H. D. Morrison, B. K. Garside, and J. Reid, “Dynamics of the optically pumped midinfrared NH3laser at high pump power—Part I: inversion gain,” IEEE J. Quantum Electron. QE-20, 1051–1060 (1984).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “Line-tunable oscillation of a cw NH3laser from 10.7 to 13.3 μm,” Appl. Phys. Lett. 44, 380–382 (1984).

[Crossref]

H. D. Morrison, J. Reid, and B. K. Garside, “16–21-μm linetunable NH3laser produced by two-step optical pumping,” Appl. Phys. Lett. 45, 321–323 (1984).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

P. Minguzzi, M. Tonelli, A. Carrozzi, and A. Di Lieto, “Optoacoustic laser Stark spectroscopy in the ν2 band of 14NH3,” J. Mol. Spectrosc. 96, 294–305 (1982).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “12 μm Raman lasers in NH3pumped by low-power CO2laser pulses,” IEEE J. Quantum Electron. QE-18, 182–186 (1982).

[Crossref]

N. Yamabayashi, K. Fukai, K. Miyazaki, and K. Fujisawa, “Resonant pumping far-infrared NH3laser,” Appl. Phys. B 26, 33–36 (1981).

[Crossref]

H. Tashiro, K. Suzuki, K. Toyoda, and S. Namba, “Wide-range line-tunable oscillation of an optically pumped NH3laser,” Appl. Phys. 21, 237–240 (1980).

[Crossref]

B. I. Vasil’ev, A. Z. Grasyuk, A. P. Dyad’kin, A. N. Sukhanov, and A. B. Yastrebkov, “High-power efficient optically pumped NH3laser, tunable over the range 770–890 cm−1,” Sov. J. Quantum Electron. 10, 64–68 (1980).

[Crossref]

F. E. Hovis and C. B. Moore, “Temperature dependence of vibrational energy transfer in NH3and H218O,” J. Chem.Phys. 72, 2397–2402 (1980).

[Crossref]

N. Yamabayashi, T. Yoshida, K. Miyazaki, and K. Fujisawa, “Infrared multi-line NH3laser and its application for pumping an InSb laser,” Opt. Commun. 30, 245–248 (1979).

[Crossref]

S. M. Fry, “Optically pumped multiline NH3laser,” Opt. Commun. 19, 320–324 (1976).

[Crossref]

V. S. Letokhov and A. A. Makarov, “Kinetics of excitation of molecular vibrations by infrared laser radiation,” Sov. Phys. JETP 36, 1091–1096 (1973).

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

To calculate temperature changes, we used heat capacities at constant volume of 29.0 J/(mol K) and 20.7 J/(mol K) for NH3and N2, respectively, derived from W. Braker and A. L. Mossman, Matheson Gas Data Book, 5th ed.(Matheson Gas Products, East Rutherford, N.J., 1971).

P. Minguzzi, M. Tonelli, A. Carrozzi, and A. Di Lieto, “Optoacoustic laser Stark spectroscopy in the ν2 band of 14NH3,” J. Mol. Spectrosc. 96, 294–305 (1982).

[Crossref]

P. Minguzzi, M. Tonelli, A. Carrozzi, and A. Di Lieto, “Optoacoustic laser Stark spectroscopy in the ν2 band of 14NH3,” J. Mol. Spectrosc. 96, 294–305 (1982).

[Crossref]

B. I. Vasil’ev, A. Z. Grasyuk, A. P. Dyad’kin, A. N. Sukhanov, and A. B. Yastrebkov, “High-power efficient optically pumped NH3laser, tunable over the range 770–890 cm−1,” Sov. J. Quantum Electron. 10, 64–68 (1980).

[Crossref]

S. M. Fry, “Optically pumped multiline NH3laser,” Opt. Commun. 19, 320–324 (1976).

[Crossref]

N. Yamabayashi, K. Fukai, K. Miyazaki, and K. Fujisawa, “Resonant pumping far-infrared NH3laser,” Appl. Phys. B 26, 33–36 (1981).

