Analysis of the Bloch mode spectra of surface polaritonic crystals in the weak and strong coupling regimes: grating-enhanced transmission at oblique incidence and suppression of SPP radiative losses

The Bloch mode spectrum of surface plasmon polaritons (SPPs) on a finite thickness metal film has been analyzed in the regimes of weak and strong coupling between SPP modes on the opposite film interfaces. The SPP mode dispersion and associated field distributions have been studied. The results have been applied to the description of the light transmission through thick and thin periodically structured metal films at oblique incidence. In contrast to normal incidence, all SPP Bloch modes on a grating structure participate in the resonant photon tunnelling leading to the transmission enhancement. However, at the angle of incidence corresponding to the crossing of different symmetry film SPP …

Determination of the spatial extension of the surface-plasmon evanescent field of a silver film with a photon scanning tunneling microscope.

A photon scanning tunneling microscope is employed to probe the surface-plasmon field in the evanes- cent region of a silver film for p (parallel to the plane of incidence) and s (perpendicular to the plane of incidence) polarizations of the light beam at several angles of incidence near the critical angle. The in- teraction between the field and the probe is measured and compared to theoretical calculations involving a single four-media model. A systematic analysis of images obtained for several positions of the optical fiber above the film is presented and it is shown that, for tip-to-sample distances smaller than half the wavelength of the incoming light, the collected intensity curves a…

Étude en champ proche optique de cristaux photoniques bidimensionnels sur membrane suspendue

Nous presentons une etude experimentale en champ proche optique d'un cristal photonique 2D inscrit dans une membrane suspendue photoluminescente emettant a 1.5 μm. Les images obtenues mettent en evidence le guidage de la PL par la membrane, l'effet de bande interdite photonique ainsi que l'inhibition de l'emission de PL a l'interieur du cristal photonique.

Unguided plasmon-mode resonance in optically excited thin film: exact modal description of Kretschmann–Raether experiment

With the aim of studying electromagnetic surface wave resonance, we rigorously solve the homogeneous and inhomogeneous problem associated with an optically excited thin metallic film. We then demonstrate unambiguously that the excited eigenmode engendering plasmonic resonance in the so-called Kretschmann–Raether configuration is an unguided mode (i.e., with an anti-evanescent structure). This result, challenging the classical interpretation of the outgoing wave condition applied to surface waves, permits a quantitative interpretation of the attenuated total reflection curves.

Electronic momentum distribution in the one-dimensional extended Hubbard model: determinantal Monte Carlo study

Abstract The effect of electron–electron (e–e) interaction on trans -polyacetylene ( t -PA) properties is investigated within the framework of an extended Hubbard model in one dimension. For numerical calculation, we use the determinantal version of quantum Monte Carlo approach, which provides a breakthrough to simulate statistical fluctuations in the systems with many degrees of freedom, in order to obtain mean values for observables of physical interest. This allows one to analyze the discrete system of fermions without encountering the numerical instabilities that generally occur from the original problem involving anticommuting fermion operators. We calculate the electronic momentum dis…

Near-field probing of active photonic-crystal structures

We report a study of the optical near field of an active integrated component operating near the 1.55-mum telecommunications wavelength. The device is based on a two-dimensional photonic crystal etched in a suspended InP membrane. Topographic as well as optical information is collected by use of a scanning near-field optical microscope in collection mode, providing information about the local distribution of the losses.

Numerical study of photolithography system: electromagnetic differential method

The R-matrix propagation algorithm is incorporated into the differential method to achieve an extended capability for modelling a photolithography systems. We show throughout this work the ability of the R-matrix algorithm and differential method to analyse gratings of arbitrary depth, profile, and conductivity without encountering numerical instabilities. We calculate the field intensity and the transmitted amplitudes in the 0 and −1 orders below different masks. We study also the influence of the various parameters (incidence, groove spacing, groove depth and index of refraction) on the field intensity maps and the transmittivity power. These results agree with the experimental patent: we…

Ridge-enhanced optical transmission through a continuous metal film

Optical transmission through a continuous (without holes) metal film with a periodic structure of metal or dielectric ridges on one or both interfaces was numerically studied. The dependencies of the transmission on the ridge width and height as well as the ridge arrangements on the opposite interfaces were investigated in weak- and strong-coupling regimes. The transmission enhancement was shown to depend on the relative position of the ridge gratings on the opposite interfaces of a film, confirming the role of resonant tunneling processes involving states of the surface polariton Bloch modes.

