Hollow-core Bragg fiber and its application in trace gas sensing

A hollow-core Bragg fiber with the fundamental photonic crystal bandgap around 3000 cm-1was fabricated and injected with methane/nitrogen mixed gas with 0.5% methane concentration. A very sharp absorption line of methane gas around 3000 cm-1within the transmission band of hollow-core Bragg fiber was observed using the Fourier transform infrared spectroscopy, which demonstrated that hollow-core Bragg fiber can be used as a mid-infrared waveguide and minimized gas cell simultaneously, showing great potential in trace gas sensing.