The general objective of this presentation is to demonstrate the great potential of two dimensional (2D) Photonic Crystals (PC) based on InP-membranes bonded onto silica on silicon substrates, with a special emphasis on the development of various classes of 2D PC microlasers. The basic building block consists in an InP (and related material) membrane including a 2D PC formed by a lattice of holes : the membrane is bonded onto low index material,e.g. silica on silicon substrate, in the prospect of heterogeneous integration with silicon based microelectronics. Examples of devices will be presented, specifically micro-lasers based on 2D PC micro-cavities as well as on 2D in plane and surface emitting Bloch modes (2D Distributed-Feed-Back micro-laser).

We investigate the effect of fabrication tolerances on the propagation losses of light guided in photonic crystal waveguides. We focus on slab photonic crystals defined as a regular array of holes in high index material such as silicon. The deviation of photonic crystal lattice parameters, such as the hole diameter, from the ideal results in the shift of the guided mode in the photonic band gap. This shift occurs randomly along a photonic waveguide as the electromagnetic wave propagates in it. Because the range of frequencies supported in a photonic crystal waveguide is typically very narrow, even a small deviation of the lattice parameters may result in a sufficiently large shift for the wave to fall out of the guided range and become lossy. Indeed, we demonstrate that a deviation in hole size as small as a few percent can result in a guided mode becoming radiative. Consequently, a wave propagating in a real photonic crystal waveguide undergoes multiple transitions between guided and radiative modes, depending on the local variations of the photonic crystal parameters. This results in lossy propagation of the wave. We present simulations of the light propagation in a photonic crystal waveguide incorporating real-life fabrication tolerances.

The silicon-silicondioxide system is used to illustrate the effect of interaction between a photonic gap in a periodic structure and a polaritonic gap originating from one of the constituent materials. Si is a near ideal dielectric material in the infrared region with a high refractive index and modest dispersion for λ>4 μm. Amorphous SiO₂ has lattice absorption in the infrared, with a strong Reststrahlen band covering the wavelengths 8-9.3 μm. Optical multilayer calculations of reflectance spectra for Si/SiO₂ double- and multilayers have been made. The results illustrate the effect of the metal-like optical properties of SiO₂ in the Reststrahlen region. The high reflectance band persists in thin double layers and combines with conventional interference in the dielectric Si-film. From conventional optical coating technology it is known since long that a dielectric coating can be used to broaden and strengthen a Reststrahlen band, but this has not previously been applied to photonic crystals. For the experimental part, the Si/SiO₂-system was prepared using standard microelectronic fabrication technology. Polycrystalline Si (poly-Si) and amorphous SiO₂ (a-SiO₂) were both deposited by CVD processes. Si from silane, and SiO₂ from decomposition of tetra-ethoxy-silane (TEOS). a-SiO₂ is also grown by wet- and dry oxidation of a Si wafer. The calculated and the measured reflectance spectra for Si/SiO₂ double-layers are compared, and the overall agreement is very satisfactory. In particular, we can observe the Reststrahlen band of high reflectance and the interaction between this material stop band and the designed stop band, defined by the layer thicknesses.

In this paper we discuss the design and implementation of integrated planar optical devices realized by exploiting the unique dispersion properties of photonic crystal (PhC) devices. In particular, we demonstrate the ability to focus and spatially route optical beams in the absence of channelized structures. By this we mean that these devices do not contain any form of lateral confinement, in the sense of a physical structure, other than the dispersion properties of the crystal lattice. To this end, lateral control is imposed on the propagating wave by virtue of engineering the band structure of the photonic crystal lattice. Our approach to this effort is based on engineering the dispersion diagram of a given periodic structure outside of its band gap. As such, this allows for the determination of unique propagation characteristics and corresponding devices, as we show in theoretical simulations and experimental results.

An accurate three-dimensional method to calculate the Bloch modes of photonic crystal waveguides is proposed. Good agreement with available experimental and numerical data is obtained. The originality of the method lies in the fact that the Bloch modes are seen as the electromagnetic fields associated to the complex poles of an in-plane transversal scattering matrix. In comparison with previous approaches, the computational domain discretized is smaller and a higher accuracy for the losses of photonic crystal waveguides is achieved.

