Near IR Raman laser beams generated by 1064 nm pumped Stimulated Raman Scattering (SRS) of pressurized nitrogen

Nitrogen is a nonflammable, nonexplosive and cheap Raman active gas. N2 has a vibrational Raman shift of 2330 cm-1, and there are no other Raman active media with a similar Raman shift. Therefore, the SRS of N2 plays an essential role in expanding the spectral range of Raman lasers. In this work, a pulsed 1064 nm laser was used as a pump source, and by the first and second Stokes SRS of pressurized N2, 1415 nm and 2110 nm laser beams were generated. By optimizing N2 pressure and focus configuration, the maximum pulse energies of 1415 nm and 2110 nm Raman lasers reached 109.9 mJ and 22.5 mJ, respectively. Their corresponding peak powers obtained were 20.7 MW and 4.4 MW, respectively. Comparing the thresholds of H2 (hydrogen) and N2, the first Stokes (S1) Raman gain coefficient of 1.5 MPa N2 was estimated to be about 1/9 of H2.