Photonic crystals: basic concepts and devices

The art of microphotonics consists in confining photons, in one or more directions, in structures having dimensions about the wavelength, and doing this for the longest possible duration. The objective is then to associate these microstructures in order to carry out a photonic integration allowing data processing in very compact systems and using low optical powers. Photonic crystals have largely showed these last years their capacity to achieve these goals. To cite this article: P. Viktorovitch et al., C. R. Physique 8 (2007).     

Tunable structures and modulators for THz light

We review recent results of both experimental and theoretical work aimed at developing tunable devices with optical properties in the THz range controllable by an external parameter. The presented devices include a semiconductor platelet, strontium titanate based elements and one-dimensional photonic crystals with defects. We show that it is possible to strongly modulate the complex permittivity in the THz range by light illumination, temperature and voltage, and the experimental results obtained by time-domain terahertz spectroscopy are found to be in a very good agreement with theoretical calculations. The control by illumination or applied bias enable a very fast modulation of the THz waves which is useful for prospect applications e.g. in the domain of communications. To cite this article: P. Kužel, F. Kadlec, C. R. Physique 9 (2008).     

Les matériaux magnétiques hyperfréquences à l'ère des métamatériaux

This article investigates the advances brought by metamaterials in order to obtain attractive magnetic microwave properties. Can magnetic metamaterials outperform conventional soft magnetic materials? In the case where permeability levels and bandwidth are the key figures of merit, it is acknowledged that copper-based metamaterials can exceed the performance of soft magnetic materials, but only at operating frequencies above 10 GHz. As for low frequency operation, magnetic metamaterials may also be preferred to conventional magnetic materials when requirements include excellent temperature stability or immunity to external magnetic fields. However, in many cases, metamaterials need to include certain conventional magnetic constituents in order to compete with conventional magnetic materials. Several types of metamaterials containing conventional magnetic inclusions and well suited for industrial production are presented. Last but not least, it is underlined that the investigations on metamaterials are beneficial to scientific exchanges between scientists from different areas. To cite this article: O. Acher, C. R. Physique 10 (2009).     

Unipolar photonic memristive-like nonlinear switching in split-ring resonator based metamaterials

Photonic memristor, which performs the function as memristor working on electromagnetic fields, can accelerate the development of all-optical network. A unipolar photonic memristive-like switching behavior in split-ring resonator based metamaterials was reported. Transmission-power (T-P) loops are observed in the metamaterials. And the T-P loops change with the detect frequency which indicates the tunability and designability of the photonic memristor. These behaviors are attributed to the increasing dielectric constant of MgTiO₃ ceramic caused by the interaction of sample and electromagnet field. The mechanism supplies a general foundation for photonic memristors which can be used from radio frequency to optical wavelength.     

Photonic dispersions of semiconductor-quantum-dot-array-based photonic crystals in primitive and face-centered cubic lattices

We study the energy dispersions of photonic crystals based on the semiconductor-quantum-dot arrays. It has been shown that for the most commonly used semiconductor materials, and as compared with the primitive cubic lattice, the photonic crystal in a face-centered cubic (fcc) lattice exhibits a very promising energy dispersion relationship with an overall photonic bandgap. The bandgap is most prominent along the Λ(Γ–L) line inq space. The results explain the difficulties in fabricating photonic crystals in fcc lattices. They explain also the experimental works of Vlasov et al. [Physical Review B55, R13357–13360 (1997)], where it has been demonstrated that for CdS nanocrystals embedded in fcc porous silica matrices the photonic bandgaps are observed for any direction of the radiation incidence, being most pronounced for the [111] direction.     

Effect of anisotropy on the photonic band gap and surface polaritons of a one-dimensional single-negative photonic crystal

The effect of anisotropy on the photonic band structure and surface polaritons of a one-dimensional photonic crystal made of uniaxially anisotropic epsilon-negative (ε<0,μ>0) and mu-negative (ε>0,μ<0) metamaterials is theoretically investigated. Two different cases of uniaxially anisotropic epsilon-negative and mu-negative metamaterials are considered. It is found out that for one case of anisotropy, one-dimensional photonic crystal does not have any single-negative band gap. As a result, it can not support the surface polaritons. While, for another case, the structure shows single-negative band gaps. So, the surface polaritons can be excited at the interface of such a photonic crystal. However, these surface polaritons, unlike the isotropic case, are not omnidirectional and they are restricted to a limited rang of the propagation constant.     

