Ultra-Short-Pulse Laser Beam Delivery Through Inhibited-Coupling Hollow-Core Crystal Fiber at 2 μm

Ultra-Short-Pulse (USP) lasers emitting in the Mid-IR wavelength range have greatly matured over the last ten years, now offering high power and energy <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\geq 1 \mu \mathrm{J})$</tex> capabilities [1]. In particular, lasers operating around 2 μm have demonstrated rapid progress, exemplified by their adoption in high-precision micro-machining applications, including medical surgery and processing of specific materials [2]. However, their use in USP laser-based micro-processing still faces challenges related to cumbersome beam delivery setups and delicate focusing optics. A promising solution, successfully employed in ~1 μm laser industry, is the use of inhibited-coupling hollow-core photonic crystal fibers (IC-HCPCFs) for flexible, robust, and safe laser beam delivery [3].