[Crossref]

N. Yamabayashi, T. Yoshida, K. Miyazaki, and K. Fujisawa, “Infrared multi-line NH3laser and its application for pumping an InSb laser,” Opt. Commun. 30, 245–248 (1979).

[Crossref]

N. Yamabayashi, K. Fukai, K. Miyazaki, and K. Fujisawa, “Resonant pumping far-infrared NH3laser,” Appl. Phys. B 26, 33–36 (1981).

[Crossref]

H. D. Morrison, B. K. Garside, and J. Reid, “Dynamics of the optically pumped midinfrared NH3laser at high pump power—Part I: inversion gain,” IEEE J. Quantum Electron. QE-20, 1051–1060 (1984).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “Line-tunable oscillation of a cw NH3laser from 10.7 to 13.3 μm,” Appl. Phys. Lett. 44, 380–382 (1984).

[Crossref]

H. D. Morrison, J. Reid, and B. K. Garside, “16–21-μm linetunable NH3laser produced by two-step optical pumping,” Appl. Phys. Lett. 45, 321–323 (1984).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “12 μm Raman lasers in NH3pumped by low-power CO2laser pulses,” IEEE J. Quantum Electron. QE-18, 182–186 (1982).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

B. I. Vasil’ev, A. Z. Grasyuk, A. P. Dyad’kin, A. N. Sukhanov, and A. B. Yastrebkov, “High-power efficient optically pumped NH3laser, tunable over the range 770–890 cm−1,” Sov. J. Quantum Electron. 10, 64–68 (1980).

[Crossref]

F. E. Hovis and C. B. Moore, “Temperature dependence of vibrational energy transfer in NH3and H218O,” J. Chem.Phys. 72, 2397–2402 (1980).

[Crossref]

V. S. Letokhov and A. A. Makarov, “Kinetics of excitation of molecular vibrations by infrared laser radiation,” Sov. Phys. JETP 36, 1091–1096 (1973).

V. S. Letokhov and A. A. Makarov, “Kinetics of excitation of molecular vibrations by infrared laser radiation,” Sov. Phys. JETP 36, 1091–1096 (1973).

P. Minguzzi, M. Tonelli, A. Carrozzi, and A. Di Lieto, “Optoacoustic laser Stark spectroscopy in the ν2 band of 14NH3,” J. Mol. Spectrosc. 96, 294–305 (1982).

[Crossref]

N. Yamabayashi, K. Fukai, K. Miyazaki, and K. Fujisawa, “Resonant pumping far-infrared NH3laser,” Appl. Phys. B 26, 33–36 (1981).

[Crossref]

N. Yamabayashi, T. Yoshida, K. Miyazaki, and K. Fujisawa, “Infrared multi-line NH3laser and its application for pumping an InSb laser,” Opt. Commun. 30, 245–248 (1979).

[Crossref]

F. E. Hovis and C. B. Moore, “Temperature dependence of vibrational energy transfer in NH3and H218O,” J. Chem.Phys. 72, 2397–2402 (1980).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

H. D. Morrison, B. K. Garside, and J. Reid, “Dynamics of the optically pumped midinfrared NH3laser at high pump power—Part I: inversion gain,” IEEE J. Quantum Electron. QE-20, 1051–1060 (1984).

[Crossref]

H. D. Morrison, J. Reid, and B. K. Garside, “16–21-μm linetunable NH3laser produced by two-step optical pumping,” Appl. Phys. Lett. 45, 321–323 (1984).

[Crossref]

To calculate temperature changes, we used heat capacities at constant volume of 29.0 J/(mol K) and 20.7 J/(mol K) for NH3and N2, respectively, derived from W. Braker and A. L. Mossman, Matheson Gas Data Book, 5th ed.(Matheson Gas Products, East Rutherford, N.J., 1971).

H. Tashiro, K. Suzuki, K. Toyoda, and S. Namba, “Wide-range line-tunable oscillation of an optically pumped NH3laser,” Appl. Phys. 21, 237–240 (1980).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “Line-tunable oscillation of a cw NH3laser from 10.7 to 13.3 μm,” Appl. Phys. Lett. 44, 380–382 (1984).

