共查询到20条相似文献,搜索用时 531 毫秒
1.
The spectra of secondary emission of a globular photonic crystal such as the opal matrix filled with the POPOP aromatic compound (a known luminophore) and initial materials excited by semiconductor light-emitting diodes were studied. It was found that the luminescence spectrum of opal filled with POPOP significantly differs from luminescence spectra of POPOP itself and initial opal. It was shown that the observed luminescence in the visible region is mostly caused by three-photon parametric light scattering. In this case, the spectral shape is controlled by the photon density of states, differing from the photon density of states of pure opal. The shape of the secondary emission spectrum of artificial opal filled with POPOP was calculated. The effect of the photonic bandgap position on the intensity distribution of spontaneous emission of used luminophore was established. 相似文献
2.
Benjamin Gesemann Stefan L. Schweizer Ralf B. Wehrspohn 《Photonics and Nanostructures》2010,8(2):107-111
We present measurements of the thermal emission properties of 2D and 3D silicon photonic crystals with and without substrate heated resistively as well as passively with an aluminium hotplate. The out-of-plane and in-plane emission properties were recorded and compared to numerical simulation. It turned out that for the in-plane 2D photonic crystal and out-of-plane 3D photonic crystal emission a photonic stop gap effect is visible. For the out-of-plane 2D photonic crystal emission, no photonic bandgap effect is observable but instead strong silicon oxide emission from native oxide inside the pores of silicon are observable. A model for the modified thermal emission is presented. 相似文献
3.
Zhengwen Yang 《Solid State Communications》2011,151(5):364-367
Inverse opal photonic crystals of Y b3+, Er3+ co-doped TiO2 (TiO2:Yb, Er) were prepared by a self-assembly technique in combination with a sol-gel method. Upconversion (UC) luminescence properties of the inverse opals were investigated. The results show that photonic bandgap has significant influence on the upconversion emission of the TiO2:Yb, Er inverse opal photonic crystals. Significant suppression of the upconversion emission was detected if the photonic bandgap overlapped with the Er3+ ions emission band. 相似文献
4.
The angular dependence of the spontaneous emission of CdTe quantum dots (QDs) inside a photonic crystal with a pseudogap is reported. The sensitive dependences of the radiative lifetime and the photoluminescence spectrum of CdTe QDs on the observation angle demonstrate the effect of the photonic bandgap on the spontaneous emission of the QDs. 相似文献
5.
异质镜像光子晶体的光子带隙研究 总被引:1,自引:0,他引:1
对异质镜像结构光子晶体(ABCCBA)N进行了研究。首先,利用一维介电体系中处理光传播的方法--传输矩阵法,详细推导了异质镜像光子晶体透射率的计算公式;然后,采用Matlab软件编程仿真并分析了光子带隙形成与镜像周期数目、光子带隙数目与光子晶体薄层厚度、光子带隙位置与入射角大小等的关系。结果表明:光子带隙的形成及变化主要受光子晶体薄层厚度及入射角大小变化的影响。通过改变影响光子晶体光子带隙的参数,可得到不同频段的光子带隙,用来制作高质量反射镜、滤波器和发光二极管等。 相似文献
6.
