Hot-band lasing in NH3

Single-photon pumping of molecular gases at low pressures does not typically yield laser transitions in the hot bands of the molecule. Thus many possible laser transitions of interest in the molecules are inaccessible under these conditions. In this letter four new hot-band laser transitions (
25.47, 25.88, 26.44, 49.04 \mu
m) in NH
3
are reported with single-photon pumping and pressures around 30 torr. Five new hot-band laser transitions (11.55, 12.16, 12.18, 26.71, 35.13) in NH
3
at lower pressures around 3 torr are also reported with two-photon pumping. Three of the lines (12.18, 35.13, 26.44) lased single pass (superfluorescent). Laser and absorption transitions have been assigned for all lines.