Photon Scanning Tunneling Microscopy and Reflection Scanning Microscopy

The Photon Scanning Tunneling Microscope (PSTM) is the photon analogue to the Electron Scanning Tunneling Microscope (ESTM). It uses the evanescent field due to the total internal reflection (TIR) of a light beam in a prism modulated by a sample attached to the prism. The exponential decay of the evanescent field is characterized by the penetration depth dp and depends on the angle of incidence θ, the wavelength and polarization of the incident beam. Changes in intensity are monitored by a probe tip scanned over the surface, and the data are processed to generate an image of the sample. Images produced by a prototype instrument are shown to have a vertical resolution of about 3 A and a late…

First images obtained in the near infrared spectrum with the photon scanning tunneling microscope

Abstract First images obtained in the near infrared spectrum with a photon scanning tunneling microscope are presented. The intensity of the light collected by the fibertip, at λ = 1.3 λm , which is a function of the separation between the tip and the sample surface is in agreement with that predicted by the theory. Images of quartz and silicon oxide are presented and the latter is compared with that obtained by an atomic force microscope.

Local excitation of surface plasmon polaritons at discontinuities of a metal film: Theoretical analysis and optical near-field measurements

Nonresonant excitation of surface plasmon polaritons at discontinuities of a gold film is numerically studied and experimentally observed with scanning near-field optical microscopy. It is shown that surface polaritons can be effectively launched at the edges of a metal film illuminated at an angle of incidence greater than the resonant angle of surface polariton excitation. The electromagnetic near-field distribution over a thin metal film exhibits significantly different features under resonant and nonresonant excitations due to different surface polariton excitation mechanisms. In the latter case the field distribution is determined by the interference of the excitation light and surface…

Numerical simulations of photon scanning tunneling microscopy: role of a probe tip geometry in image formation

Abstract Numerical simulations of two-dimensional probe–object system emulating a photon scanning tunnelling microscope are presented. R -matrix propagation algorithm incorporated into the differential method was used to achieve an extended capability to rigorously model a realistic system consisting of both a probe and a sample. Influence of the probe tip parameters on image formation in scanning near-field microscopy has been investigated. Coupling of the near-field to a single-mode probe and formation of a guided fundamental mode in a probe were investigated for various probe widths and lengths. The influence of the probe taper shape and apex size on near-field images was studied for sin…

Numerical study on localized defect modes in two-dimensional lattices: a high Q-resonant cavity

Abstract The spectral widths and the quality factors of defect modes localized for different defects structures formed in a 2D photonic crystal composed of a square lattice of circular rods of indium antimonide (InSb) are theoretically investigated. It is first shown that some factors such as the lattice nature, the line defect orientation, the nature and the defect width have a significant influence on the optical properties of the studied structures and can improve the Q factor and defect peak transmission intensity. Particularly, the transmission spectra of the defects calculated by means the transfer-matrix-method for a particular structure of eight line defects introduced in its center…

The behavior of correlation functions in trans-polyacetylene: quantum Monte Carlo study

We present results of a quantum Monte Carlo simulation of the one-dimensional half-filled Hubbard model to study different correlation functions in the trans-polyacetylene (t-PA) polymer. Magnetic structure of the model in t-PA is studied for a different range values of the Hubbard repulsion interactions, U and V ,w here U 4t , with V ∈[ U/2 ,U ] (t is the hopping matrix elements). In this work, we investigate the behavior of the magnetic correlation functions for different phases transitions between different ordering (antiferromagnetic and ferromagnetic) by varying the nearest-neighbor interactions U and V between different atomic sites. Our results indicate that there is a presence of a …

Resolution of the photon scanning tunneling microscope: influence of physical parameters

Abstract The photon scanning tunneling microscope (PSTM) is the photon analogue of the electron scanning tunneling microscope (ESTM). It uses the evanescent field due to total internal reflection (TIR) of a light beam in a prism modulated by a sample placed on the base of the prism. Our experimental results shown details which present a lateral size as small as 200 A. The PSTM axial resolution is more difficult to evaluate. It is a function of the roughness of the sample. For very smooth samples, images shown an axial resolution of about 10 A. At last we discuss how both lateral and axial resolution can be affected by several parameters such as the tip surface distance and the roughness of …

Real space observation of two-dimensional Bloch wave interferences in a negative index photonic crystal cavity

We report here the direct observation of two-dimensional (2D) Bloch wave interferences in a negative index photonic crystal by using optical near-field microscopy techniques. The photonic crystal is formed by a defectless honeycomb lattice of air holes etched in III-V semiconductor slab. A scanning near-field optical microscope is used to visualize spatially, as well as spectrally, the light distribution inside the photonic crystal. The recorded near-field spectra and maps presented here unambiguously demonstrate the Bloch wave interferences within the photonic crystal. Then, the spectral and spatial evolution of these interferences allows us to recover experimentally the 2D band diagram of…

From Measurement to Control of Electromagnetic Waves using a Near‐field Scanning Optical Microscope

An Evanescent Field Optical Microscope

We present a new form of optical microscope. An evanescent field is produced in the lower index medium of an ATR system and modulated by a sample deposited on the hypotenuse of the prism. A sharpened fiber optic probes this field and gives information about the topography of the surface.

