan,
Michael Frosz,
Raju Adhikary,
Sandro Colagioia,
Nicolas Joly,
Andrea Marini,
Francesco Tani
Journal of Physics: Photonics
(2026)
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The ongoing evolution of hollow-core fibers continues to inspire the development of optofluidic platforms with enhanced sensitivity and minimal sample requirements. Here, we utilize the intrinsic advantages of anti-resonant reflection hollow-core fibers—such as low optical loss and broadband transmission—to realize a twisted single-ring hollow-core fiber (SR-HCF) tailored for polarization-sensitive chiral detection. We optimize the fiber geometry to ensure single-mode operation by strongly attenuating higher-order modes (>50 dB/m) while maintaining low loss for the fundamental mode (<0.1 dB/m) and reducing the sample volume to only ~660 nanoliters per 34 cm fiber length. By applying a constant twist along the fiber length, we minimize birefringence and ensure stable transmission of linear polarization states with polarization extinction ratios (PER) surpassing 38 dB. After injecting an aqueous solution of an optically active molecule, we measure its optical rotation (OR) at different wavelengths with millidegree-level sensitivity and remarkable robustness against misalignment. Measurements with different enantiomeric excess concentrations are in good agreement with independent liquid chromatography characterization.
accepted manuscript
Soliton self-frequency shift in hollow-core fiber for bright femtosecond radiation tunable across the short-wavelength infrared
Markus Lippl,
Martin Butryn,
Nicolas Joly,
Francesco Tani
We report a fiber-based source of femtosecond radiation that is spectrally tunable in the short-wavelength infrared region, delivering average powers at the multi-watt level. The system utilizes self-soliton frequency shifting in a hydrogen-filled hollow-core fiber, producing pulse trains at 1.1 MHz with integrated relative intensity noise below 0.3% and a polarization extinction ratio of 30 dB. This source constitutes an efficient and valid fiber-based alternative to optical parametric amplifiers for a variety of applications, including THz generation, multiphoton imaging, and high-harmonic generation.
Contact
Research Group Nicolas Joly
Professor for Photonics Friedrich-Alexander-Universität Erlangen-Nürnberg
and
Max Planck Institute for the Science of Light Staudtstr. 2 91058 Erlangen, Germany
