Quantum Theory of Laser Amplifiers.

A standard laser beam has photon degeneracy, or coherence, $\mathfrak{C}$ , of at most $8μ^2$ , where $μ$ is the number of photons in the laser itself. Even quantum-engineered lasers, if required to produce a beam with the standard statistical properties, have limited coherence, scaling as $μ^4$ . Moreover, such lasers (still unrealised) require very unconventional gain and output-coupling mechanisms. Here, we propose a different path to increasing $\mathfrak{C}$ : cascaded linear amplifiers, with conventional couplings. By dropping the requirement on the beam's properties, this approach can, in theory, achieve $\mathfrak{C}$ scaling exponentially in $μ$ . Here $μ$ is the total source excitation number, across all the amplifiers. Two amplifiers suffice to surpass the standard $μ^2$ scaling.A standard laser beam has photon degeneracy, or coherence, $\mathfrak{C}$, of at most $8μ^2$, where $μ$ is the number of photons in the laser itself. Even quantum-engineered lasers, if required to produce a beam with the standard statistical properties, have limited coherence, scaling as $μ^4$. Moreover, such lasers (still unrealised) require very unconventional gain and output-coupling mechanisms. Here, we propose a different path to increasing $\mathfrak{C}$: cascaded linear amplifiers, with conventional couplings. By dropping the requirement on the beam's properties, this approach can, in theory, achieve $\mathfrak{C}$ scaling exponentially in $μ$. Here $μ$ is the total source excitation number, across all the amplifiers. Two amplifiers suffice to surpass the standard $μ^2$ scaling.

quant-pharXiv:2607.28716Aug 3, 20260 citations

Theory of Relaxation Spikes in Two-Level Laser Amplifiers

H. A. Trenchard

Quantum ElectronicsJan 1, 19640 citations

Quantum Theory of Laser

Masahiko HIROOKA, Sigenobu Sunakawa

The Review of Laser EngineeringJan 1, 19860 citations

Analysis of laser-amplifier noise: A review of the method and its application to optical communications

Kazuro Kikuchi

This study summarizes the theory of laser-amplifier noise based on the master equation, the quantum-mechanical Langevin equation, and the rate equation. The three approaches are used differently depending on the application. Laser-amplifier noise in the direct-detection receiver is described by the master equation. Meanwhile, the quantum-mechanical Langevin equation is most effective for analyzing noise appearing in coherent optical communication systems. The rate equation approach provides a clear understanding of the intensity-noise characteristics of laser oscillators, including the amplitude squeezing.This study summarizes the theory of laser-amplifier noise based on the master equation, the quantum-mechanical Langevin equation, and the rate equation. The three approaches are used differently depending on the application. Laser-amplifier noise in the direct-detection receiver is described by the master equation. Meanwhile, the quantum-mechanical Langevin equation is most effective for analyzing noise appearing in coherent optical communication systems. The rate equation approach provides a clear understanding of the intensity-noise characteristics of laser oscillators, including the amplitude squeezing.

Jun 6, 20230 citations

Quantum Theory of a Laser

Pierre Meystre, Murray Sargent

Springer eBooksJan 1, 19903 citations

A standard laser beam has photon degeneracy, or coherence,

\mathfrak{C}

, of at most

8μ^2

, where

μ

is the number of photons in the laser itself. Even quantum-engineered lasers, if required to produce a beam with the standard statistical properties, have limited coherence, scaling as

μ^4

. Moreover, such lasers (still unrealised) require very unconventional gain and output-coupling mechanisms. Here, we propose a different path to increasing

\mathfrak{C}

: cascaded linear amplifiers, with conventional couplings. By dropping the requirement on the beam's properties, this approach can, in theory, achieve

\mathfrak{C}

scaling exponentially in

μ

. Here

μ

is the total source excitation number, across all the amplifiers. Two amplifiers suffice to surpass the standard

μ^2

scaling.