It is common to assume that, for small wavenumbers, the phase and group velocities of a propagating wave in a photonic crystal coincide. This is the consequence of a simple mathematical fact: if the frequency is an analytic function of the small wavenumber, it must depend only on its magnitude but not on its direction. We have found an important exception to this rule: if a mode is doubly-degenerate for the vanishing wavenumber (at the Γ-point of the photonic dispersion curve), it can be strongly anisotropic even for small wavenumbers. The anisotropy can be so strong that, for certain propagation directions, the group velocity may oppose the phase velocity. For the other propagation directions the group and phase velocities may be co-linear. The unusual band structure of the extremely anisotropic photonic crystal results in counter-intuitive refractive properties, such as the total internal reflection for small incidence angles. Whether such extreme anisotropy is manifested is determined by the symmetry of the photonic crystal. Analytic theory based on group-theoretical considerations and the supporting results of the finite element electromagnetic simulation are presented, and several potential applications listed.

By surface-relief structures optical functions like anti-reflection, light trapping or light distribution and re-direction can be realized. New applications in solar energy systems and in displays require structures with sub-micron features which are homogeneously distributed over large areas. This paper addresses the design and the whole experimental process chain from the micro structure origination on large areas to the replication and the system integration in the specific application. Topics are antireflective surfaces for solar systems and displays, light trapping in polymer solar cells, sun protection systems for facades and diffusers for projection displays and in glazing. For the micro structure origination we investigated the suitability of holographic recording in photoresist by using a large scale interferometer. An argon ion laser was used as a coherent light source at a wavelength of 364nm. With the interferometer set-up periodic and stochastic interference patterns were recorded in positive photoresist. In the case of periodic structures, grating periods between 200nm and 20µm have been realized. By carefully modeling resulting resist profiles it was possible to originate even prismatic surface-relief profiles. Structures with good homogeneity were originated on areas of up to 4800 cm² by optimizing the interferometer set-up and the photoresist processing.

We propose an optical switch of a guided-mode resonant grating (GMRG) filter with a Kerr medium and simulate optical switching effects by using the nonlinear finite differential time domain (FDTD) method. It is shown that the nonlinear FDTD method is needed for simulating the optical switch effect by analyzing the bistable feature. The doubly periodic structure was used in order to produce the optical Kerr effect efficiently. Because a doubly periodic GMRG filter operates for small beam diameter and grating area, the electric field can be accumulated to the small area. The doubly periodic grating consisted of materials with refractive indices of 1.88 and 1.0, and the material of index 1.88 had a third-order susceptibility of 8.5×10^-10esu. The TE polarized plane waves were normally incident on the grating structure as “pump light” and “probe light.” When the intensity of “pump light” increases, the refractive index changes due to the optical Kerr effect, so that the resonant condition of the GMRG filter for the “probe light” also changes. Therefore the transmittance of “probe light” can be controlled by the “pump light.” By changing “pump light” from 0 to 100kW/mm², the transmittance of “probe light” was controllable from 0 to 0.6.

A diffraction-grating based demultiplexer is made to have low polarization dependence and high diffraction efficiency properties. The device is made is made of a Si grism working in reflection and having optimised grove profile easily manufactured by standard crystallographic etch of Si surface.

We have proposed a new structure of guided-mode resonant grating (GMRG) filter with low sideband reflectance. This GMRG filter consists of a high refractive index thin-film on an antireflection structured (ARS) surface called “moth-eye structure”. This antireflective GMRG filter is valid for reducing reflection of nonresonant light waves in a wide spectral range. This antireflective GMRG filter is valid for reducing reflection of nonresonant light waves in a wide spectral range. The resonant reflection of this new filter was investigated by numerical calculation based on an electromagnetic grating analysis. In the case of an antireflective GMRG filter with aspect ratio 2, the sideband reflectance for nonresonant light waves was lower than 0.5% for TM polarized light in the wide-wavelength range. We have fabricated an antireflective GMRG filter. The triangular grating of fused silica for ARS surface was fabricated by reactive ion etching due to high-density fluorocarbon plasma with resist line patterns and chromium thin-film line patterns as etching masks. The fabricated antireflective GMRG filter was a period of 333 nm and a height of about 666 nm. The thickness of a TiO₂ thin-film deposited on the triangular grating was about 100 nm. Resonant peak was detected at wavelength of 680 nm, and peak intensity was 45%. Moreover, it was found that sideband reflectance was less than 4%.