Transmission properties of Fibonacci quasi-periodic one-dimensional photonic crystals containing indefinite metamaterials

The transmission properties of Fibonacci quasi-periodic one-dimensional photonic crystals (1DPCs) containing indefinite metamaterials are theoretically studied. It is found that 1DPCs can possess an omnidirectional zero average index (zero-n?) gap which exists in all Fibonacci sequences. In contrast to Bragg gaps, such zero-n? gap is less sensitive to the incidence angle, the scale length and the polarizations of electromagnetic waves. When an impurity is introduced, a defect mode appears inside the zero-n? gap with a very weak dependence on the incidence angle and scaling.     

Slowing down the light for delay lines implementation: Design and performance

Optical delay lines are key building blocks for all-optical signal processing. Photonic crystal structures can demonstrate efficient group velocity reduction, together with a wide-bandwidth and reduced high-order group velocity dispersion. Theses structures also offer the ability for 2D integration within photonic integrated circuits. This paper presents the performances of photonic crystal structures engineered for slowing down the light, and discuss the actual limitation encountered due to fabrication imperfections. To cite this article: A. Talneau, C. R. Physique 10 (2009).     

含特异材料一维超导光子晶体的带隙特性研究

利用传输矩阵法研究了含特异材料的一维超导光子晶体的带隙特性. 研究表明, 这类超导光子晶体同样具有由传统的电介质材料构成的超导光子晶体一样的低频带隙, 且在一定的参数下该低频带隙可以相当宽. 但在一定的结构参数下, 这类超导光子晶体同完全由传统的电介质构成的光子晶体一样不存在低频带隙. 还就超导光子晶体的偏振特性、光子晶体结构参数及环境温度的变化对光子带隙结构的影响进行了研究. 关键词： 超导光子晶体 传输矩阵法 特异材料 光子带隙     

激光全息光刻技术在微纳光子结构制备中的应用进展

微纳光子结构研究随着光子学、半导体物理学及微加工技术的发展而逐渐蓬勃开展,并在其结构、理论、制备技术等方面取得了系列进展。受限于目前的微加工技术水平,要成功制备大尺度、高质量的光子材料仍然存在着一定挑战。激光全息光刻技术作为一种简便快捷的微结构制作技术已经发展成为一种经济快速制作大面积微纳超材料及光子晶体模板的重要手段。介绍了激光全息光刻技术的原理,详细阐述了该技术在制作三维面心立方、木堆积结构、金刚石结构光子晶体以及光学周期类准晶、手性超材料、周期性缺陷结构等微纳光子结构中的应用研究进展。激光全息光刻技术成功制作微纳光子结构为光子材料在更多领域的广泛应用提供了基础和方法。     

Nanostructural effects on optical properties of tungsten inverse opal

Tungsten (W) photonic crystals are very attractive because of their potential applications in the conventional lighting field. In this work we show that W nanostructures have dominative effects on optical properties of W inverse opal. The nanoparticle structure of W phase can cause intensive optical absorption and breakdown of the photonic band gap; on the contrary, W inverse opal made from bulk and compact W phase would have weak absorption and possess a good photonic band gap. The results will throw a new light on the study and application of W photonic crystals and development of other photonic crystal and black-body materials. Electronic Supplementary Material  The online version of this article () contains supplementary material, which is available to authorized users.     

Metamaterials and infra-red applications

We review the electromagnetic properties of metamaterials aimed at operating at infra-red wavelengths, keeping their potential applications in mind. Split ring resonators and periodically loaded transmission lines are considered with the main emphasis on the guide lines, design rules and characterization techniques. In this context, we address the various routes towards pushing up the operating frequency in the mid- and near- infrared region, with special attention on the breaking of scaling rules and on the technological challenges for metal and full dielectric approaches. To cite this article: D. Lippens, C. R. Physique 9 (2008).     

Phonon propagation through photonic crystals—media with spatially modulated acoustic properties

The thermal conductivity κ of photonic crystals differing in degree of optical homogeneity (single crystals of synthetic opals) was measured in the 4.2–300 K temperature range. The thermal conductivity revealed, in addition to the conventional decrease in comparison with solid amorphous SiO₂ characteristic of porous solids, a noticeable decrease for T<20 K, the range wherein the phonon wavelength in amorphous SiO₂ approaches the diameters of the contact areas between the opal spheres. This effect is enhanced in the case of phonon propagation along the SiO₂ sphere chains (six directions in the cubic opal lattice). The propagation of light waves (photons) through a medium with spatially modulated optical properties (photonic crystals) is presently well studied. The propagation of acoustic waves through a medium with spatially modulated acoustic properties (phononic crystals) may also reveal specific effects, which are discussed in this paper; among them are, e.g., the ballistic mode of phonon propagation and waveguide effects.     

