Fabrication and characterization of three-dimensional metallodielectric photonic crystals for infrared spectral region

We propose a technique for the realization of three-dimensional metallodielectric photonic crystals based on fabricating polymeric structures using the interference lithography followed by the magnetron deposition of a gold nanolayer. The infrared reflectance spectra of the fabricated photonic crystals are studied. The spectrometry and finite-difference time-domain modeling data show that there is a photonic band gap centered at the wavelength approximately equal to the photonic crystal period.     

Transmission Spectra and Optical Properties of a Mesoporous Photonic Crystal Based on Anodic Aluminum Oxide

Optical properties of a one-dimensional photonic-crystal film with a lattice period of ≈380 nm formed by electrochemical etching of an aluminum foil are investigated. Experimental data on the spectra of transmission and reflection in the region of the first, second, and third stop bands of anodic photonic crystal of aluminum oxide are compared with a theoretical dependence obtained from the well-known dispersion relation. The possibility of creating selective narrow-band optical filters based on mesoporous one-dimensional photonic crystals is analyzed. The conditions of enhancement of an electromagnetic field of laser radiation at 532 nm under normal incidence on a photonic-crystal surface are established. The possibility of generation of optical harmonics under the conditions of sharp increase in the effective field of the driving radiation in a mesoporous photonic crystal of anodic aluminum oxide filled with lithium iodate is analyzed.     

Li-impurity effect in optical spectra of KTaO<Subscript>3</Subscript>:Er<Superscript>3+</Superscript> crystals

The optical properties of one-dimensional photonic crystals based on porous anodic aluminum oxide films have been studied by measuring transmittance and specular reflectance spectra in the visible and UV spectral regions. Angular dependences of the spectral positions of optical stop bands are obtained. It is shown that the reflectance within the first stop band varies from point to point on the sample surface, reaching a level of 98–99% at some points. The dispersion relation for electromagnetic waves in the model of infinite periodic structure is calculated for the samples under study. The possibility of using models with an infinite or finite number of layers to calculate reflectance spectra near the first optical stop band is discussed.     

Modeling of the optical properties of porous silicon photonic crystals in the visible spectral range

Optical devices based on photonic crystals are of great interest because they can be efficiently used in laser physics and biosensing. Photonic crystals allow one to control the propagation of electromagnetic waves and to change the emission characteristics of luminophores embedded into photonic structures. One of the most interesting materials for developing one-dimensional photonic crystals is porous silicon. However, an important problem in application of this material is the control of the refractive index of layers by changing their porosity, as well as the refractive index dispersion. In addition, it is important to have the possibility of modeling the optical properties of structures to choose precisely select the fabrication parameters and produce one-dimensional photonic crystals with prescribed properties. In order to solve these problems, we used a mathematical model based on the transfer matrix method, using the Bruggeman model, and on the dispersion of silicon refractive index. We fabricated microcavities by electrochemical etching of silicon, with parameters determined by the proposed model, and measured their reflection spectra. The calculated results showed good agreement with experimental data. The model proposed allowed us to achieve a microcavity Q-factor of 160 in the visible region.     

Optical properties of one-dimensional photonic crystals obtained by micromatchining silicon (a review)

The theoretical and experimental investigations of photonic band gaps in one-dimensional photonic crystals created by micromatchining silicon, which have been performed by the author as part of his doctoral dissertation, are presented. The most important result of the work is the development of a method of modeling photonic crystals based on photonic band gap maps plotted in structure–property coordinates, which can be used with any optical materials and in any region of electromagnetic radiation, and also for nonperiodic structures. This method made it possible to realize the targeted control of the optical contrast of photonic crystals and to predict the optical properties of optical heterostructures and three-component and composite photonic crystals. The theoretical findings were experimentally implemented using methods of micromatchining silicon, which can be incorporated into modern technological lines for the production of microchips. In the IR spectra of a designed and a fabricated optical heterostructure (a composite photonic crystal), extended bands with high reflectivities were obtained. In a Si-based three-component photonic crystal, broad transmission bands and photonic band gaps in the middle IR region have been predicted and experimentally demonstrated for the first time. Si–liquid crystal periodic structures with electric-field tunable photonic band-gap edges have been investigated. The one-dimensional photonic crystals developed based on micromatchining silicon can serve as a basis for creating components of optical processors, as well as highly sensitive chemical and biological sensors in a wide region of the IR spectrum (from 1 to 20 μm) for lab-on-a-chip applications.     

