DYNAMICS OF A BR(4(2)P(1 2)-]4(2)P(3/2)) PULSED-LASER AND A BR(P-2(1/2))-NO(NU=2-]NU=1) TRANSFER LASER-DRIVEN BY PHOTOLYSIS OF IODINE MONOBROMIDE/

An atomic bromine laser operating on the 4(2)P(1/2) - 4(2)P(3/2) trans ition at lambda = 2.71 mu m and pumped by photolysis of IBr with a fre quency-doubled Nd:YAG laser has been demonstrated. The dynamics and pe rformance of this device were characterized by observing the temporal dependence of the stimulated emission for various laser photolysis ene rgies (20-125 mJ/pulse) and IBr pressures (0.7-6.7 torr). The gain is directly proportional to the number of absorbed photolysis photons, wi th a value of 0.9 %/cm over 41 cm at an IBr pressure of Storr. The inv ersion is quenched rather slowly, with a pulse duration of greater tha n 2 mu s, after short-pulse (10 ns) excitation. The laser energy is ma ximized at 2.5 torr of iodine monobromide in a photolysis cell of 90 c m. A numerical solution to the rate equations for the laser pulse shap es provides a threshold inversion of Delta(th) = 2.9 x 10(13) atoms/cm (3). The energy efficiency of this device is limited principally by th e low quantum efficiency, poorly matched pump and cavity mode volumes, and the photolysis yield of a single isotope hyperfine component of B r(P-2(1/2)) A nitric oxide, NO(upsilon = 2 --> upsilon = 1), laser at lambda = 5.4 mu m pumped by electronic-to-vibrational energy transfer from the photolytically produced Br(P-2(1/2)) has also been demonstrat ed. The output energy and gain of this NO laser is adversely affected by rapid V-V relaxation.