We present recent applications of one-dimensional (1D) and two-dimensional (2D) periodic structures. The structures were designed using rigorous diffraction theory and produced by modern micromachining techniques (electron beam writing, optical lithography). In addition, interferometric recording of periodic structures was investigated in order to fabricate periodic structures with arbitrary profile shapes.

Blazed-binary optical elements are diffractive components, composed of subwavelength ridges, pillars or other simple geometries carefully etched in a dielectric film, that mimic standard blazed-echelette diffractive elements. Recent experimental results in the visible showed that, blazed-binary optical elements offer high diffraction efficiencies and unique properties that cannot be achieved by standard echelette diffractive elements. Meanwhile, the manufacture of these optical elements for operation in the visible represents a challenge for today’s technologies since they involve both sub-micron sizes and high aspect ratios. In this paper, we extend the study to the thermal infrared, where the fabrication constraints are compatible with simple manufacture process such as photolithography. A 3λ-period blazed-binary grating etched into a silicon substrate, implementing an antireflection function (zinc sulphide deposition over the etched structure), was designed for operation under TM polarization at 10.6 μm. Its fabrication involved contact photolithography, reactive ion etching and an evaporation deposition over the etched structure. A first-order transmitted diffraction efficiency of 80 % was measured under TM polarization at 10.6 μm. This result validates the use photolithography, a low-cost technology, and an antireflection deposition, for the manufacture of efficient blazed-binary diffractive elements operating for thermal imaging (8-12μm infrared band).

Today’s technologies available for the fabrication of micro structured optical elements are well developed for defined classes of structures. Techniques for very complex optical functions or for combinations of optical functions together with others are more or less in the level of research or labs. A promising approach for complex grating fabrication is the use of optical near field holography (NFH) and e-beam writing for unification of the advantages. The paper wants to show the potential of both techniques itself as well as the potential that arises from their teamwork. The paper demonstrates one and two dimensional gratings, chirped and unidirectional gratings fabricated by NFH using e-beam written masks. It shows also possibilities for the fabrication of gratings on binary, multilevel and continuous optical profiles.

The paper deals with diffraction on high reflecting surfaces with periodically modulated dielectric properties. Period of the structure is supposed to be close to the wavelength multiplied by an integer and, consequently, for close-to-normal incidence of a p-polarized wave there exists the resonance (Wood anomaly) caused by simultaneous excitation of two surface plasmon polaritons (SPP). We present the analytical solution of the problem using the surface impedance as the small parameter that enables us to consider variety of metals and semiconductors in red and infrared regions. The simple explicit solution obtained makes it possible to present the results in a closed analytical form and examine them in detail for arbitrary grating form. We present the dependence of the polariton, specular and other reflected waves phases and amplitudes on the angle of incidence, wavelength, and on the grating period and form. We derive the universal self-similar representation of the solution in the close resonance vicinity. This enables us to carry out a thorough investigation of the strong resonance peculiarities fine structure. There are formulated conditions on the grating parameters that correspond to the specific redistribution of the radiation flux between outgoing waves and the SPPS. In particular, we demonstrate that in spite of the geometric symmetry, excitation of one of the polaritons can be suppressed totally. The total suppression of any subset of the outgoing diffracted waves is also possible, and a variety of other energy redistributions between them is possible as well. The results are of interest both from theoretical point of view and in view of a wide field of possible applications for the novel optic and opto-electronic problems concerning light transformation and control.