Fermi-edge polaritons in Bragg multiple-quantum-well structures

The polariton propagation in one-dimensional photonic crystals and quasicrystals based on highly doped quantum-well structures has been theoretically studied. The superradiant and photonic crystal regimes have been considered and expressions for band gap edges for light waves in the Bragg structures have been obtained. The reflection and absorption spectra of such systems have been calculated and the so-called two-wave approximation to their study has been applied. The optical properties of the doped multiple-quantum-well structures are compared with those of undoped ones.     

Photoreflectance Spectroscopy of Porous Silicon Photonic Crystals

Journal of Russian Laser Research - We study one-dimensional porous silicon photonic crystals by photoreflectance (PR) spectroscopy. We calculate the reflectance and PR spectra by transfer matrix...     

一维光子晶体禁带的展宽

作为一维光子晶体的应用基础，一维光子晶体的禁带是研究的重点。通过传输矩阵的方法分析了一维光子晶体禁带的特性，讨论了影响带宽的因素。说明了相对带宽对光子晶体设计的重要性。在这个基础上讨论了扩展一维光子晶体带宽的方法，提出了在角域范围内对光子晶体进行叠加的方法，为设计制造一维光子晶体提供了一种行之有效的方法。分别对2个、3个和4个晶体的叠加进行了分析，最后计算了所设计的合成晶体的反射率。其中4个晶体的叠加，相对带宽达到57．52％，极大地展宽了一维光子晶体的禁带，从而证明利用角域的叠加来展宽一维光子晶体的禁带是非常有效的。     

含负折射率材料的一维光子晶体的光学传输特性

采用光学传输矩阵方法,模拟研究了由正折射率材料和负折射率材料交替组成的一维光子晶体的光学传输特性.计算了这种含负折射率材料的一维光子晶体的透射谱和色散关系.结果表明,在正入射时,含负折射率材料的光子晶体的带隙要比传统的光子晶体要大得多,并具有狭窄的透射带,从光学薄膜理论的色散关系出发解释了形成上述现象的原因.讨论了在不同的偏振模式下,光以中心波长入射时,反射率随着入射角度的变化关系.发现含负折射率材料的一维光子晶体具有更好的角度特性,可以用来实现对中心波长的全方位反射.     

Electronic-Excitation Energy Transfer between Dye Molecules Adsorbed in One-Dimensional Photonic Crystals

Electronic-excitation energy transfer between molecules of Coumarin 7 (donor) and Rhodamine B (acceptor) have been experimentally investigated in one-dimensional photonic crystals based on oxidized mesoporous silicon and in a similar matrix, which does not possess the properties of a photonic crystal. The efficiencies of excitation transfer between donor and acceptor molecules have been determined based on the donor-fluorescence quenching and sensitized acceptor luminescence. It is established that the efficiency of electronic-excitation energy transfer in a photonic crystal increases in comparison with that for porous silicon.     

基于光子晶体塔姆态的带隙分裂

将由两个一维介质层光子晶体组成的异质结拓展为超晶格结构,分析了该结构的能带和透射谱。该超晶格结构可以产生多个界面隧穿态,它们之间的耦合可产生新的通带。研究结果表明,该通带的宽度随光子晶体的周期数变化,而通带的中心位置保持不变。当光子晶体周期数取特定值时,这个通带将发生分裂,在带间产生零相位带隙或π相位带隙。     

组合一维光子晶体全能反射器

为了能充分地展宽一维光子晶体的全方位禁带,从一维光子晶体禁带结构的特点出发,对于不发生Brewster效应的一维光子晶体,提出了通过两个或两个以上一维光子晶体的组合来实现和展宽一维光子晶体全方位禁带的理论依据和最佳组合方式.并给出了所提出的组合方式下相关参数的定量计算公式. 最后用传输矩阵法进行了数值模拟计算,对提出的组合方式进行验证,计算结果与预期结论符合很好.     

