共查询到20条相似文献,搜索用时 156 毫秒
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光子晶体的禁带特性为伪装材料的光谱控制研究提供了一条新的技术途径。利用传输矩阵的方法建立了一维光子晶体光谱透射、反射的理论模型,针对伪装材料近红外高反射、中远红外低发射的要求,优选Ag,MgF2和ZnS等材料作为光子晶体的薄膜材料,采用真空蒸发镀膜的方法制备出Ag/MgF2,Ag/MgF2/ZnS 4种不同周期结构的一维光子晶体,并实验研究了一维光子晶体的光谱反射和透过特性。结果表明:材料和周期结构对一维光子晶体光谱特性有不同的影响,通过优化设计可以实现在伪装波段内的光谱特性要求。 相似文献
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一维三元异质结构光子晶体反射特性 总被引:1,自引:0,他引:1
利用传输矩阵法对一维三元光子晶体异质结构的光学特性进行了研究,讨论了介质层厚无序度对三元结构光子禁带的影响.研究表明,将具有相互交叠光子禁带的一维光子晶体叠加构成异质结,可以有效地增大全角度反射的频率范围,当入射角从0°增大到89°,该结构均可实现从0.410 w/w0到0.654 w/w0宽频波段的全反射;相对于二元结构,三元结构可以减小在实际制作过程中随机误差引起的介质层厚无序对光子带隙的影响.该研究结果可为实现可见光及红外光波段大角度反射器的制备及应用提供理论支持. 相似文献
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本文基于Bragg反射光栅是一维光子晶体的一种特例结构, 提出利用一维光子晶体理论进行Bragg衍射光栅的设计并对其性能进行研究分析. 根据一维光子晶体理论, 建立了罗兰圆结构的凹面椭圆Bragg蚀刻衍射光栅, 研究了TE/TM模式下器件的分光特性以及入射角度改变对器件角色散造成的影响; 同时, 文中对比了空气介质型和金属铝线型椭圆Bragg蚀刻衍射光栅的光学性能. 研究结果表明: 选择合适的器件参数, 可以实现TE/TM模式下1.465-1.615 μm范围内波长衍射效率在95% 以上, 且空气介质型结构光栅的通道均匀性要优于金属铝线型结构光栅; 入射角在30°-60°范围内变化时, 相同入射角度下, TM模式下器件角色散大于TE模式. 基于Bragg衍射光栅设计的波分复用器是一种尺寸小、衍射效率高的新型EDG 波分复用器, 为未来密集型EDG波分复用器发展提供了一种新的设计思路. 相似文献
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与介质光子晶体相比,金属光子晶体的带隙特性在毫米波和亚毫米波波段有着重要的应用价值.基于Yee网格的频域有限差分法推导得出的本征模方程,求解后能方便而又可靠地得出介质光子晶体的带隙图和场分布.但由于金属与介质的本质差异,该方法不能直接应用于金属光子晶体.文中引入了金属表面边界条件,推导了二维金属周期结构的光子带隙本征模方程.通过数值计算,得出了不同晶格结构(正方/三角格子)下两种模式(TE/TM)的全禁带特性,并与介质周期结构的禁带特性进行对比,分析了金属周期结构在模式选择和器件集成方面的优点.
关键词:
金属光子晶体
频域有限差分法
全禁带 相似文献
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研究了具有异质结构且适用于3~5μm红外光区的一维光子晶体高反射镜,系统地分析了光波在一维周期性光子晶体中的反射特性,通过传输矩阵计算和仿真验证了λ/4介质膜系的反射率和最佳禁带宽度。在此基础上,选取Si和Y_2O_3两种材料,构造了24层一维光子晶体的双异质结构,仿真结果表明:在3~5μm红外波段,该结构的反射率为97.418%~99.999%。为了减少膜层数量,以金属银为衬底,设计了以Si和Y_2O_3为介质层结构的一维金属增强型光子晶体,其总层数为9层,仿真结果表明:在3~5μm红外波段,其反射率为98.943%~99.979%。 相似文献
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与介质光子晶体相比,金属光子晶体的带隙特性在毫米波和亚毫米波波段有着重要的应用价值.基于Yee网格的频域有限差分法推导得出的本征模方程,求解后能方便而又可靠地得出介质光子晶体的带隙图和场分布.但由于金属与介质的本质差异,该方法不能直接应用于金属光子晶体.文中引入了金属表面边界条件,推导了二维金属周期结构的光子带隙本征模方程.通过数值计算,得出了不同晶格结构(正方/三角格子)下两种模式(TE/TM)的全禁带特性,并与介质周期结构的禁带特性进行对比,分析了金属周期结构在模式选择和器件集成方面的优点. 相似文献
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Design and optimization of a SiC thermal emitter/absorber composed of periodic microstructures based on a non-linear method 下载免费PDF全文
《中国物理 B》2015,(9)
Spectral and directional control of thermal emission based on excitation of confined electromagnetic resonant modes paves a viable way for the design and construction of microscale thermal emitters/absorbers. In this paper, we present numerical simulation results of the thermal radiative properties of a silicon carbide(Si C) thermal emitter/absorber composed of periodic microstructures. We illustrate different electromagnetic resonant modes which can be excited with the structure,such as surface phonon polaritons, magnetic polaritons and photonic crystal modes, and the process of radiation spectrum optimization based on a non-linear optimization algorithm. We show that the spectral and directional control of thermal emission/absorption can be efficiently achieved by adjusting the geometrical parameters of the structure. Moreover, the optimized spectrum is insensitive to 3% dimension modification. 相似文献
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基于特殊的SiC周期性结构,理论分析了SiC表面特殊电磁模态的激发特性,并利用数值模拟的方法研究了该周期性结构的红外辐射/吸收特性。模拟结果表明该周期性结构在电磁波照射下可以支持多种电磁模态的激发,并且多种电磁模态之间存在相互耦合现象,证实了理论分析的结果。基于非线性优化算法,分别对结构在单个频率整个角度范围内的红外辐射/吸收特性,以及整个研究频段内的垂直方向红外辐射/吸收特性进行了优化。优化的结果显示,相比于原来的结构,优化后结构的等效发射率/吸收率有较显著地提升。 相似文献
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星载多波段红外光学系统的杂散辐射分析 总被引:2,自引:0,他引:2
引入反向蒙特卡罗法与双向蒙特卡罗法对红外光学系统的杂散辐射进行分析,基于光谱辐射传递因子导出了焦平面辐射能流计算式.以某星载多波段红外光学系统为例,在检验计算可靠性的基础上,模拟了各波段辐射能从地球背景和光机内壁面到焦平面的传播过程,分析了壁面吸收率与温度的影响.结果表明,采用双向蒙特卡罗法可有效地模拟辐射能从地球向星载光学系统焦平面的传播过程,采用反向蒙特卡罗法可容易地分析光机内部热辐射的影响;光机内壁面吸收率对视场外杂散辐射的传播有很大影响,温度高于250 K的光机内壁面热辐射成为主要的杂散光源. 相似文献
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《Physics letters. A》2020,384(34):126877