[Crossref]

H. D. Morrison, B. K. Garside, and J. Reid, “Dynamics of the optically pumped midinfrared NH3laser at high pump power—Part I: inversion gain,” IEEE J. Quantum Electron. QE-20, 1051–1060 (1984).

[Crossref]

H. D. Morrison, J. Reid, and B. K. Garside, “16–21-μm linetunable NH3laser produced by two-step optical pumping,” Appl. Phys. Lett. 45, 321–323 (1984).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “12 μm Raman lasers in NH3pumped by low-power CO2laser pulses,” IEEE J. Quantum Electron. QE-18, 182–186 (1982).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “Line-tunable oscillation of a cw NH3laser from 10.7 to 13.3 μm,” Appl. Phys. Lett. 44, 380–382 (1984).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “12 μm Raman lasers in NH3pumped by low-power CO2laser pulses,” IEEE J. Quantum Electron. QE-18, 182–186 (1982).

[Crossref]

C. H. Townes and A. L. Schawlow, Microwave Spectroscopy (Dover, New York, 1975).

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

B. I. Vasil’ev, A. Z. Grasyuk, A. P. Dyad’kin, A. N. Sukhanov, and A. B. Yastrebkov, “High-power efficient optically pumped NH3laser, tunable over the range 770–890 cm−1,” Sov. J. Quantum Electron. 10, 64–68 (1980).

[Crossref]

H. Tashiro, K. Suzuki, K. Toyoda, and S. Namba, “Wide-range line-tunable oscillation of an optically pumped NH3laser,” Appl. Phys. 21, 237–240 (1980).

[Crossref]

H. Tashiro, K. Suzuki, K. Toyoda, and S. Namba, “Wide-range line-tunable oscillation of an optically pumped NH3laser,” Appl. Phys. 21, 237–240 (1980).

[Crossref]

P. Minguzzi, M. Tonelli, A. Carrozzi, and A. Di Lieto, “Optoacoustic laser Stark spectroscopy in the ν2 band of 14NH3,” J. Mol. Spectrosc. 96, 294–305 (1982).

[Crossref]

C. H. Townes and A. L. Schawlow, Microwave Spectroscopy (Dover, New York, 1975).

H. Tashiro, K. Suzuki, K. Toyoda, and S. Namba, “Wide-range line-tunable oscillation of an optically pumped NH3laser,” Appl. Phys. 21, 237–240 (1980).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

B. I. Vasil’ev, A. Z. Grasyuk, A. P. Dyad’kin, A. N. Sukhanov, and A. B. Yastrebkov, “High-power efficient optically pumped NH3laser, tunable over the range 770–890 cm−1,” Sov. J. Quantum Electron. 10, 64–68 (1980).

[Crossref]

N. Yamabayashi, K. Fukai, K. Miyazaki, and K. Fujisawa, “Resonant pumping far-infrared NH3laser,” Appl. Phys. B 26, 33–36 (1981).

[Crossref]

N. Yamabayashi, T. Yoshida, K. Miyazaki, and K. Fujisawa, “Infrared multi-line NH3laser and its application for pumping an InSb laser,” Opt. Commun. 30, 245–248 (1979).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

B. I. Vasil’ev, A. Z. Grasyuk, A. P. Dyad’kin, A. N. Sukhanov, and A. B. Yastrebkov, “High-power efficient optically pumped NH3laser, tunable over the range 770–890 cm−1,” Sov. J. Quantum Electron. 10, 64–68 (1980).

[Crossref]

N. Yamabayashi, T. Yoshida, K. Miyazaki, and K. Fujisawa, “Infrared multi-line NH3laser and its application for pumping an InSb laser,” Opt. Commun. 30, 245–248 (1979).

[Crossref]

H. Tashiro, K. Suzuki, K. Toyoda, and S. Namba, “Wide-range line-tunable oscillation of an optically pumped NH3laser,” Appl. Phys. 21, 237–240 (1980).