Applications of near-field optics to the characterization of optoelectronics components

In the race towards purely optical communications, the necessity of producing integrated components is linked to the requirement for the precise characteriza-tion of optoelectronic components. Near-field detection techniques meet this requirement, AFM (Atomic Force Microscopy), for instance, can provide the topography of a given sample. In conjunction with these new tools, several different kinds of near-field optical microscopes (NFOM) have appeared. They enable the characteriza-tion of the components with a resolution better than that imposed by the Rayleigh criterion. This is primarily due to the fact that they are sensitive to the evanescent waves. This document presents several areas r…

Quantum Monte-Carlo calculation of correlation functions of undistorted, cis-distorted and trans-distorted polyacene

Abstract We have studied polyacene within the Hubbard model to explore the effect of electrons correlations on the bond–bond correlation as well as spin–spin correlation functions. We employ the determinantal quantum Monte-Carlo to resolve the microscopic Hamiltonian of this system which involves a nearest-neighbor electron hopping matrix element t , an on-site Coulomb repulsion U . The objective of this study is to understand the effect of electron–electron (e–e) correlations on the structural instability in polyacene. We find strong similarities between polyacene and polyacetylene. The system shows no tendency to destroy the imposed bond-alternation pattern. The spin–spin correlations sho…

Theoretical study of an absorbing sample in infrared near-field spectromicroscopy

Abstract This paper is devoted to study the near-field spectrometry in the infrared spectral range. To understand the behavior of the infrared light diffracted by an object, numerical calculations have been carried out with Fourier Modale (FM) method within R-matrix algorithm. We consider the case of three-dimensional system including a translational symmetry in one direction, where is included an homogenous layer in which is buried an absorbing object. Using an optical near-field analysis and by calculating the electric field intensity distribution, both of the thickness effect and the lateral size of the absorbing sample are investigated. It is found that the distribution of the intensity…

How light gets through periodically nanostructured metal films: a role of surface polaritonic crystals

The physical origin of the enhanced optical transmission of periodically structured films related to surface plasmon polaritons is discussed from first principles. The enhancement of transmission through smooth, randomly rough and periodically nanostructured films is considered. Analysis shows that any metal (or dielectric) nanostructured film can exhibit enhanced transmission in certain spectral ranges corresponding to surface plasmon (or phonon) polariton Bloch mode states on a periodic structure. Resonant tunnelling via these states is responsible for the transmission enhancement. The properties of surface polaritonic crystals are analogous to those of photonic crystals and can find nume…

Imaging of test quartz gratings with a photon scanning tunneling microscope Experiment and theory

We use the differential formalism of the electromagnetic theory of gratings to interpret the images of test sinusoidal or lamellar quartz gratings obtained with a photon scanning tunneling microscope. The period of the grating is 0.5 μm, and the height of the rule is 0.2 μm. It is shown that the images depend strongly on several parameters, such as polarization or angle of incidence, with respect to the ruling direction. A systematic study of the isointensity lines above the gratings as a function of polarization is presented, and it is shown that the image contrast can be increased or decreased depending on the sample–probe distance. To model the interaction of the fiber probe with the ele…

Discontinuity induced angular distribution of photon plasmon coupling

Metal-dielectric transitions are important structures that can display a host of optical characteristics including excitation of plasmons. Metal-dielectric discontinuities can furthermore support plasmon excitation without a severe condition on the incident angle of the exciting photons. Using a semi-infinite thin gold film, we study surface plasmon (SP) excitation and the associated electromagnetic near-field distribution by recording the resulting plasmon interference patterns. In particular, we measure interference periods involving SPs at the scanable metal/air interface and the buried metal/glass one. Supported by optical near-field simulations and experiments, we demonstrate that the …

Non-Linear Optical Properties of Hybridized Surface Plasmon Polaritonic Crystals: Observation of Optical Bistability

