Tellurite anti-resonant hollow-core fibre: fabrication, mid-infrared femtosecond laser transmission, and application in tissue ablation

The absence of flexible fibers that can deliver high-intensity mid-infrared ultrafast lasers (particularly above 5 μm wavelength range) without causing pulse distortion or damage remains a major barrier for numerous applications, including laser-based minimally invasive surgery, precision material processing and gas sensing.Here, we propose a tellurite glass anti-resonant hollow-core fiber that exhibits low transmission loss in the 5-10 μm band (~2 dB/m at 5.5-6 μm or 7.5-8 μm), robust bending resilience (minimum radius of 8 cm), and improved beam quality (output M² reduced from 1.5 to 1.25).Importantly, it facilitates distortion-free delivery of ultrafast mid-infrared pulses from an optical parametric amplification system, without spectral broadening and material damage at an input peak power of 16 MW.As a proof-of-concept demonstration, the developed fiber enables wavelength-selective ablation of biological adipose tissue at 5.75 μm, for the first time, to the best of our knowledge.A record-wide operational bandwidth extending to 10 μm has been demonstrated, enabled by extended infrared edge of tellurite glass.This work confirms that tellurite anti-resonant hollow-core fibers can serve as a groundbreaking tool in ultrafast mid-infrared photonics, offering exceptional potential to tackle challenges in invasive laser surgery, gas-phase spectroscopy, and nonlinear optical studies.