Hannover 2010 – scientific programme

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SYLA: Symposium 50 Years of Lasers

SYLA 1: 50 Years of Lasers I

SYLA 1.2: Invited Talk

Wednesday, March 10, 2010, 14:30–15:00, E 415

The origin of the quantum theory of lasing — •Fritz Haake — Universität Duisburg-Essen

The realization of the laser in 1960 was followed by intensive theoretical work worldwide. Hermann Haken and his Stuttgart school pioneered the quantum treatment in terms of nonlinear Langevin equations. A Schrödinger-picture description by master equations followed.The qualitative picture of slow phase diffusion and a rather stable modulus of the light-mode amplitude emerged. The near-threshold behavior was captured by a Fokker-Planck equation for a van der Pol type oscillator.

The analogy of the laser threshold with critical points of second-order phase transitions was discovered and the field of non-equilibrium phase transitions thus inaugurated. Further ramifications included the extension of the basic ideas towards chemical, biological, and even social systems.

The quantum theory of lasing came into new blossom when in the nineties lasers were pushed to the quantum noise limit and light squeezing was implemented.