Analysis of photonic band gap structure for the design of photonic devices

A detailed analysis, based on Kronig–Penney model and finite-difference time-domain (FDTD) method, is used to explain the air-filling factor effect on the optical properties of defect-free photonic crystals. By the use of the Kronig–Penney model, we calculated the photonic band structure for electromagnetic waves in a structure consisting of a periodic square array of dielectric rods of lattice constant a separated by air holes. Gaps in the resulting band structures are found for waves of both polarisations. We analysed the air-filling factor effect on both polarisations in low and high frequency regions. It is shown that the frequency of the lower TE (transverse-electric) band edge is independent of the air-filling factor in the low frequency region. The opposite behaviour holds for the upper band edge, growing rapidly with the air-filling factor. Using the FDTD we simulated the electric field as the pulse propagates through the structure. The results of both approaches are compared, and the operation characteristics of the measuring air-filling factor device are described. We investigate the optical properties of a single and two defects incorporated in the PC, which can be potentially applied to ultra small surface-emitting-type channel drop filter. It is shown that the frequency and polarisation of the dropped light can be controlled by changing the size and/or shape of the defect. The electric field distribution calculations show that the electric field for a given frequency is located only at the defect, which means that each defect can detect only its corresponding wavelength. To cite this article: F. Ouerghi et al., C. R. Physique 5 (2004).     

Two-dimensional plasmonic metamaterials

The fabrication of three-dimensional photonic metamaterials faces numerous technological challenges. Many new concepts and ideas in the optics of metamaterials may be more easily tested in two spatial dimensions using the planar optics of surface plasmon polaritons. In this paper we review recent progress in this direction. Two-dimensional photonic crystals exhibiting either positive or negative refraction, and strongly anisotropic metamaterials, etc, are demonstrated and used in novel microscopy and waveguiding schemes. PACS 73.20.Mf; 42.70.-a     

Cavity QED effects with single quantum dots

A single quantum dot embedded in a photonic crystal defect cavity allows for the investigation of cavity quantum electrodynamics effects in a solid-state environment. We present experiments demonstrating the quantum nature of this fundamental system in the strong coupling regime. Photon correlation measurements are used to characterize the fundamental properties of this unique system: through these experiments, we identify an unexpected, efficient sustaining mechanism that ensures strong cavity emission and is quantum correlated with the exciton resonance, even when all the quantum dot resonances are far detuned from the cavity mode. To cite this article: A. Badolato et al., C. R. Physique 9 (2008).     

Temperature dependence of photonic crystals based on thermoresponsive magnetic fluids

The influence mechanisms of temperature on the band gap properties of the magnetic fluids based photonic crystals are elaborated. A method has been developed to obtain the temperature-dependent structure information (A_sol/A) from the existing experimental data and then two critical parameters, i.e. the structure ratio (d/a) and the refractive index contrast (Δn) of the magnetic fluids photonic crystals are deduced for band diagram calculations. The temperature-dependent band gaps are gained for z-even and z-odd modes. Band diagram calculations display that the mid frequencies and positions of the existing forbidden bands are not very sensitive to the temperature, while the number of the forbidden bands at certain strengths of magnetic field may change with the temperature variation. The results presented in this work give a guideline for designing the potential photonic devices based on the temperature characteristics of the magnetic fluids based photonic crystals and are helpful for improving their quality.     

Optical properties of metamaterial-based devices modulated by a liquid crystal

Due to the fact that it is possible to manipulate light with photonic crystals (PCs), PCs hold a great potential for designing new optical devices. There has been an increase in research on tuning the optical properties of PCs to design devices. We presented a numerical study of optical properties of metamaterial-based devices by liquid crystal infiltration. The plane wave expansion method and finite-difference time-domain method for both TE and TM modes revealed optical properties in photonic crystal structures in an air background for a square lattice. E7 type has been used as a nematic liquid crystal and SrTiO₃ as a ferroelectric material. We showed the possibility of the metamaterials for a two-dimensional photonic crystal cavity on a ferroelectric base infiltrated with a nematic liquid crystal.     

All-optical switch based on photonic crystal microcavity with multi-resonant modes

We present a design of all-optical switches based on one-dimensional photonic crystals (1D PhC) doped with nonlinear optical materials. The 1D PhC switch structure is composed of a PhC cavity sandwiched by two accessional PhC microcavities. The center PhC cavity has two resonant frequencies with nearly the same quality factors (Q), while the accessional PhC cavities have the same resonant frequency, which is equal to one of the resonant frequencies of the center cavity. The two accessional PhC cavities cause reduction of Q value in this resonant frequency and result in different Q values of two modes. We realize all-optical switch effect by selecting pump light wavelength at the low Q mode and probe light wavelength at the other mode. The theoretical simulations by using the finite difference time domain method show that the pump light intensity required to realize optical switch effect in the designed switch is 50 times smaller than that in one-dimensional photonic crystals cavity with only one resonant mode.