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The photodetachment of the [H.sup.-] ion in perpendicular electric and magnetic fields near a metal surface has been investigated on the basis of the semiclassical closed-orbit theory. Firstly, we give a clear physical picture of the detached electron's movement and find out the closed orbits of this system. Then we put forward an analytical formula for calculating the photodetachment cross section. It is found that the perpendicular electric and magnetic fields can produce some interesting effects. As the magnetic field is relatively weak, the influence of the electric field and the electrostatic potential dominates and the oscillatory structure in the photodetachment cross section exhibits a smoothly oscillating curve. As we keep the electric field and the ion-surface distance unchanged, with the increase of the magnetic field strength, the number of closed orbits is increased and the oscillatory structure in the photodetachment cross section is characterized by broad Landau level envelops. Therefore, we can use the perpendicular electric and magnetic fields to control the photodetachment of [H.sup.-] near a metal surface. Our study may guide future experimental research on the photodetachment microscopy of negative ion in external fields near surfaces. PACS Nos.: 32.80.Gc, 03.65.sq, 32.60.+i. Nous etudions le photo-detachement de l'ion [H.sup.-] dans des champs perpendiculaires electrique et magnetique pres d'une surface metallique sur la base de la theorie des orbites fermees semi-classiques. D'abord, nous donnons une image physique claire du mouvement de l'electron detache et trouvons les orbites fermees de ce systeme. Nous proposons alors une formule analytique pour calculer la section efficace de photo-detachement. Nous trouvons que les champs perpendiculaires electrique et magnetique peuvent produire des effets interessants. Comme le champ magnetique est relativement faible, l'influence du champ electrique et du potentiel electrostatique domine et la structure oscillante de la section efficace de photo-detachement montre une courbe oscillant doucement. Si nous gardons inchanges le champ electrique et la distance ion-surface, un accroissement du champ magnetique augmente le nombre d'orbites fermees et la structure oscillante de la section efficace de photo-detachement devient caracterisee par des enveloppes de niveaux de Landau elargis. Par consequent, nous pouvons utiliser les champs perpendiculaires electrique et magnetique pour controler le photo-detachement de [H.sup.-] pres d'une surface. Notre etude peut guider des experiences a venir sur la vision microscopique du photo-detachement d'ions negatifs pres des surfaces. [Traduit par la Redaction], 1. Introduction Over the last three decades, much attention has been paid to the study of the photodetachment of negative ions in external fields or near surfaces, both theoretically and [...]

We investigate the flow and heat transfer in nanofluids over a continuous variable thickness surface subjected to nonlinear velocity and thermal radiation. Three types of nanofluids, namely Cu, Ag, and [Al.sub.2][O.sub.3] were studied. A similarity transformation was used to obtain a system of nonlinear ordinary differential equations, which was solved numerically for general conditions. Numerical results were obtained for the skin friction, Nusselt number as well as for the velocity and temperature for selected values of the governing parameters, such as nanoparticle volume friction, surface thickness parameter, velocity power index parameter, and radiation parameter. A comparison of obtained numerical results is made with previously published results in some special cases, and found to be in a good agreement. PACS No.: 65.20.JK. Nous etudions l'ecoulement et le transfert de chaleur d'un nanofluide sur une surface d'epaisseur continuellement variable, sujet a des variations non lineaires de vitesse et a de la radiation thermique. Nous etudions trois types de nanofluide, Cu, Ag et [Al.sub.2][O.sub.3]. Une transformation de similarite nous fournit un systeme d'equations differentielles ordinaires non lineaires, que nous solutionnons numeriquement pour des conditions generales. Nos resultats incluent la friction superficielle, le nombre de Nusselt, ainsi que les profils de temperature et de vitesse pour des choix selectifs des parametres directeurs, comme la friction en volume des nanoparticules, les parametres d'epaisseur de surface, d'index de puissance de la vitesse et de radiation. Nous comparons nos resultats avec des resultats deja publies pour certains cas et trouvons un bon accord. [Traduit par la Redaction], 1. Introduction Boundary layer theory was presented in 1904 by Prandlt (see Schlichting [1]). The problem of boundary layer flow and heat transfer over a moving surface is of interest [...]

