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1.
Spontaneous emission from GaAs/AlGaAs quantum dots (QDs) embedded in photonic crystals with a narrow photonic band gap is studied theoretically. The results show that the decay lifetime is very sensitive to the sizes of QDs, and both inhibited and accelerated emission can occur, which had been indicated in a previous experiment. The Weisskopf–Wigner approximation, good for atoms and molecules, may be incorrect for QDs. A damped Rabi oscillation of the excited state with the transition frequency outside the photonic band gap may appear, which is impossible for atoms and molecules. 相似文献
2.
Absolute band gap properties in two-dimensional photonic crystals composed of air rings in anisotropic tellurium background 总被引:1,自引:0,他引:1
B. Rezaei T. Fathollahi Khalkhali A. Soltani Vala M. Kalafi 《Optics Communications》2009,282(14):2861-1992
We analyze the band gap spectra of two-dimensional photonic crystals created by square, triangular and honeycomb lattices of air rings with different geometrical shapes and orientations in anisotropic tellurium background. Specifically, five different shapes of rings (circular, hexagonal, elliptical, rectangular and square) are considered. Using the numerical plane wave method, we discuss the maximization of the absolute photonic band gap width as a function of air ring parameters with different shapes and orientations in three types of lattices. 相似文献
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Yang Zhengwen Kan Zhu Zhiguo Song Xue Yu Dacheng Zhou Zhaoyi Yin Lei Yan Qiu Jianbei 《Applied Physics A: Materials Science & Processing》2011,103(4):995-999
Upconversion (UC) emission properties of Yb, Er co-doped lead lanthanum titanate inverse opal photonic crystals were investigated.
The results showed that the photonic band gap has a significant influence on the upconversion emission of Yb, Er co-doped
lead lanthanum titanate inverse opal photonic crystals. Significant suppression of the upconversion emission was detected
if the photonic band gap overlapped with the Er3+ ions emission band. 相似文献
5.
V.P. Kandidov A.E. Dormidonov O.G. Kosareva N. Akozbek M. Scalora S.L. Chin 《Applied physics. B, Lasers and optics》2007,87(1):29-36
The geometric phase of a three-level atom interacting with single-mode in the presence of the one-dimensional photonic band
gap material is studied. We consider dipole emitters situated in the thin slab region between two semi-infinite one-dimensionally
periodic photonic crystals, a situation reminiscent of planar cavity laser structures. It shows that the Pancharatnam phase
depends crucially on the presence of the photonic band gap. This feature is attributed to the fact that in the photonic band
gap region electromagnetic modes are not allowed to propagate into the dielectric slab and hence no interaction can take place
in this region. The outcomes are illustrated with numerical simulations applied to GaAs.
PACS 03.67.-a; 32.80.Pj; 42.50.Ct; 42.65.Yj; 03.75.-b 相似文献
6.
G. J. Pert 《Contemporary Physics》2013,54(4):303-306
In the first part of this introductory review we outline the developments in photonic band gap materials from the physics of photonic band gap formation to the fabrication and potential applications of photonic crystals. We briefly describe the analogies between electron and photon localization, present a simple model of a band structure calculation and describe some of the techniques used for fabricating photonic crystals. Also some applications in the field of photonics and optical circuitry are briefly presented. In the second part, we discuss the consequences for the interaction between an atom and the light field when the former is embedded in photonic crystals of a specific type, exhibiting a specific form of a gap in the density of states. We first briefly review the standard treatment (Weisskopf?–?Wigner theory) in describing the dynamics of spontaneous emission in free space from first principles, and then proceed by explaining the alterations needed to properly treat the case of a two-level atom embedded in a photonic band gap material. 相似文献
7.
X. Ma 《Applied physics. B, Lasers and optics》2006,84(1-2):339-341
Monodispersed silica microspheres of 270 nm are synthesized by a colloidal solution method. Larger scale perfect three-dimensional
photonic crystals (PCs) are rapidly prepared using the evaporation of acetone to self-assemble the microspheres on quartz
substrates by vertical deposition methods. We find that the pseudo-photonic band gap (PBG) of the PC structure changes with
increasing annealing temperature; it drastically shifts from 450 nm for as-grown crystals to 409 nm for annealing at 800 °C.
