Extending the transmission of silica hollow core fiber to 4.6 µm

In this work, an anti-resonant hollow core fiber was designed for 3-5 µm transmission and fabricated from fused silica. Due to strong core confinement, low transmission loss was measured in the MWIR, with only 0.128 dB/m loss at 4.05 µm and 0.316 dB/m loss at 4.63 µm. This pushes the usable transmission windows and the potential application areas for silica-based ARHCF beyond what has previously been shown to be possible.