V. A. Trofimov M. V. Fedotov A. G. Volkov N. V. Tcherniega V. V. Savranskii S. Lan 《Laser Physics》2010,20(5):1137-1143
Recently, in papers [1, 2] were described the effect of long-time emission of photonic crystal (synthetic opals) under the
action of nanosecond laser pulse. The duration of the luminescence is of the order of seconds. Despite on the other phenomena,
which were considered in these papers, below we focus our attention on possible explanation of long time emission from nonlinear
photonic crystal. The basis of our consideration is papers [3, 4], those deal with soliton formation in several layers of
1D nonlinear photonic crystal. Because of this, the light wave can exist in photonic crystal a long time (in ideal case—infinite
time interval). Taking into account a relation between soliton duration and its maximum intensity, the leaving of laser energy
from the layer of photonic crystal takes place due not full reflection from boundaries of layer. The time of light emission
for this case depends on nonlinear susceptibility of photonic crystal and the intensity of laser pulse. Hence, soliton formation
inside the nonlinear elements of photonic crystal can be one of the reasons of long time emission. We got in computer simulation
a long time emission of 1D (layered) and 2D (circular or rectangular elements) nonlinear photonic crystal under the action
of laser pulse with femtosecond duration under the conditions of soliton formation in some elements of photonic crystal. Input
intensity of laser pulse, at which a soliton appears in nonlinear photonic crystal, can be ten times less due to effects of
enhancement of optical intensity in periodic structure [4, 5]. 相似文献
7.
Partial bandgap characteristics of parallelogram lattice photonic crystals are proposed to suppress the radiation modes in a compact dielectric waveguide taper so as to obtain high transmittance in a large wavelength range. Band structure of the photonic crystals shows that there exists a partial bandgap, The photonie crystals with partial bandgap are then used as the cladding of a waveguide taper to reduce the radiation loss efficiently. In comparison with the conventional dielectric taper and the complete bandgap photonic crystal taper, the partial bandgap photonic crystal taper has a high transmittance of above 85% with a wide band of 170 nm. 相似文献
8.
P. V. Dolganov S. O. Gordeev V. K. Dolganov 《Journal of Experimental and Theoretical Physics》2014,118(6):891-895
The reflection spectra of a cholesteric photonic crystal have been measured. The experimental spectra are described by a theoretical expression that follows from the analytical solution of the Maxwell equations. The photonic bandgap width Δν has been determined. The photonic bandgap width changes abruptly as the position of the diffraction band changes. The temperature dependence of the relative bandgap width Δν/ν0 and the order parameter for a photonic crystal are described by Landau’s theory of phase transitions. 相似文献
9.
《Laser \u0026amp; Photonics Reviews》2013,7(1):NA-NA
The image depicts a silicon photonic crystal nanocavity light emitting diode, which operates in the 1300–1600 nm wavelength range. The emission is based on defect luminescence. The optically active defects, shown in the inset, are created by hydrogen plasma treatment. The emission from these defects is strongly enhanced by the photonic crystal cavity. (Picture: A. Shakoor et al. 10.1002/lpor.201200043 , pp. 114–121, in this issue) 相似文献
10.
We report the fabrication and characterization of a new type all-solid photonic bandgap fiber. By introducing an index depressed layer around the high-index rod in the unit cell of photonic crystal cladding, transmission loss as low as 2 dB/km within the first bandgap is realized for the all-solid photonic bandgap fiber with a bandwidth of over 700 nm. The bend loss experiment shows that the photonic bandgap fiber is much less bend sensitive than single-mode fiber. 相似文献
11.
The effect of dielectric constant contrast and the filling factor to the photonic bandgap in a 2-D square lattice photonic crystal is discussed. The location, width and number of photonic bandgap can be modulated. 相似文献
12.
通过溶剂蒸发对流自组装法制备SiO2胶体晶体,采用低压化学气相沉积法填充Si,制备得到Si反蛋白石(opal)三维光子晶体.采用扫描电子显微镜对Si反opal的显微形貌进行表征,采用平面波展开法理论模拟Si反opal的光子带隙,采用傅里叶变换红外光谱仪测试其光学性能.研究结果表明:Si在SiO2微球空隙内填充致密均匀,显微红外光谱测试的光子带隙反射峰位置及带宽与理论计算基本符合.变角度反射光谱测试表明,Si反opal沿不同角度入射时在中心波长3319nm处均存在明显的反射峰,证明其具有完全光子带隙,带隙位于中红外大气窗口区域. 相似文献
13.