Based on the diffraction effect of sub-wavelength dielectric grating and the optical property of periodic photonic crystal, a hybrid structure of sub-wavelength grating all-dielectric multilayer thin film containing periodic photonic crystal is proposed. The transmission property of the structure is simulated by finite element method (FEM). The result shows that the discrete state generated by the sub-wavelength waveguide grating will be coupled with the continuous state generated by the photonic crystal cavity and the Fano resonance can be formed. The Fano resonance sensing model based on structural parameters and resonance wavelength are established, the influence of structural parameters on the Fano resonance spectral curve is quantitatively analyzed by numerical simulations, and the dynamic detection of the refractive index of samples is realized. The above structure can realize the optical refractive index sensing with high figure of merit (FOM) value and provide an effective theoretical reference for the formation of Fano resonance in the all-dielectric hybrid structure. 相似文献
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V. V. Rumyantsev S. S. Podlipaev 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(6):653-656
The generation of photon polaritons by a field of a moving ?? particle is numerically simulated. These polaritons are localized in a crystal nanofilm with a diamondlike structure. Expressions for the spectral density of the radiation excited by the field of a charged particle in a quasi-two-dimensional film are deduced. 相似文献
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Rong Huang Donald H. Bilderback Kenneth Finkelstein 《Journal of synchrotron radiation》2014,21(2):366-375
Cornell energy‐recovery linac (ERL) beamlines will have higher power density and higher fractional coherence than those available at third‐generation sources; therefore the capability of a monochromator for ERL beamlines has to be studied. A cryogenic Si monochromator is considered in this paper because the perfect atomic structure of Si crystal is needed to deliver highly coherent radiation. Since neither the total heat load nor the power density alone can determine the severity of crystal deformation, a metric called modified linear power density is used to gauge the thermal deformation. For all ERL undulator beamlines, crystal thermal deformation profiles are simulated using the finite‐element analysis tool ANSYS, and wavefront propagations are simulated using Synchrotron Radiation Workshop. It is concluded that cryogenic Si monochromators will be suitable for ERL beamlines in general. 相似文献
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V. B. Voloshinov G. A. Knyazev L. A. Kulakova N. Gupta 《Physics of Wave Phenomena》2013,21(2):134-138
The control over the parameters of the far-infrared and terahertz radiation by the acoustooptic method is discussed. The operation of a tunable acousto-optic filter based on the tellurium crystal is investigated. The crystal used in the filter was transparent for the optic radiation in the wavelength range of 4.0 to 23 µm. The device allows electronic tuning and processing of optic images in the spectral interval of 8.0 to 14 µm. 相似文献
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A small-size optical interleaver based on directional coupler in a 2D photonic crystal slab with triangular lattice of air holes is designed and theoretically simulated using plane wave expansion and finite-difference time-domain method. The interleaver is formed by two parallel and identical photonic crystal slab waveguides which are separated by three rows of air holes. The coupling region is designed below the light line to avoid vertical radiation. The simulated results show that the coupling coefficient is increased and the final length of the interleaver is decreased by enlarging the radius of the middle row of air holes. The transmission properties are analyzed after the interleaver’s structure is optimized, and around 100 GHz channel spacing can be got when the length of the interleaver is chosen as 40.5 μm. 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
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In this work, we have investigated the thermal radiation power spectra of 1D photonic crystal structure containing Si and SiO2 having an absorbing substrate with truncated thickness. The thermal radiation power spectra are determined by the means of a theoretical model based on a transfer matrix for both normal and oblique incidence together with Kirchhoff’s second law. It is observed that thermal radiation power spectra show strong dependence on truncation parameter and incident angle. 相似文献