Manoj K. Dasa | Searcharxiv

arXiv2026

Tunable, high pulse energy and narrow linewidth gas-filled fiber laser across near- and mid-infrared

Wavelength widely tunable infrared fiber lasers that simultaneously deliver high pulse energies with narrow linewidths are critical for applications ranging from spectroscopy to nonlinear optics, yet achieving this combination has remained a long-standing challenge. Here, we demonstrate that gas-filled anti-resonant hollow-core fiber Raman laser offers tunability across a broad spectral range from the near-infrared (~1.4 μm) to the mid-infrared (~4.6 μm), with near microjoule level high pulse energy and a narrow linewidth of few gigahertz or less. This performance arises from a unique pump laser design together with an optimized selection of gas-filled anti-resonant hollow-core fibers, opening a promising pathway toward compact, high-performance tunable infrared fiber-based sources.

physics.optics↗

arXiv2023

Synthesizing gas-filled fiber Raman lines enables access to the molecular fingerprint region

The synthesis of multiple narrow optical spectral lines, precisely and independently tuned across the near- to mid-infrared (IR) region, is a pivotal research area that enables selective and real-time detection of trace gas species within complex gas mixtures. However, existing methods for developing such light sources suffer from limited flexibility and very low pulse energy, particularly in the mid-IR domain. Here, we introduce a new concept based on the gas-filled anti-resonant hollow-core fiber (ARHCF) technology that enables the synthesis of multiple independently tunable spectral lines with high pulse energy of >1 μJ and a few nanoseconds pulse width in the near- and mid-IR region. The number and wavelengths of the generated spectral lines can be dynamically reconfigured. A proof-of-concept laser beam synthesized of two narrow spectral lines at 3.99 μm and 4.25 μm wavelengths is demonstrated and combined with photoacoustic (PA) modality for real-time SO2 and CO2 detection. The proposed concept also constitutes a promising way for IR multispectral microscopic imaging.

physics.optics↗