Low-loss tellurite anti-resonant hollow-core fiber for 2–10 μm laser delivery

We report a low-loss tellurite anti-resonant hollow-core fiber (AR-HCF) for mid-infrared laser delivery across the 2-10 μm spectral range. By optimizing the fabrication process with precise pressure control, we achieve a record-low loss of 0.3 ± 0.02 dB/m at 4.65 μm while extending transmission capability up to 10 μm, significantly outperforming silica-based AR-HCFs. The fiber exhibits exceptional power handling capability, enabling uncooled operation at 30.3 W input (1.976 μm) and 14.3 W output through a 1-meter-long fiber, and maintains stable transmission for 40 minutes (0.77% RMS fluctuation). Beam quality remains near-diffraction-limited (M² < 1.2) across power levels, confirming robust single-mode performance. Additionally, approaching watt-level transmission at 4.65 μm (61% efficiency, 0.5-meter-long fiber) highlights its mid-infrared potential. This work establishes tellurite AR-HCFs as a transformative platform for broadband mid-infrared applications, combining thermal stability, low loss, and exceptional beam quality.