The interaction between the two kinds of gaps that appear in the band structure of a photonic crystal has been studied. The structure gap appears as a consequence of diffraction in the periodic structure, if the optical contrast between the the two matrials is sufficiently strong. The width of such gaps increases with the optical contrast and the position, for a given structure, scales with the lattice constant. Secondly, the dielectric function of one of the materials may be such that the photonic crystal exhibits an effective stop band. Metals have a dielectric function with a large negative real part in the visible and infrared wavelength regions. Metallo-dielectric photonic crystals have been intensively studied recently, and interesting results have been obtained. Alternatively, a Reststrahlen band can be used, within which the dielectric function is metal-like. The physical mechanism behind such a band is the excitation of polaritons, i.e. lattice oscillations. Only compounds have Reststrahlen bands, and they appear in the infrared. We refer to the corresponding stopband as a polaritonic gap. Transfer matrix calculations have been used to obtain the photonic bandstructure in the infrared for a 2-D square structure consisting of beryllium oxide cylinders in air. Photonic band structure calculations across a reststrahlen band region are numerically demanding because of the strong dispersion. Calculations were made with different lattice constants and fill factors. We have compared a situation when the two gaps are widely separated, with one where the gaps are close or even on top of each other. We report two kinds of forbidden gap states as a function of the imaginary wave-vector. We use normal incidence transmittance spectra to define phonomenological gaps, and report their variation with linear density and lattice constant.

The recently developed fast Fourier factorization used in differential theory of gratings is extended to nonlinear optics in order to be applied to nonlinear Kerr media. The main difficulty presented by the nonlinear equations arise from the existence of discontinuous products of discontinuous functions for which no rule of factorization can be applied. Our method avoids factorization of such type of products. Computations show the good convergence and lack of Gibbs phenomenon of the numerical results when the method is applied to deep gratings illuminated in TM polarization with grooves made of nonlinear material.

Analytical examination of plane electromagnetic wave diffraction on a surface with periodically modulated impedance or a shallow profile is presented. For small absorption and high reflection there exist sharp resonances caused by excitation of surface plasmon polaritons. We consider the specific angles of incidence for in-plane geometry corresponding to simultaneous excitation of two polaritons propagating in the opposite directions. The simplest case corresponds to close-to-the-value arcsin(1/3) angle of incidence, when two diffracted orders with numbers +1 and -2 are close to the surface polaritons simultaneously and their amplitudes in the vicinity of the resonance become much greater than that of the incident wave. Scattering both of the resonance waves on the grating leads to essential changes in the amplitudes of the specular and other reflected waves, including the anti-specular reflected wave, as compared with nonresonance case for rather small the surface impedance modulation. Dependence of the amplitudes of the reflected waves and the polaritons on the parameters of the problem is examined for the arbitrary-form gratings. The characteristic values of the most relevant “inter-resonance” and “resonance” Fourier amplitudes of the grating (relating to the first-order interaction of the polaritons and to transformation of the incident wave into the polaritons, respectively) are found. It is shown that in the resonance vicinity, the results can be simplified. This allows complete analytical treatment. Existence of the wide set of the gratings that correspond to the universal self-similar behavior under double resonance conditions is demonstrated. The gratings with specific parameters relating to the given redistribution of the energy between different reflected waves and polaritons are described. A comparison between the evolved theory and the experimental results shows excellent agreement. The results obtained may be employed to smart media design.

This contribution concentrates on studying diffraction characteristics in optical diffraction gratings. As modeling tools, both rigorous and approximate approaches have been analyzed and/or modified and successfully implemented. As for the diffraction characteristics, a general background is briefly presented, i.e. an idea of characterization of mechanisms and diffraction processes, classification of diffraction characteristics and regions with typical diffraction regimes. Different types of synchronisms as the parametrical dependences of the diffraction efficiency on the two of important parameters are discussed. Parameters chosen can either be of a grating or a mount type, thus defining different areas of applicability. A special role is devoted to the volume phase synchronism, i.e. a parametrical dependence of the efficiency on the relative structure period and relative structure/modulation depth. Then, extending the previous studies, description of the two types of grating classes, namely metallic and volume planar (holographic), based on the simulations, is given. Last part of the paper is devoted to new synchronism studies within resonant regions, namely to guided-mode resonance effect (reflection case). Apart from volume phase synchronism, parametrical dependences of the diffraction efficiency with respect to wavelength-duty cycle, wavelength-angle of incidence, wavelength-relief depth, wavelength-grating period, wavelength-polarization angle are given; the case of the conical mount is also discussed.