CdS photonic crystals are formed by infiltrating CdS nanocrystals of 6 nm into the SiO2 PC structure. The transmission and spontaneous emission characteristics of CdS PCs have been investigated. The clear dip
in the spontaneous emission spectrum relates to the photonic band gap of CdS PCs, indicating that the spontaneous emission
is inhibited in the region of the PBG. The emission band of CdS PCs becomes narrower and sharper than that of CdS nanocrystals;
this demonstrates that the emission band and intensity of the luminescent devices will be tuned by controlling the position
of the PBG.
PACS 42.70.Qs; 42.25.Bs; 78.20.-e; 78.55.Et 相似文献
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Localized fields in the defect mode of one-dimensional photonic crystals with active impurity are studied with the help of the theory of spontaneous emission from two-level atoms embedded in photonic crystals.Numerical simulations demonstrate that the enhancement of stimulated radiation, as well as the phenomena of transmissivity larger than unity and the abnormality of group velocity close to the edges of photonic band gap, are related to the negative imaginary part of the complex effective refractive index of doped layers. This means that the complex effective refractive index has a negative imaginary part, and that the impurity state with very high quality factor and great state density will occur in the photonic forbidden band if active impurity is introduced into the defect layer properly. Therefore, the spontaneous emission can be enhanced, the amplitude of stimulated emission will be very large and it occurs most probably close to the edges of photonic band gap with the fundamental reason, the group velocity close to the edges of band gap is very small or abnormal. 相似文献
10.
Hoeppe U Wolff C Küchenmeister J Niegemann J Drescher M Benner H Busch K 《Physical review letters》2012,108(4):043603
Since the very first proposition of photonic crystals, their influence on the dynamics of spontaneous emission has been of great interest. The radiation dynamics is described by an integration kernel which--in a spectral representation--comprises two equally important contributions: the Lamb shift and the radiative contribution to the linewidth. The latter is connected to the density of states via Fermi's golden rule. To our knowledge, we present the first spatially resolved measurement of the complete radiation dynamics in a photonic crystal and of its local density of states over a wide spectral range. To this end we study a single magnetic dipole situated in a photonic crystal with a band gap at microwave frequencies and find non-Markovian behavior in excellent agreement with ab initio calculations. 相似文献
11.
We have investigated the switching mechanism due to the spontaneous emission cancellation in a photonic band gap (PBG) material doped with an ensemble of four-level nano-particles. The effect of the dipole–dipole interaction has also been studied. The linear susceptibility has been calculated in the mean field theory. Numerical simulations for the imaginary susceptibility are performed for a PBG material which is made from periodic dielectric spheres. It is predicted that the system can be switched between the absorbing state and the non-absorbing state by changing the resonance energy within the energy bands of the photonic band gap material. 相似文献
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A. Hatef 《Optics Communications》2011,284(9):2363-5383
In this paper we have developed a theory for the decay of a quantum dot doped in a two-dimensional metallic photonic crystal consisting of two different metallic pillars in an air background medium. This crystal structure forms a full two-dimensional photonic band gap when the appropriate pillar sizes are chosen. The advantage of using two metals is that one can easily control the density of states and optical properties of these photonic crystals by changing the plasma energies of two metals rather than one. Using the Schrödinger equation method and the photonic density of states, we calculated the linewidth broadening and the spectral function of radiation due to spontaneous emission for two-level quantum dots doped in the system. Our results show that by changing the plasma energies one can control spontaneous emission of quantum dots doped in the metallic photonic crystal. 相似文献
14.
Mahmoud Abdel-Aty 《Applied physics. B, Lasers and optics》2005,81(2-3):193-203
This communication is an enquiry into the circumstances under which concurrence and phase entropy methods can give an answer to the question of quantum entanglement in the composite state when the photonic band gap is exhibited by the presence of photonic crystals in a three-level system. An analytic approach is proposed for any three-level system in the presence of photonic band gap. Using this analytic solution, we conclusively calculate the concurrence and phase entropy, focusing particularly on the entanglement phenomena. Specifically, we use concurrence as a measure of entanglement for dipole emitters situated in the thin slab region between two semi-infinite one-dimensionally periodic photonic crystals, a situation reminiscent of planar cavity laser structures. One feature of the regime considered here is that closed-form evaluation of the time evolution may be carried out in the presence of the detuning and the photonic band gap, which provides insight into the difference in the nature of the concurrence function for atom-field coupling, mode frequency and different cavity parameters. We demonstrate how fluctuations in the phase and number entropies affected by the presence of the photonic-band-gap. The outcomes are illustrated with numerical simulations applied to GaAs. Finally, we relate the obtained results to instances of any three-level system for which the entanglement cost can be calculated. Potential experimental observations in solid-state systems are discussed and found to be promising. 相似文献
15.