外磁场作用下一维光子晶体的光传输特性

采用光学传输矩阵方法,研究了外磁场作用下一维光子晶体的光传输特性.在外磁场作用下,介质介电函数在回旋频率ω.附近受到强烈的调制,使组分材料的色散关系发生明显改变,导致光子晶体的能带发生变化,透射谱出现复杂结构.在光子带隙中出现窄通带,窄带中的光是局域的.这表明,在不改变光子晶体组分材料的条件下,可以通过改变外磁场的大小,调制光子晶体的能带及其光传输性质.     

Temperature dependence of the parameters of stop bands of globular photonic crystals

The results of the experimental study of the characteristics of stop bands of globular photonic crystals are presented depending of the globule diameter, temperature, and the presence of a dielectric medium in pores between globules. The reflectance spectra of the (111) surface of a globular photonic crystal are analyzed using a fiber-optic technique. As the sample temperature is lowered, the reflectance maximum shifts to the long-wavelength spectral region. The spectral characteristics of stop bands are compared with calculations based on the Wolf-Bragg formula.     

含各向异性左手材料一维光子晶体的传输特性分析

采用光学传输矩阵方法,研究了由各向异性左、右手材料交替排列构成的一维人工周期结构的带隙结构和传输特性,讨论了反射率随入射角度的变化关系。结果表明,含各向异性左手材料的光子晶体比传统的光子晶体有更宽的禁带;含各向异性左手材料的一维光予晶体具有更好的角度特性,可以用来实现对某一低频波段的全方位反射;通过适当选取左手材料的参数,禁带中会出现狭窄的透射峰。     

Computing for second harmonic generation in one-dimensional nonlinear photonic crystals

A numerical study of second harmonic generation (SHG) in one-dimensional nonlinear photonic crystals based on full nonlinear system of equations, implemented by a combination of the method of finite elements and fixed-point iterations, is reported. This model is derived from a nonlinear system of Maxwell’s equations, which partly overcomes the known shortcoming of some existing models relied on the undepleted-pump approximation. We derive a general solution of SHG in one-dimensional nonlinear photonic crystals structures. The convergence of our method is fast. Numerical simulations also show the conversion efficiency of SHG can be significantly enhanced when the frequencies of the fundamental wave are located at the photonic band edges or are assigned to the designed defect states.     

Extending the zero-effective-phase photonic bandgap by one-dimensional ternary photonic crystals

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.     

Accurate calculation of reflectance spectra for thick one-dimensional inhomogeneous optical structures and media: stable propagation matrix method

Numerical instability is usually observed when the propagation matrix method is used to calculate the reflectance and transmittance spectra for the thick one-dimensional inhomogeneous optical structures and media. To remove this numerical instability we applied two procedures, the normalization and the singular-value decomposition, for the propagation matrix and the matrix involved in calculating the matrix of reflection coefficients, respectively. Examples of a cholesteric liquid crystal and a helical structure of ferroelectric liquid crystals with a twist defect show that the modified propagation matrix method is able to accurately calculate the reflectance spectra for thick structures.     

一维光子晶体的反射率特性

基于平面波展开法,设计九层一维光子晶体结构,通过改变结构中介质层的厚度,运用MATLAB编程计算一维光子晶体反射率特性,厚度差值变小时,不存在反射波的区域将增加变大。研究结果为一维光子晶体器件的设计提供理论参考。     

Description and reconstruction of one-dimensional photonic crystal by digital signal processing theory

A method of describing one-dimensional photonic crystals(1DPCs) based on Z-domain digital signal processing theory is presented. The analytical expression of the target band gap spectrum in the digital domain is obtained by the autocorrelation of its impulse response. The feasibility of this method is verified by reconstructing two simple 1DPC structures with a target photonic band gap obtained by the traditional transfer matrix method. This method provides an effective approach to function-guided designs of interference-based band gap structures for photonic applications.