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spontaneous emission from an atom in a photonic crystal with two coherent bands

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Chinese Physics B 2012年第5期21卷 330-334页

作者：黄仙山刘海莲王东 School of Mathematics and Physics Anhui University of Technology

The dynamic and the radiative properties of an excited three-level atom embedded in an anisotropic photonic crystal with two coherent bands are *** relative position of the atom in a Wigner-Seitz cell is described with a position-dependent parameter 胃（r0）,which is used as the coherent parameter for the two *** result shows that the dynamic properties of the atomic system are not only determined by atomic transition frequencies,but also affected by the gap width and the coherence of the two *** addition,the spontaneous emission spectrum of the atomic transition in free space is *** center and the intensity of the spectrum can be obviously manipulated via the coherent parameter.

关键词： spontaneous emission photonic crystals coherent photonic reservoir

spontaneous emission of two quantum dots in a single-mode cavity

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Chinese Physics B 2013年第9期22卷 431-438页

作者：邱柳张珂李志远 Laboratory of Optical Physics Institute of PhysicsChinese Academy of Sciences

The spontaneous emission spectrum from two quantum dots （QDs） that are strongly coupled with a single-mode nanocavity is investigated using rigorous numerical calculations and simple analytical solutions of quantum dynamics. The emission spectra both from the side and along the axis of the cavity are considered. Modification of two parameters, the coupling strength and the detuning between the transition frequencies of the two quantum dots, allows us to efficiently control the shape of the spontaneous emission spectrum. Different profiles and their physical origins can be well understood in the dressed-state picture for the light-QD interaction in the on-resonance and off-resonance situations. In the on-resonance situation, the emission spectra exhibit symmetric features, and they are not altered by the asymmetry in the coupling pa- rameters. The axis spectra show two emission peaks while the side spectra have three emission peaks. In the off-resonance situation, the emission spectra always show an asymmetrical three-peak feature. When the two QDs have different decay parameters, singular features （a peak or a dip） can take place at the frequency of the cavity mode, and this is attributed to the unbalanced process of the emission and absorption of a single photon.

关键词： spontaneous emission quantum dot single-mode cavity

spontaneous emission from a microwave-driven four-level atom in an anisotropic photonic crystal

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Chinese Physics B 2016年第10期25卷 164-171页

作者：姜丽万仁刚姚治海 Changchun University of Science and Technology School of Physics and Information Technology Shaanxi Normal University

The spontaneous emission from a microwave-driven four-level atom embedded in an anisotropic photonic crystal is studied. Due to the modified density of state(DOS) in the anisotropic photonic band gap(PBG) and the coherent control induced by the coupling fields, spontaneous emission can be significantly enhanced when the position of the spontaneous emission peak gets close to the band gap edge. As a result of the closed-loop interaction between the fields and the atom,the spontaneous emission depends on the dynamically induced Autler–Townes splitting and its position relative to the *** phenomena, such as spectral-line suppression, enhancement and narrowing, and fluorescence quenching, appear in the spontaneous emission spectra, which are modulated by amplitudes and phases of the coherently driven fields and the effect of PBG. This theoretical study can provide us with more efficient methods to manipulate the atomic spontaneous emission.

关键词： anisotropic photonic crystal spontaneous emission microwave field quantum coherence

spontaneous emission of a Two-Level Static Atom Coupling with Electromagnetic Vacuum Fluctuations Outside a High-Dimensional Einstein Gauss-Bonnet Black Hole

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Chinese Physics Letters 2014年第10期31卷 5-9页

作者：张明杨战营岳瑞宏 School of Physics Northwest University Xi'an 710069 Faculty of Science Ningbo University Ningbo 315211

Using the generalized formalism of Dalibard, Dupont-Roc and Cohen-Tannoudji we investigate the spontaneous excitation of a static atom interacting with electromagnetic vacuum fluctuations outside an Einstein Gauss-Bonnet black hole in d-dimensions. It shows that spontaneous excitation does not occur in a Boulware vacuum, while exists in an Unruh vacuum and Hattie-Hawking vacuum. As to the total rate of change of the atomic energy, it does not receive the contribution from the coupling constant of the Gauss-Bonnet term at spatial infinity, only the dimensional parameter has the contribution to it. Near the event horizon, both the coupling constant and the dimension p contribute to the total rate of change of the atomic energy in all three kinds of vacuum. We discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime lastly.

