Sub-Poissonian quantum-beat laser without inversion

Abstract

Using the 'dressed-atom-dressed-mode' approach and separating the decoupled atomic state, we investigate the statistical properties of a quantum-beat laser without inversion. While the fluctuations of the relative amplitude and phase are retained at their vacuum noise levels, the intensity fluctuations in the sum mode are reduced below the shot noise limit with an optimum Mandel parameter Q = − 1 2 when the laser is operated well above threshold. In particular, we show that the decoupled atomic state significantly relaxes the parameter requirement for squeezing. The physical cause is also explained.

Quantum noise reduction in a laser by cascade coherent excitation

“…Production of squeezed light from a laser as an active device has been an important and interesting subject and has received considerable attention. It has been shown that a laser based on quantum coherence and interference [1][2][3][4][5][6][7] and even a conventional laser with an incoherent pump [8][9][10] can produce sub-Poissonian light [1][2][3][4][5][6][7][8][9][10]. The basic principle is that a sequence of incoherent and/or coherent steps leads to the recycling of active electrons and regularization of the laser excitation process.…”

Quadripartite square graph-state entanglement via atomic coherent effects in two-photon resonant systems

“…k (γ l , κ j , |g j a j |), k, l = 1, 2; j = 1-4. On the other hand, the multimode interaction can be treated by introducing four collective modes [28,29]. This will reduce the fourmode system to an equivalent two-mode one.…”

“…Second, quantum beats appear in three-channel two-photon processes, which is completely different from the usual cases. Usually, quantum beats appear when photons are emitted from neardegenerate excited states to a common ground state or from a common excited state to near-degenerate lower states [27][28][29][30][31]. It has been shown that for a quantum-beat laser, spontaneous emission is so highly correlated that it no longer contributes to the relative phase and the relative amplitude.…”

Carrier-envelope phase control of electron motion in laser-driven H32+

“…The choice of H 3 2+ as a model system is motivated by its simplicity; H 3 2+ may be said to be the simplest possible triatomic system. The laser-driven electron dynamics in H 3 2+ with fixed nuclei has been studied in [57][58][59][60][61][62][63][64], and recently with moving nuclei (two degrees of freedom) [65,66]. The more complex two-electron system H 3 + with stationary nuclei has also been investigated [58,61,[67][68][69], calculations for H 3 + with classically moving nuclei have been performed with a quasiclassical model [70] and with time-dependent density functional theory [71].…”