The chirping of a pulse propagating on a nonlinear media is nowadays a rather well studied phenomena and we are aware that requires an appreciable propagation length to develop. A nonlinear stack of finite dimension, does not have those dimensions. Therefore, chirping in this media is a rather new feature that deserves to be studied at considerable length given the greater importance that those structures have in photonics. We present a nonlinear analysis of a finite stack, nonlinear at each media and compare it with its analytically solvable linear case. The pulse propagation is discussed, in particular we demonstrate intensity dependence of the chirp as a distinctive nonlinear signature. We show two additional nonlinear characteristics: the nonlinear switching and the bistability.

Variational methods are applied to the design of a two-dimensional lossless photonic crystal slab to optimize resonant scattering phenomena. The method is based on varying properties of the transmission coefficient that are connected to resonant behavior. Numerical studies are based on boundary-integral methods for crystals consisting of multiple scatterers. We present an example in which we modify a photonic crystal consisting of an array of dielectric rods in air so that a weak transmission anomaly is transformed into a sharp resonance.

The Liquid Crystalline Blue Phases (LC BPs) and their diffraction patterns were investigated experimentally and theoretically. We stabilized Blue Phases and measured their diffraction pattern for different wavelengths of monochromatic light with the help of a conoscopic setup of a polarization microscope. Moreover, the diffraction patterns were calculated with the help of a 4x4 matrix method which allows amplitude and phase investigations.

On the basis of the partial coherence theory, a uniform formulation for the self-imaging is established, which can be used for both continuous and temporal illuminations with any kind of spectra. The formulation includes the cross mutual spectral density, the time diffractive intensity distribution and the averaged diffractive intensity distribution of grating at the self-imaging distances, and the last two variables are deduced in terms of the cross mutual spectral density. The self-imaging effect of different illuminations is then studied with a numerical stimulation, such as the continuous illumination with a polychromatic light source, and the ultra-short laser pulses with or without frequency chirp. It is interesting to find that the ultra-short pulse laser illumination and the polychromatic continuous illumination have the similar average intensity distribution of self-imaging, so that the self-imaging effect may be helpful for the study of the temporal and spectral characteristics of ultra-short laser pulses. An experiment with a polychromatic continuous light illumination (LED) is given, the results are the same as the predicted.

Comparing with thin film filters and arrayed waveguide gratings, holographic gratings can realize the highest channel capacity, the lowest insertion loss, etc., which are desirable for DWDM applications. In this paper, we have calculated the diffraction efficiencies of grating structures, such as rectangular, sinusoidal and symmetric triangular gratings with the technique of the rigorous coupled-wave analysis. The presumed conditions, such as TE- and TM- polarization, the aspect ratio of holographic gratings, have been investigated. It is shown that our results are in good agreement with other previous works. Further, we’ve established an experimental setup for fabricating the planar binary holographic gratings. The gratings we’ve made have a relatively high groove or line density (e.g., 600,900 and 1200 lines/mm), and they’ve achieved high angular dispersion between each individual wavelength in their first diffraction order with relatively high transmitted diffraction efficiencies (e.g., for the 600 lines/mm grating, the efficiency is near 65%), which are able to demultiplex 1.31μm and 1.55μm wavelengths in CWDM (coarse wavelength division multiplexing). The fabricated high-density gratings should have important applications for DWDM in the near future.

The study of steady states for picosecond dissipative optical solitons, appearing in single-mode semiconductor laser structures multilayered in a direction of passing those pulses, is developed. Such solitons are shaped due to resculpturing some external optical pulses because of the passive mode-locking process in traveling-wave regime. The relations between the pulse parameters and structure properties are chosen in such a way that the process is incoherent in behavior and provides the phase decay of incoming pulses. The analysis performed demonstrates that both dark and bright optical solitons can be supported by the structures with a quasi-linear gain and a fast relaxing saturable absorption.

We trapped and manipulated the micro-particles by two beam interference. The micro-particles were pulled toward the bright fringe and were aligned along the periodic interference pattern. We observed the distribution of trapped particles at the various polarization configurations by adjusting the polarization states and measured the optical force acting on the particles. The particles were trapped in bright fringe by intensity gradient in the case of parallel polarization state. In the case of perpendicular polarization state, the particles aligned along periodic pattern even though there was no intensity modulation. Consequently, the results showed that the optical force can be generated from not only the intensity modulation but also no intensity modulation.