Lasing without inversion explained

Lasing without inversion (LWI),^[1] or lasing without population inversion, is a technique used for light amplification by stimulated emission without the requirement of population inversion.^[2] A laser working under this scheme exploits the quantum interference between the probability amplitudes of atomic transitions in order to eliminate absorption without disturbing the stimulated emission.^[3] This phenomenon is also the essence of electromagnetically induced transparency.^[4]

The basic LWI concept was first predicted by Ali Javan in 1956.^{[5] [6]} The first demonstration of LWI was carried out by Marlan Scully in an experiment in rubidium and sodium at Texas A&M University, and then at NIST in Boulder.^[7]

Notes and References

1. Marvin J. Weber. Book: Handbook of Lasers . CRC Press . 2019 . 978-1-4200-5017-2 . 1151.
2. Lasers without inversion: Interference of lifetime-broadened resonances. 1989. Harris. S. E.. Physical Review Letters. 62. 1033–1036. 9. 10.1103/PhysRevLett.62.1033 . 1989PhRvL..62.1033H. 10040407.
3. Lasing without inversion. 2000. Mompart. J.. Corbalán. R.. J. Opt. B. 2. 3. 10.1088/1464-4266/2/3/201. 2000JOptB...2R...7M. R7–R24. 121209763 . https://web.archive.org/web/20200101024559/http://pdfs.semanticscholar.org/a2dd/fa99e29dbb021fb0c8fd92c5af7f15353d60.pdf. dead. 2020-01-01.
4. Scully, M., & Zubairy, M. (1997). Chapter 7. In Quantum optics (p. 220). Cambridge: Cambridge University Press.
5. Scully, M., & Zubairy, M. (1997). Chapter 7. In Quantum optics (p. 245). Cambridge: Cambridge University Press.
6. A. Javan, Phys. Rev. 107, 1579 (1956)
7. Javan, A. (2000). "On knowing Marlan". In Ode to a quantum physicist: A festschrift in honor of Marlan O. Scully. Elsevier.