QUANTUM OPTICS OF LOCALIZED LIGHT IN A PHOTONIC BAND-GAP
QUANTUM OPTICS OF LOCALIZED LIGHT IN A PHOTONIC BAND-GAP
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DOI：
10.1103/physrevb.43.12772
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发表时间：
1991-06-01
影响因子：
3.7
通讯作者：
WANG, J
中科院分区：
文献类型：
--
作者：
JOHN, S;WANG, J
我们描述了一类强散射介质材料中光子与类氢原子和分子相互作用的量子电动力学。这些介质由有序或接近有序的球面散射体阵列组成，具有真正的正折射率，在电磁传播的所有方向上都显示出完整的光子带隙或伪带隙。对于跃迁频率在禁带中的类氢原子，我们证明了光子-原子束缚态的存在和稳定性。当带隙与中心频率之比约为5%时，光子局域长度Zeta-loc大于或等于1ol，其中L是介质阵列的晶格常数。原子自身的局域辐射场的这种强烈的自修饰导致了反常的Lamb位移，当跃迁频率位于光子能带边缘附近时，激发的原子能级分裂成双重态。我们估计在真空跃迁能下，这种分裂的大小为10(-6)。研究了这种光子束缚态相对于电磁和振动衰变机制的稳定性。对于嵌入介电结构固体部分的孤立分子，吸收和自发发射的主要机制是通过光驱动的电子-声子相互作用以及由此产生的声子吸收和发射边带。禁止通过光子-声子相互作用将局域光子直接拉曼或布里渊散射到传播模，或反之亦然。对于不与介电主体的固体部分接触的原子，电磁双光子自发辐射率在几天的尺度上。对于光子带隙内相距R的两个完全相同的原子，激发原子向非激发原子的能量传递是通过相移共振偶极-偶极相互作用实现的，这种相互作用在R>；zeta-loc中指数为零。当存在有限密度的原子时，这导致在禁带内形成一个窄的光子杂质带。该杂质带表现出一种不同的非线性光学性质。当相邻的两个原子都被激发时，单光子自发辐射在大约2hbar-omega-0处通过三级电磁过程发生，速率伽马近似为α-3-omega-0(α-0/R)8，其中α-0是原子的玻尔半径，α是精细结构常数。
We describe the quantum electrodynamics of photons interacting with hydrogenic atoms and molecules in a class (of strongly scattering dielectric materials. These dielectrics consist of an ordered or nearly ordered array of spherical scatterers with real positive refractive index and exhibit a complete photonic band gap or pseudogap for all directions of electromagnetic propagation. For hydrogenic atoms with a transition frequency in the forbidden optical gap, we demonstrate both the existence and stability of a photon-atom bound state. For a band gap to center frequency ratio DELTA-omega/omega-0 approximately 5%, the photon localization length zeta-loc greater-than-or-equal-to 1OL, where L is the lattice constant of dielectric array. This strong self-dressing of the atom by its own localized radiation field leads to anomalous Lamb shifts and a splitting of the excited atomic level into a doublet when the transition frequency lies near a photonic band edge. We estimate the magnitude of this splitting to be 10(-6) at the vacuum transition energies. The stability of this photon-bound state with respect to electromagnetic as well as vibrational decay mechanisms is examined. For an isolated molecule embedded in the solid fraction of the dielectric structure, the dominant mechanism for absorption and spontaneous emission is via optically driven electron-phonon interactions and the resulting phonon-absorption and -emission sidebands. Raman or Brillouin scattering of a localized photon into a propagating mode, or vice versa, directly by photon-phonon interaction is forbidden. For atoms not in contact with the solid fraction of the dielectric host, the electromagnetic two-photon spontaneous emission rate is on the scale of several days. For two identical atoms separated by a distance R within the photonic band gap, energy transfer from an excited atom to an unexcited atom occurs by a phase-shifted resonance dipole-dipole interaction which vanishes exponentially for R > zeta-loc. This leads to the formation of a narrow photonic impurity band within the gap when a finite density of atoms is present. This impurity band exhibits a different kind of nonlinear optical properties. When two neighboring atoms are both excited, single-photon spontaneous emission at approximately 2hBAR-omega-0 occurs by a third-order electromagnetic process with rate GAMMA approximately alpha-3-omega-0(alpha-0/R)8, where alpha-0 is the atomic Bohr radius and alpha is the fine-structure constant.