We derive a novel expression for the relativistic energy of electric and magnetic dipoles in an external electromagnetic field and discuss its implications. In particular, we find the relativistic dependence of the energy of a dipole on its velocity, v, and show that in the most convenient presentation of the energy (when the proper electric ([p.sub.0]) and magnetic ([m.sub.0]) dipole moments are involved, whereas the electric (E) and magnetic (B) fields are defined in the laboratory frame), its value essentially depends on the orientation of the velocity, v, with respect to vectors [p.sub.0], E, and [m.sub.0], B. To better understand the relativistic behavior of the energy of electric and magnetic dipoles, we introduce the notion of 'latent' momentum of an electric dipole, in addition to the known concept of 'hidden' momentum of a magnetic dipole. We finally show that the contribution of energy terms related to 'hidden' and 'latent' momenta of an electric or magnetic dipole is important in the relativistic case. PACS Nos.: 41.20.-q. Nous derivons une nouvelle expression pour l'energie relativiste d'un dipole electrique ou magnetique dans un champ electromagnetique externe et discutons ses consequences. En particulier, nous trouvons la dependance relativiste de l'energie du dipole sur sa vitesse v et montrons que dans le cas de la representation la plus appropriee de l'energie (quand les moments propres electrique ([p.sub.0]) et magnetique ([m.sub.0]) sont impliques, alors que les champs electrique (E) et magnetique (B) sont definis dans le referentiel du laboratoire), sa valeur depend essentiellement de l'orientation de la vitesse v par rapport aux vecteurs [p.sub.0], E et [m.sub.0], B. Afin de mieux comprendre le comportement relativiste de l'energie d'un dipole electrique ou magnetique, nous introduisons le concept d'impulsion latente du dipole electrique, en plus du concept mieux connu d'impulsion cachee du dipole magnetique. Nous montrons finalement que la contribution des termes d'energie relies aux impulsions latente et cachee des dipoles electrique ou magnetique est importante dans le cas relativiste. [Traduit par la Redaction], 1. Introduction In a series of recent publications [1-3], we derived novel expressions for the force, F, and torque, T, exerted on a compact electrically neutral bunch of charges, characterized [...]

When the electromagnetic potentials are expressed in the Coulomb gauge in terms of the electric and magnetic fields rather than the sources responsible for these fields they have a simple form that is nonlocal (i.e., the potentials depend on the fields at every point in space). It is this nonlocality of classical electrodynamics that is primarily responsible for the puzzle associated with the static Aharonov-Bohm effect: that its interference pattern is affected by fields in a region of space that the electron beam never enters. PACS Nos.: 03.50.De, 03.65.-w, 03.65.Vf, 03.75.-b. Lorsque les potentiels dans la jauge de Coulomb sont exprimes en fonction des champs electrique et magnetique, plutot qu'en fonction des sources responsables de ces champs, ils adoptent une forme simple qui est non locale, au sens ou le potentiel en un point depend des champs a chaque point de l'espace. C'est cette non localite de l'electrodynamique qui est avant tout responsable du puzzle associe a l'effet statique de Bohm-Aharonov : son patron d'interference est affecte par une region de l'espace que le faisceau d'electrons ne traverse jamais. [Traduit par la Redaction], 1. Introduction One of the most fascinating and still controversial issues in physics is the Aharonov-Bohm effect [1, 2] (see also refs. 3-10). The experimental arrangement needed to observe the [...]

We investigate the strain energy density of the spacetime continuum in the Elastodynamics of the Spacetime Continuum by applying continuum mechanical results to strained spacetime. The strain energy density is a scalar. We find that it is separated into two terms: the first one expresses the dilatation energy density (the 'mass' longitudinal term) while the second one expresses the distortion energy density (the 'massless' transverse term). The quadratic structure of the energy relation of Special Relativity is found to be present in the theory. In addition, we find that the kinetic energy pc is carried by the distortion part of the deformation, while the dilatation part carries only the rest-mass energy. The strain energy density of the electromagnetic energy-momentum stress tensor is calculated. The dilatation energy density (the rest-mass energy density of the photon) is found to be 0 as expected. The transverse distortion energy density is found to include a longitudinal electromagnetic energy flux term, from the Poynting vector, that is massless as it is due to distortion, not dilatation, of the spacetime continuum. However, because this energy flux is along the direction of propagation (i.e. longitudinal), it gives rise to the particle aspect of the electromagnetic field, the photon., 1 Introduction The Elastodynamics of the Spacetime Continuum (STCED) is based on the application of a continuum mechanical approach to the analysis of the spacetime continuum [1-3]. The applied stresses [...]

