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1.
The photo and cathodoluminescence of zinc oxide (ZnO) filled opal arrays, as well as ZnO nanocrystals prepared by a chemical deposition method were investigated. The photoluminescence (PL) from the arrays was studied using angular resolution. The PL spectra of the filled opal exhibited a dip corresponding to the array’s photonic band gap. ZnO nanocrystals embedded in the opal matrix demonstrated quenched excitonic emission while the opal matrix showed enhanced emission. This effect is explained by an energy transfer from ZnO nanocrystals to the opal matrix. 相似文献
2.
In this paper we discuss the strong incident angle dependence of the modification of emission in an opal structure. We study the emission with oblique incidence and find that we can control the emission properties, such as emission intensity and spectral width, just by changing the incident angle of pump light. Calculations with varying incident angles show that the band gap of the structure blue shifts with the increase of incident angle and the emission power of embedded sources is strongly determined by this gap change. In addition, the photonic band gap determines the emission spectrum. With the incident angle increasing, the width of emission spectrum increases first and then decreases. 相似文献
3.
Zhengwen Yang Dong Yan Zhiguo Song Dacheng Zhou Xue Yu Yong Yang Zhaoyi Yin Lei Yan Rongfei Wang Hangjun Wu Jianbei Qiu 《Journal of luminescence》2012,132(6):1550-1552
The SiO2: Tb, Yb inverse opals with photonic band gap at 465 or 543 nm were prepared, and an effect of photonic band gap on upconversion spontaneous emission from Tb3+ was investigated. The results show that the photonic band gap has a significant influence on the upconversion emission of the SiO2: Tb, Yb inverse opals. The upconversion luminescence of the Tb3+ ions is suppressed in the inverse opal compared with the luminescence of that of the reference sample. 相似文献
4.
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.
6.
光子晶体是介电常数(折射率)随光波长大小周期性巨大变化的人工晶体。光子晶体的诞生使人类操控光子由梦想成为现实。光子晶体结构对置于光子晶体中的荧光客体自发辐射速率和荧光强度具有重要的调制作用。与半导体晶格对电子波函数的调制相类似,光子带隙材料能够调制具有相应波长的电磁波——当电磁波在光子带隙材料中传播时,由于存在布拉格散射而受到调制,电磁波能量形成能带结构。能带与能带之间出现带隙,即光子带隙。所具能量处在光子带隙内的光子,不能进入该晶体。本文将在综述这一领域国际上的重要研究进展基础上,重点介绍本课题组在镧系氧化物三维晶体的自组装与光子带隙对稀土离子自发辐射调制方面的研究成果。 相似文献
7.
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
8.
Controlling the photoluminescence spectroscopy of quinacrine dihydrochloride by SiO_2 inverse opal photonic crystal
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Manipulation of the photoluminescence spectra of light-emitting materials doped in three-dimensional (3D) inverse opal photonic crystals is investigated. Quinacrine dihydrochloride molecules doped highly ordered SiO2 inverse opal is successfully synthesized by co-assembly combined with double-substrate vertical infiltrate method. The quinacrine dihydrochloride-doped and-undoped SiO2 inverse opals each exhibit an apparent photonic band gap (PBG) in the visible light region. Significant suppression of the emission is observed when the PBG is overlapped with the quinacrine dihydrochloride emission bands. The mechanism of suppression effect of PBG in inverse opal on the fluorescence intensity of quinacrine dihydrochloride molecules is studied. 相似文献
9.
V. N. Moiseyenko O. O. Guziy V. S. Gorelik M. P. Dergachov 《Optics and Spectroscopy》2008,105(6):919-923
The photonic dispersion, the group-velocity dispersion, the effective mass, refractive index, and the spectral distribution of the density of photonic states near the edge of the photonic stop band are numerically calculated in the one-dimensional model for photonic crystals based on synthetic opals. The fluorescence spectra of rhodamine 6G and 2,5-bis(2-benzoxazolyl)hydroquinone molecules infiltrated into a synthetic opal are measured. For both substances, it is observed that the spontaneous emission intensity in the range of the photonic stop band is appreciably suppressed. A blue shift of the fluorescence spectrum of rhodamine 6G molecules is revealed. Secondary emission of synthetic opals infiltrated with colloidal silver is observed in the Stokes range under excitation of opals by radiation at λ = 400 nm. The spectrum of the secondary emission is located in the range 450–590 nm, which contains the stop band and intervals near its edges. 相似文献
10.
I. I. Shishkin K. B. Samusev M. V. Rybin M. F. Limonov Yu. S. Kivshar’ A. Gaidukeviciute R. V. Kiyan B. N. Chichkov 《JETP Letters》2012,95(9):457-461
Three-dimensional photonic crystals with an inverted yablonovite structure have been fabricated by the direct laser writing method based on the two-photon polymerization of a photosensitive material. The correspondence of the structure of the samples to the inverted yablonovite lattice has been confirmed by scanning electron microscopy. The photonic band structure of inverted yablonovite, as well as a number of related photonic materials with an fcc lattice, has been calculated. It has been found that the photonic properties of opal and yablonovite are opposite: the complete photonic band gap appears in inverted opal and direct yablonovite and is absent in direct opal and inverted yablonovite. A method for the fabrication of ideal three-dimensional photonic structures having the complete photonic band gap in the infrared and visible spectral ranges has been discussed. 相似文献
11.
Spontaneous emission from a microwave-driven four-level atom in an anisotropic photonic crystal
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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 PBG.Interesting 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. 相似文献
12.
