Superradiance: the principles of generation and implementation in lasers*

Abstract

The electrodynamics of active continuous media is applied to theoretically examine collective spontaneous emission regimes of dipole oscillator ensembles. Recent experiments in which the superfluorescence phenomenon has been observed are reviewed. The focus is on propagation and interaction effects experienced by the inhomogeneous waves of active center polarization and electromagnetic fields. The superradiant laser dynamics is examined and prospects for the realization of superradiant lasers using low-Q cavities are discussed.

Comparative Analysis of the Dynamical Spectra of a Polarization of an Active Medium and an Electromagnetic Field in the Superradiant Heterolasers

“…In the case of superradiant lasers with a strong inhomogeneous broadening of spectral line exceeding the cooperative frequency, when Δ 0 >> 1 > −1 >> −1 2 , there are at least five qualitatively different operation regimes of lasing: quasi-stationary, selfmodulation, regular pulsed, irregular pulsed with quasiperiodic pulse trains, and quasistochastic [1,4,5]. Which regime occurs and how it looks like depend on a cavity length , the pumping level and rate 1 , and a spectrum of lasing modes.…”

“…As shown in the recent review [1], the experimental evidences of a super-fluorescence (collective spontaneous emission under a pulsed pumping) give prospects for the creation of the superradiant heterolasers with continuous-wave (CW) incoherent pumping. As is well-known, in this class of lasers, the superradiance condition reads ″ 0 > −1 2 , where ″ 0 ≈̄2 − 1/ 2 − 1/ * 2 is the growth rate of the most unstable hot mode, = √2 2 21 0 Γ/( 0 ℏ) the cooperative frequency,̄the population inversion (normalized to unity) of the active centers averaged over a cavity, 0 their density, a photon lifetime for a given cavity mode, Γ the mode-filling factor, 0 the dielectric (real) permittivity of a background medium (matrix), 21 the central frequency of a spectral line of active centers, their dipole transition moment, 2/ 2 and 2/ * 2 the homogeneous and inhomogeneous line broadening (see also [2,3]).…”

“…The one-dimensional integro-differential semiclassical equations of the spatialtemporal dynamics of the superradiant laser may be written out in the form [1,5]…”

Quantum theory of superfluorescence based on two-point correlation functions

“…Ref. [11], [12], [13], [14] and references therein). The complexity of the problem was described in Ref.…”

Intensity-correlated spiking of infrared and ultraviolet emission from sodium vapors

“…The effect of cooperative emission is also known as superfluorescence or superradiance, depending on initial conditions and peculiarities of excitation [2]. Thoroughly studied cooperative emission was reported in various systems ranging from phased antenna arrays [3] and Josephson junctions [4] to warm [5] and laser cooled atomic samples [6], active continuous media [7], quantum dots and diamond nanocrystals [8,9].…”