Coherent mid-IR supercontinuum in a hollow core fiber filled with a mixture of deuterium and nitrogen

The energy conversion into the mid-IR region (greater than 2.2 μm) was numerically studied under pumping a gas-filled revolving fiber with a hollow core with chirped picosecond pulses at the wavelength of 1.56 μm. It was shown that the combined cascade SRS process at vibrational-rotational levels in D₂ – N₂ mixture increases the degree of supercontinuum coherence and the maximum values of quantum efficiency of SRS conversion as compared to a single-cascade process in deuterium. The possibility of obtaining supercontinuum waves with 1800 nm spectral width and maximum quantum conversion efficiency of 48% in the range of partial pressures D₂ and N₂ up to 50 atm was demonstrated.