New far-infrared laser lines in N15H3

Several isotopes of NH
3
have been studied as laser candidates, including ND
2
H, NH
2
D, ND
3
, and N
¹⁵
H
3
. Lasing was observed in N
¹⁵
H
3
at 15.08 and 15.91 μ. Tentative assignments of transitions to the
2\nu_{2} \rightarrow \nu_{2}
vibrational levels have been made. Enhanced energy output was observed in N
¹⁴
H
3
with the addition of helium.