Megawatt peak-power, single-mode, mid-infrared femtosecond pulse delivery at 5–6 μm via a silica-based anti-resonant hollow core fiber
Ang Deng, Linzhen He, Yuxi Wang, Trivikramarao Gavara, Liangliang Lu, Wonkeun Chang, Hongyu Luo, Jianfeng Li, Houkun Liang
Abstract
We demonstrate the first, to our knowledge, delivery of megawatt peak power, single-mode mid-infrared (MIR) femtosecond pulses at 5–6 μm using a silica-based anti-resonant hollow core fiber (AR-HCF). Benefiting from the light confinement inside the hollow core, the AR-HCF exhibits high damage thresholds, reliable power stability, efficient spatial beam self-cleaning, and pulse shape preservation. Pumped by a homemade LGS-based two-stage optical parametric amplifier generating high-power ∼200 fs pulses, the fiber achieves a maximum delivered peak power of 4 MW at 5.1 μm and 5 MW at 6.1 μm, with peak intensities reaching 100 GW/cm 2 , despite fiber losses exceeding 2 dB/m. This flexible, meter-scale delivery system demonstrates exceptional potential for addressing the challenges of high peak power MIR laser delivery in precise, minimally invasive interventional ablation, particularly at resonant peaks such as amide-I (6.1 μm) and cholesterol esters (5.75 μm).