论证了在赝带隙光子晶体中存在一个全频率域态总数守恒规则,在完全带隙光子晶体中还存在一个局域态总数守恒规则.态总数守恒规则指出,如果一个光子晶体的态密度在某些频率范围存在相对于等效介质态密度的谷,则一定由其他频率范围内相对于等效介质态密度的峰来补偿.使用符合态总数守恒规则的态密度模型,解释了态密度调制导致的自发辐射谱增强、抑制、变窄、红移、蓝移以及谱分裂等光子晶体中的量子光学现象.该理论比较适合研究在具有赝带隙的光子晶体中大量随机分布的发光原子或分子的自发辐射行为.
关键词:
光子晶体
自发辐射
态密度
光子赝带隙 相似文献
16.
In this paper, we have studied two-dimensional function photonic crystals, in which the dielectric constants of medium columns are the functions of space coordinates , that can become true easily by electro-optical effect and optical kerr effect. We calculated the band gap structures of TE and TM waves, and found the TE (TM) wave band gaps of function photonic crystals are wider (narrower) than the conventional photonic crystals. For the two-dimensional function photonic crystals, when the dielectric constant functions change, the band gaps numbers, width and position should be changed, and the band gap structures of two-dimensional function photonic crystals can be adjusted flexibly, the needed band gap structures can be designed by the two-dimensional function photonic crystals, and it can be of help to design optical devices. 相似文献
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Laser-induced emission from rhodamine-B dye embedded in pseudo band gap opaline photonic crystals is discussed. The photonic crystals are fabricated using rhodamine-B doped polystyrene colloids and show 65% reflectance at the stop band centered at 604 nm. The reflectance of the crystal is increased to 74% by coating with a thin layer of gold. Both spontaneous and stimulated emissions of the dye are observed in the photonic stop band environment by exciting the crystal with the second harmonic (532 nm) of a Q-switched Nd:YAG laser. The thin layer of gold functioned as a high reflecting end mirror to the dye-doped cavity when the crystal is pumped from the substrate side. Angle-dependent suppression at the stop band wavelength is observed in the spontaneous emission of the dye. Spectrally narrow stimulated emission and lasing is achieved in the gold coated dyed PhC at a threshold pump power of 60 mW in a selective direction of 22° from the direction of excitation. By studying emission from several photonic crystals with different number of layers, it is concluded that a sharp threshold for lasing is not observed in uncoated photonic crystals when they contained fewer than 30 ordered layers and lesser than 70% reflectance. 相似文献
19.
S. Bayan U. Das D. Mohanta 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(2):463-468
Barbules of the peacock feather have been used as the
natural template for developing assemblies of zinc oxide (ZnO) nanospheres.
The different colored barbules consisting of various photonic crystals
(extracted from eye-pattern) were characterized in terms of the stop-bands
identified in the respective Reflectance spectra. The stop-bands of the
photonic crystals are found to get red-shifted after the loading of ZnO
nanospheres and was reasoned to the modification of photonic band gap. The
ZnO nanosphere decorated barbules show well defined photoluminescence
response with dominant defect related emission of ZnO. The artificially
grown inorganic structures on natural templates form a basis of new hybrid
system that can help in exploiting photonic band gap engineering and light
wave modulation with high selectivity. 相似文献
20.
K. M. Morozov K. A. Ivanov A. R. Gubaydullin M. A. Kaliteevski 《Optics and Spectroscopy》2017,122(2):235-242
The change in probability of spontaneous emission for emitter placed in one-dimensional photonic quasicrystal (optical Fibonacci lattice) was examined. When the dipole is placed in Fibonacci lattice two different scenarios can be expected: enhancing (if frequency and direction of the dipole emission correspond to optical eigenmode of structure, and position corresponds to maximum value of modes electric field profile) or suppression (in case of photonic band gap) of spontaneous emission rate. Fact that both effects are expressed in quasicrystals less than in the Bragg reflectors and in the microcavities was demonstrated. 相似文献