Intracavity Raman conversion for 16-μm Stokes pulse generation in para-hydrogen

Abstract.

16-μm Stokes pulses were directly generated for the first time to our knowledge by an intracavity configuration for the para-hydrogen Raman laser. We have analyzed Stokes field growth using a focused gain model and designed a pump/Stokes cavity to satisfy CO₂ pump power and pulse duration requirements for Raman oscillation. The CO₂ laser oscillation with circular polarization was realized by seeding externally circularly polarized CO₂ radiation. An output energy of 2.4 mJ was obtained with the output coupler of 0.5% transmittance, which indicated that 420 mJ of Stokes pulse energy was stored inside the cavity. This suggests that a much higher energy can be extracted by the optimization of cavity parameters.