关键词： spontaneous emission FLUCTUATIONS (Physics) MAGNETIC couplings GAUSS-Bonnet theorem ELECTROMAGNETIC pulses VACUUM-gages

spontaneous emission of a moving atom in a waveguide of rectangular cross section

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Chinese Physics B 2023年第2期32卷 92-96页

作者：曾静卢竞周兰 Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center of Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China

We study the spontaneous emission(SE) of an excited nonrelativistic two-level system(TLS) interacting with the vacuum in a waveguide of rectangular cross section. All TLS’s transitions and the center-of-mass motion of the TLS are taken into account. The SE rate and the carried frequency of the emitted photon for the TLS initially being at rest are obtained, it is found that in the first order of the mass M, the frequency of the emitted photon is smaller than the transition frequency of the TLS and the SE rate is smaller than the SE rate Γfof the TLS fixed in the same waveguide. The SE rate for the TLS initially being moving is obtained in the second order of the mass M. The SE rate is smaller than Γfbut it is dependent not only on the atomic mass but also on the initial momentum. The carried frequency of the emitted photon is decreased when it travels along the direction of the initial momentum, whereas it is increased when it travels in the opposite direction of the initial momentum.

关键词： spontaneous emission moving atom waveguide of rectangular cross section

spontaneous emission of a Polarized Atom in a Medium Between Two Parallel Mirrors

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Communications in Theoretical Physics 2010年第1期53卷 138-144页

作者：王德华黄凯云徐强 College of Physics Ludong University

Using the photon closed orbit theory, the spontaneous emission rate of a polarized atom in a medium between two parallel mirrors is derived and calculated. It is found that the spontaneous emission rate of a polarized atom between the mirrors is related to the atomic position and the polarization direction. The results show that in the vicinity of the mirror, the variation of the spontaneous emission rate depends crucially on the atomic polarization direction. With the increase of the polarization angle, the oscillation in the spontaneous emission rate becomes decreased. For the polarization direction parallel to the mirror plane, the oscillation is the greatest; while for the perpendicular polarization direction, the oscillation is nearly vanished. The agreement between our result and the quantum electrodynamics result suggests the correctness of our calculation. This study further verifies that the atomic spontaneous emission process can be effectively controlled by changing the polarization orientation of the atom.

关键词： spontaneous emission polarized atom closed orbit theory

spontaneous emission of two interacting atoms near an interface

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Chinese Optics Letters 2009年第10期7卷 926-930页

作者：王德华 College of Physics Ludong University

The spontaneous emission rate of two interacting excited atoms near a dielectric interface is studied using the photon closed-orbit theory and the dipole image method. The total emission rate of one atom during the emission process is calculated as a function of the distance between the atom and the interface. The results suggest that the spontaneous emission rate depends not only on the atomic-interface distances, but also on the orientation of the two atomic dipoles and the initial distance between the two atoms. The oscillation in the spontaneous emission rate is caused by the interference between the outgoing electromagnetic wave emitted from one atom and other waves arriving at this atom after traveling along various classical orbits. Each peak in the Fourier transformed spontaneous emission rate corresponds with one action of photon classical orbit.

关键词： Electromagnetic waves Orbits Photons spontaneous emission

spontaneous emission in the ellipsoidal nanocrystals

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Journal of Rare Earths 2009年第4期27卷 637-640页

作者： K.K.Pukhov General Physics Institute Russian Academy of Sciences 38 Vavilov Str.Bld.D Moscow 119991 Russia

The equation was presented for the spontaneous emission rate Anano of the two-level optical centers in the subwavelength eilipsoi- dal nanocrystals embedded in a dielectric medium. An important result was that the ratio Anano/Abulk could be estimated without recourse to a particular local-field model. On the ground of this equation the expression was derived for linestrength of electric-dipole transition in trivalent rare-earth ions. The applicability of the Judd-Ofelt equation for nanoparticles was discussed.

关键词： spontaneous emission lifetime nanocrystals Judd-Ofelt parameters rare earths

spontaneous emission Originating from Atomic BEC Interacting with a Single-Mode Quantized Field

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Communications in Theoretical Physics 2018年第6期69卷 711-721页

作者： E.Ghasemian M.K.Tavassoly Atomic and Molecular Group Faculty of Physics Yazd University

In this paper we present a general theoretical model for the interaction between a number of two-level atoms constituting Bose-Einstein condensate （BEG） and a single-mode quantized field. In addition to the usual interacting terms, we take into account interatom as well as higher-order atom-field interactions. To simplify the Hamiltonian of system, after using the Bogoliubov approximation we proceed to calculate the transformed operators of atoms and field. Then, to quantify the spontaneous emission, we get analytical expressions for the expectation value of Jz as the atomic population inversion （API）, in the cases of number and coherent states for the atomic subsystem. Our results show that the above-mentioned model interaction leads to the appearance of collapse-revival phenomenon in API. In more detail, the revival time may be tuned by adjusting the interatom interaction constant. Also, the damping process lowers the amplitude of API, but does not change the CR times for weak damping. Moreover, increasing the damping may decrease the number of CRs in a given interval of time such that no revival occurs. Briefly, it may be concluded that in the resonant case the revival times are insensitive to the change of the higher-order atom-field interaction constant and are affected only by the interatom interactions. Finally, we express that, how we can find a practical procedure to measure the quantum states of atoms in BEG.

关键词： Bose-Einstein condensate atom-field interaction spontaneous emission atomic population inversion collapse-revival phenomenon