Summary form only given. The use of surface plasmons (SP) is recognized as being central to the development of nanoscale assemblies of photonic and opto-electronic devices. This is motivated by the spatially confined nature of these electromagnetic waves as well as their resonant behavior. Amongst plasmonic supporting structures, surface plasmonic crystals (SPCs) draw particular interest because of their tailored optical properties. A geometry common to SPCs consists in a periodic arrangement of holes or slits in a metal film. Their complex optical response is then governed by coherent interactions between Bloch modes at the film's interfaces and modes supported by the holes or slits. These…

Computation of near field diffraction by a dielectric grating: a comparison with experiments

We use an eigenmode method to compute the near field diffracted by one-dimensional dielectric gratings. We present a set of easily programmable recurrence relations that give the diffracted field from the incident one. The numerical results are compared with the experimental images obtained with the Photon Scanning Tunneling Microscope (PSTM).

Recent Experimental Results with the PSTM: - Observation of a Step on a Quartz Surface. - Spatial Spectroscopy of Microwaveguides

The Photon Scanning Tunneling Microscope (PSTM) is based on the frustration of the total internal reflected beam by the end of an optical fiber. Till today it has been used to obtain topographic information generally for smooth samples. In this paper we report two different kinds of experimental results. First, when the sample is in the form of a step, our measurements demonstrate how the images, obtained in the constant intensity mode, depend on the orientation of the incident beam of light with respect to the step. Next, we show that the first derivative of the collected intensity with respect to the probe-sample distance at each point of the sample yields to a new kind of image named her…

Sample–tip coupling efficiencies of the photon-scanning tunneling microscope

The photon-scanning tunneling microscope is the photon analog to the electron-scanning tunneling microscope. It uses the evanescent field due to the total internal reflection of a light beam in a prism, modulated by a sample attached to the prism. The exponential decay of the evanescent field is characterized by the penetration depth dp and depends on the angle of incidence θ, the wavelength, and the polarization of the incident beam. The 1/e decay lengths range from 150 to 265 nm as deduced from the expression of the electric-field intensity in the rarer medium for θ = π/2. If we place another optically transparent medium near the surface, frustrated total reflection occurs. It is shown th…

Photonic band gaps in highly ionic medium: CuCl, CuBr, CuI

Abstract Using the transfer-matrix-method, we have studied the propagation of electromagnetic waves through two-dimensional (2D) and three-dimensional (3D) dispersive photonic band gap (PBG) structures constructed from copper halides materials, especially from CuCl compounds. A special attention has been paid to the effect of the polariton gap on the PBG properties. This study reveals that “Twin gaps” and “Twin brothers” concepts and the flattened bands phenomena in both polarizations and for both structures (i.e. 2D and 3D) are all consequences of the strong photon–phonon coupling, particularly near the long wave length transverse optical phonon frequency. Furthermore, results for comparis…

Quantum Monte Carlo study of the alternating extended Peierls–Hubbard model applied to the trans-polyacetylene

Abstract The one-dimensional alternating Peierls–Hubbard model is especially interesting as nontrivial model for conjugated polymer chains, such as polyacetylene. We study this model for chains of 64 sites using the determinantal method based on Hubbard–Stratonovich transformation. We obtain the first electronic energies and their mean fluctuations at half-filling as a function of the on-site electron–electron interaction (both short and long range U, V coupling are considered). We also study the effect of the electron–electron interaction on the dimerization by investigating some of the important correlation functions, such as spin–spin correlation, on-site charge and the specific heat. Th…

Near-Field Distribution of Optical Transmission of Periodic Subwavelength Holes in a Metal Film

Recent experimental discovery of the enhanced optical transmission through metal films with periodic subwavelength holes has given rise to a considerable interest in the optical properties of such structures due to their possible numerous applications in optics and optoelectronics as well as rich physics behind the phenomenon of the transmission enhancement [1–4]. The transmission of a subwavelength aperture is very low and proportional to the fourth power of the ratio of its diameter and light wavelength. However, if a metal film is perforated with a periodic array of such holes, the optical transmission can be significantly enhanced [1]. Being normalized to the total area of the illuminat…

Analysis of image formation with a photon scanning tunneling microscope

International audience; The photon scanning tunneling microscope (PSTM) is based on the frustration of a total internal reflected beam by the end of an optical fiber. Until now it has been used to obtain topographic information, generally for smooth samples. We report theoretical as well as experimental results on the observation of a step on a quartz substrate with the PSTM. These results demonstrate the effects on image formation of the distance between the fiber tip and the sample surface, the orientation of the incident beam with respect to the step, the polarization, and the coherence of the light. Good agreement exists between numerical simulations and experiments. We show that a pert…