[Crossref]

N. Yamabayashi, K. Fukai, K. Miyazaki, and K. Fujisawa, “Resonant pumping far-infrared NH3laser,” Appl. Phys. B 26, 33–36 (1981).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “Line-tunable oscillation of a cw NH3laser from 10.7 to 13.3 μm,” Appl. Phys. Lett. 44, 380–382 (1984).

[Crossref]

H. D. Morrison, J. Reid, and B. K. Garside, “16–21-μm linetunable NH3laser produced by two-step optical pumping,” Appl. Phys. Lett. 45, 321–323 (1984).

[Crossref]

H. D. Morrison, B. K. Garside, and J. Reid, “Dynamics of the optically pumped midinfrared NH3laser at high pump power—Part I: inversion gain,” IEEE J. Quantum Electron. QE-20, 1051–1060 (1984).

[Crossref]

C. Rolland, J. Reid, and B. K. Garside, “12 μm Raman lasers in NH3pumped by low-power CO2laser pulses,” IEEE J. Quantum Electron. QE-18, 182–186 (1982).

[Crossref]

F. E. Hovis and C. B. Moore, “Temperature dependence of vibrational energy transfer in NH3and H218O,” J. Chem.Phys. 72, 2397–2402 (1980).

[Crossref]

P. Minguzzi, M. Tonelli, A. Carrozzi, and A. Di Lieto, “Optoacoustic laser Stark spectroscopy in the ν2 band of 14NH3,” J. Mol. Spectrosc. 96, 294–305 (1982).

[Crossref]

S. M. Fry, “Optically pumped multiline NH3laser,” Opt. Commun. 19, 320–324 (1976).

[Crossref]

N. Yamabayashi, T. Yoshida, K. Miyazaki, and K. Fujisawa, “Infrared multi-line NH3laser and its application for pumping an InSb laser,” Opt. Commun. 30, 245–248 (1979).

[Crossref]

V. G. Averin, M. Akhrarov, G. S. Baronov, B. I. Vasil’ev, A. Z. Grasyuk, M. G. Morozov, E. P. Skvortsova, and A. B. Yastrebkov, “Dissociation of UF6molecules involving excitation of combination modes by NH3–N2laser radiation,” Sov. J. Quantum Electron. 13, 189–194 (1983).

[Crossref]

B. I. Vasil’ev, A. Z. Grasyuk, A. P. Dyad’kin, A. N. Sukhanov, and A. B. Yastrebkov, “High-power efficient optically pumped NH3laser, tunable over the range 770–890 cm−1,” Sov. J. Quantum Electron. 10, 64–68 (1980).

[Crossref]

V. S. Letokhov and A. A. Makarov, “Kinetics of excitation of molecular vibrations by infrared laser radiation,” Sov. Phys. JETP 36, 1091–1096 (1973).

For most of the pumping conditions that we examine, the relaxation rates are fast enough that the vibrational populations follow the variations in pump intensity after the peak of the pulse. As the pump absorption is saturated at intensities well below 950 kW/cm2 (see Section 4.C), changes in the intensity by as much as a factor of 2 have negligible effect on the gain calculation.

To calculate temperature changes, we used heat capacities at constant volume of 29.0 J/(mol K) and 20.7 J/(mol K) for NH3and N2, respectively, derived from W. Braker and A. L. Mossman, Matheson Gas Data Book, 5th ed.(Matheson Gas Products, East Rutherford, N.J., 1971).

Linear interpolation between rate coefficients provided by Hovis and Moore17was employed to evaluate the V–T rates up to 398 K, the maximum temperature reported. For temperatures greater than 398 K the V–T rates were maintained equal to the values for 398 K.

C. H. Townes and A. L. Schawlow, Microwave Spectroscopy (Dover, New York, 1975).

This is equivalent to setting the parameter t of Ref. 6 equal to its maximum value of t= 1.0.

Ortho-NH3consists of molecules with rotational quantum number K = 3n, and para-NH3consist of molecules with K = 3n±1.