Photonic crystal, a novel and artificial photonic material with periodic dielectric distribution, possesses photonic bandgap
and can control the propagation states of photons. Photonic crystal has been considered to be a promising candidate for the
future integrated photonic devices. The properties and the fabrication method of photonic crystal are expounded. The progresses
of the study of ultrafast photonic crystal optical switching are discussed in detail. 相似文献
14.
The third-order Kerr nonlinear optical effect of a one-dimensional photonic bandgap structure of a cholesteric liquid crystal is investigated. In a femtosecond nonlinear transmission measurement, nonlinear optical changes in the bandgap edges are observed. From analysis of the dispersion relation, Kerr nonlinear coefficients of nematics, forming the cholesteric liquid crystal, are found to be enhanced by 1-2 orders of magnitude through the photonic bandgap structure. 相似文献
15.
We demonstrate an electrically tunable Sagnac filter based on a photonic bandgap fiber that is realized by infusing liquid crystal into a solid-core air-hole photonic crystal fiber. The filter enables an electrical tuning with a range of about 26 nm for one single interference minimum in the transmission bandgap from 1330 to 1650 nm wavelength. The tuning efficiency is averaged to 0.53 nm/V. 相似文献
16.
A novel method to enlarge the zero-effective-phase bandgap has been presented in the one-dimensional photonic crystals by
sandwiching the third material between the two single-negative materials to form a one-dimensional ternary periodic structure.
The band-edges formula for the one-dimensional ternary photonic crystal is derived based on the effective-medium theory and
the expressions of the upper and lower frequency limits for the ternary photonic crystals are obtained. Then two schemes to
enlarge the zero-effective-phase bandgaps are put forward. Moreover, the angular- and polarization-dependences of the photonic
bandgap are investigated. Finally, the role of the dispersion in the sandwiched layer on the bandgap extending has been discussed
and two schemes are also presented to enlarge the zero-effective-phase photonic bandgap. 相似文献
17.
18.
For what is believed to be the first time, a three-dimensional tungsten photonic crystal is demonstrated to emit light effectively at wavelength lambda = 1.5 microm. At a bias of V = 7 V, the thermal emission exhibits a full width at half-maximum of delta lambda = 0.85 microm. Within this narrow band, the emitted optical power is 4.5 W and the electrical-to-optical conversion efficiency is approximately 22% per emitting surface. This unique emission is made possible by a large, absolute bandgap in the infrared lambda and flat photonic dispersion near the band edges and in a narrow absorption band. 相似文献
19.
Modification of spontaneous emission rate of micrometer-sized light sources using hollow-core photonic crystal fibers
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We investigate numerically and experimentally the modification of
the spontaneous emission rate for micrometer-sized light sources
embedded in a hollow-core photonic crystal fiber (HCPCF). The
diameter of the light source is deliberately chosen such that they
could be easily introduced into the central hole of the hollow-core
photonic crystal fiber by capillary force. The photoluminescence
from the microparticles is measured by using an inverted microscope
in combination with a spectrometer. The modification of the spontaneous
emission rate is observed in a wavelength region where there is no
band gap. The experimental observations are consistent with
the simulation results obtained by the plane wave expansion and
finite-difference time-domain techniques. 相似文献
20.
提出了一种具有宽绝对禁带的一维磁性光子晶体结构,该结构由相同的折射率和物理厚度以及不同的波阻抗的两种磁性材料交替组合而成.通过传输矩阵法分析可得,相比于非磁性光子晶体,该光子晶体的禁带对入射角和偏振都不敏感,从而具有更宽的绝对禁带.合适地调节两种磁性材料的参数,增加两者波阻抗的差值,该光子晶体的绝对禁带宽度也相应地增加;调节两种磁性材料的物理厚度,其绝对禁带中心也会随之调整;最后,将两个满足上述条件的一维磁性光子晶体组成异质结构,其第一禁带宽度与禁带中心之间的比值可达到1.41以上. 相似文献