New FIR laser lines from fully deuterated dichloromethane:completion of perpendicular/parallel emission pairs

We report 16 new far-infrared (FIR) laser emissions of CD₂ Cl₂. These lines are obtained by optically pumping the active molecule by means of a large-tunability waveguide CO₂ laser. Our tunability of 290 MHz around each CO₂ laser emission allows for the excitation of large-offset absorption transitions of CD₂Cl₂, not reachable by conventional CO₂ Lasers. While the overwhelming majority of the known FIR laser emissions of CD₂Cl₂ are polarized parallel to the polarization of the pump CO₂ line, 13 of the 16 new lines reported in this paper are polarized perpendicularly to the corresponding CO₂ pump line. The presence of both perpendicular and parallel lines is extremely important for the assignment of laser transitions