Mid-IR HCPCF gas-laser emitting at 4.6 μm

Infrared laser sources emitting in the atmospheric transmission window (i.e. the wavelength range of 3-5 µm and 8-13 µm) are of interest in applications such as remote sensing, imaging and free-space communications [1]. Within this context, Inhibited Coupling Hollow Core Photonic Crystal Fibers (IC-HCPCF) [2] offer an interesting platform for gas laser sources, especially for those emitting in spectral ranges where silica-based solid core fiber lasers fail because of the large infrared (IR) absorption losses of the host materials. Indeed, the possibility of filling HCPCF with gases, and combining long gas-light interaction lengths with small modal areas opened new avenues for laser development and nonlinear optics [3]. Furthermore, IC-HCPCFs exhibit particularly weak optical overlap between the guided field and the glass cladding material (typically in the range 10-4-10-6) [4]. Consequently, material absorption losses play a minor role in the mid-IR in a few meter-long silica-based IC-HCPCF as demonstrated previously [5]. This suggests that the concept of hollow fiber gas laser (HOFGLAS), which was demonstrated in the visible with I2 [6] and at 3 µm with C2H2 pulsed [7] and CW [8], can be extended to longer wavelengths. Here, we report on an optically pumped gas-laser based on N2O-filled IC-HCPCF. The pulsed N2O HOFGLAS is pumped at 1.517 µm and emits at 4.6 µm with a photon conversion efficiency of 9% and a slope efficiency of 3%.