Photoluminescence of bare and ZnO infilled artificial opals was investigated. A presence of a photonic band gap results in distortion of the photoluminescence spectra of both the bare and ZnO infilled opal nanocomposite. Filling of the opal with ZnO resulted in a shift of the Bragg diffraction peak from 430 to 460 nm. The emission from ZnO infilled opal contains no UV photoluminescence from ZnO nanocrystals, while the ZnO nanocrystals deposited on substrate by the same method exhibit strong excitonic UV emission. Although a high temperature treatment in ambient air results in an increase in the photoluminescence intensity of the ZnO nanocrystals, the quenched behavior of the excitonic emission from ZnO nanocrystals embedded in the opal matrix remains. A domination of the artificial opal matrix intrinsic emission in the photoluminescence spectra from the untreated as well as heat treated ZnO filled opal nanocomposites is observed. 相似文献
13.
V. S. Gorelik L. I. Zlobina P. P. Sverbil’ A. A. Vedernikov Yu. P. Voinov 《Bulletin of the Lebedev Physics Institute》2016,43(3):93-97
Secondary emission spectra of globular silica photonic crystals when their surfaces were exposed to laser pulses 250 fs long at a power density to 1 TW/cm2 have been studied. Optical harmonics and plasma emission were detected in this case. For the opal matrix containing pores filled with air, in the reflection mode, the third optical harmonic with a conversion efficiency of ~10% arises. The highest conversion efficiency for exciting radiation with wavelengths of 1026 or 513 nm is implemented when the frequencies of the exciting radiation or the second harmonic are near the stop band edge. In globular photonic crystals filled with sodium nitrite or barium titanate ferroelectrics, the second optical harmonic is observed. The exciting radiation conversion efficiency to the second optical harmonic was a few percent and depended on the frequency of exciting radiation and photonic crystal globule diameters. It is found that the plasma emission intensity increases with the exciting radiation power density. The dependences of the intensity of the second and third optical harmonics on the pump intensity are constructed for various photonic crystal globule diameters. 相似文献
14.
S. G. Romanov 《Physics of the Solid State》2007,49(3):536-546
Thin opal films are prepared by crystallization in a moving meniscus, and their optical transmission spectra are recorded in polarized light and studied. It is shown that the anisotropy of light propagation in the films is unambiguously related to the photonic band structure of opal and depends on the angle of incidence, the orientation of the incidence plane with respect to the opal lattice, and the wavelength and polarization of the incident light. Azimuthal diagrams of transmitted polarized light are constructed in the range of photonic band gaps of three orders for oblique incidence of a light beam. The anisotropy is found to vary with the light wave-length independently in perpendicular polarizations. A model of the band structure of opal wherein opal is represented as an fcc lattice of close-packed spheres adequately describes the optical transmission of opal films only in the range of the first-order photonic band gap. 相似文献
15.
Yu-Jie Li Kai Xie Jing Xu Pan-Pan Du 《Applied Physics A: Materials Science & Processing》2010,99(1):117-123
By the solvent vaporization convection self-assembly method, 1.86 μm silica microspheres were assembled into a colloidal crystal
template with long-range order. High refractive index silicon was then filled in the voids of the silica template by the low
pressure chemical vapor deposition method. A 3-dimensional silicon inverse opal photonic crystal was obtained with a photonic
band gap simulated by a plane wave expansion method. Its micro modality and photonic band gap properties were characterized
by scanning electron microscopy and Fourier transform IR spectrometer. There was a good agreement between the measured spectra
and the simulated results. The tilt-angle reflectance spectra showed that an obvious reflection peak at 3319 nm stayed in
existence with different incidence directions. This result proved that silicon inverse opal has a complete photonic band gap
in the mid infrared range. This study opens up an opportunity to create Si-based photonic crystal devices for atmosphere mid
infrared photodetection. 相似文献
16.
The entanglement of a two-level atom and its radiation field near the edge of a photonic band gap is studied by using the quantum entropy. Unlike the free space case, there is a steady-state entanglement between the atom and its spontaneous emission field even when the atomic transition frequency lies outside the band gap. Moreover, the degree of entanglement, which is due to the formation of atom–photon bound dressed state, depends on the detuning of the atomic transition frequency from the photonic band edge and can be controlled by a controllable photonic band gap crystal. 相似文献
17.
S.F. Kaplan N.F. Kartenko D.A. Kurdyukov A.V. Medvedev A.G. Badalyan V.G. Golubev 《Photonics and Nanostructures》2007,5(1):37-43
The sulfide (ZnS:Mn, ZnxCd1−xS:Mn, ZnxCd1−xS:Ag) and silicate (Zn2SiO4:Mn) phosphors were synthesized directly inside the pores of synthetic opal by chemical bath deposition. These composites are perfect three-dimensional photonic crystals, which produce effective photo- and electroluminescence at room temperature. The emission spectra are considerably modified by the photonic crystal structure to become anisotropic in accordance with the photonic band gap angular dispersion. 相似文献
18.
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
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20.
M. Li P. Zhang J. Li J. Zhou A. Sinitskii V. Abramova S.O. Klimonsky Y.D. Tretyakov 《Applied physics. B, Lasers and optics》2007,89(2-3):251-255
Angular distribution of the photoluminescence from trivalent rare earth ions (Eu3+) embedded inside a magnesium silicate photonic crystal with an inverse opal structure is experimentally and theoretically
studied. The emission at frequencies near the first stop-band of the photonic crystal is shown to exhibit strong angular modulation.
The angle-dependent Eu3+ photoluminescence is numerically simulated by evaluating the fractional density of optical states in the photonic crystal,
with diffuse scattering on structural imperfections taken into account. Experimental data for the emission properties of thin
inverse opal films are shown to be in agreement with the simulation results.
PACS 42.70.Qs; 78.55.-m 相似文献