Quantum theory of multiphoton lasers

H. J. Carmichael, K. J. McNeil, Daniel F. Walls

K. J. McNeil, Daniel F. Walls

A quantum-mechanical model for a multiphoton laser is proposed by an obvious generalization of the usual one-photon laser model. The authors consider a class of lasers which preserve detailed balance. This condition is ensured by assuming a multiphoton loss mechanism for the laser light of the same order as the multiphoton gain from the stimulated emission process. Solutions for the stationary density operator of the light field are obtained by a straightforward generalization of the techniques of Scully and Lamb. The multiphoton laser around threshold exhibits behaviour analogous to a second-order phase transition. A non-thermal distribution of multiphoton laser light is achieved above threshold.

Wang Zhi Cheng, Hermann Haken

Davıd L. Andrews

The pulsed output obtainable from a mode-locked laser has usually been described using classical radiation theory. A quantised-field representation is developed and utilised in a discussion of multiphoton ionisation. The assumptions made in deriving the results are critically examined, and a modification of the theory to deal with other kinds of pulsed radiation is indicated.

Joseph H. Eberly

Recent observations allow the first quantitative tests of the ability of theories of multiphoton-resonant processes to deal with Doppler, laser and collisional broadening in bound-bound transitions. The predictions of a certain extended two-level (ETL) model of multiphoton-resonant phenomena are compared with these observations.