The gravitational field shielding by scalar field and type II superconductors are theoretically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polarization of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low temperature can be explained as the shielding of the Earth gravitational field by the Ginzburg-Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future., 1 Introduction Gravitation is one of the four fundamental interactions of nature. According to the Newtonian universal law of gravitation, any two objects in the universe attract each other with [...]

We study the interaction of electromagnetic waves with electrons. Our results can be applied to radio waves in the ionosphere or to lasers impinging on metals causing melting. We generalize the classical analysis of Zener to the case, which includes the interactions of the electrons with lattice vibrations or positive ions. We use the induced polarization to give a globally coherent and unifying analysis of the two cases: where collisions are important and where they are negligible. PACS Nos: 41.20.Jb, 52.35.Hr Nous etudions l'interaction d'ondes electromagnetiques avec des electrons. Nos resultats peuvent s'appliquer aux ondes radio dans l'ionosphere ou aux rayons lasers incidents sur des metaux et causant la fusion. Nous generalisons l'analyse classique de Zener au cas qui inclut l'interaction des electrons avec les vibrations du reseau ou les ions positifs. Nous utilisons la polarisation induite pour donner une analyse coherente et unificatrice des deux cas, lorsque les collisions sont importantes et lorsque elles ne le sont pas. [Traduit par la Redaction], Introduction Born and Wolf [1] in their famous book 'Optics' devoted a chapter to the 'optics of metals'. They discussed the subject exhaustively, explaining the Drude [2] theory of conductivity, [...]

We study the classical and quantum euclidean wormholes for an empty (4+1) dimensional Kaluza-Klein universe with a positive cosmological constant and a spatially flat Robertson-Walker type metric. It is shown that classical wormholes do not exist neither for the space-time sector nor the extra dimensional sector of this model, but two spectra of quantum wormholes as the solutions of the Wheeler-DeWitt equation exist that are consistent with the Hawking-Page conjecture about the necessary boundary conditions. In the spectrum where the external scale factor R shapes the quantum wormholes the internal scale factor a may play the role of effective matter source, and in the spectrum where the internal scale factor a shapes the quantum wormholes the external scale factor R may play the role of effective matter source. PACS Nos: 04.20.-q, 98.80.Qc Nous etudions les trous de ver euclidiens classiques et quantiques dans un univers de Kaluza-Klein vide a (4+1) dimensions, avec une constante cosmologique constante positive et une metrique spatialement plate de type RobertsonWalker. Nous montrons que les trous de ver classiques n'existent pas, ni dans le secteur spatio-temporel, ni dans le secteur extra-dimensionnel de ce modele. Par contre, deux spectres de trous de ver quantiques existent comme solutions de l'equation de Wheeler-DeWitt, qui sont coherents avec la conjecture de Hawking-Page sur la condition limite necessaire. Dans le spectre ou le facteur d'echelle exterieure R faconne les trous de ver quantiques, le facteur d'echelle interieure a peut jouer le role d'une source effective de matiere, alors que dans le spectre ou le facteur d'echelle interieure a faconne les trous de ver quantiques, le facteur d'echelle exterieure R peut jouer le role de source effective de matiere. [Traduit par la Redaction], 1. Introduction Classical euclidean wormholes are usually considered as euclidean metrics that consist of two asymptotically flat regions connected by a narrow throat (handle). Euclidean wormholes have been studied mainly [...]

Plane electromagnetic and gravitational waves interact with particles in such a way as to cause them to oscillate not only in the transverse direction but also along the direction of propagation. The electromagnetic case is usually shown by use of the Hamilton-Jacobi equation and the gravitational by a transformation to a local inertial frame. Here, the covariant Lorentz force equation and the second-order equation of geodesic deviation followed by the introduction of a local inertial frame are, respectively, used. It is often said that there is an analogy between the motion of charged particles in the field of an electromagnetic wave and the motion of test particles in the field of a gravitational wave. This analogy is examined and found to be rather limited. It is also shown that a simple special relativistic relation leads to an integral of the motion, characteristic of plane waves, which is satisfied in both cases. PACS Nos: 41.20Jb, 04.30-w Les ondes planes electromagnetiques et gravitationnelles interagissent avec les particules de facon a les faire osciller non seulement transversalement, mais aussi longitudinalement. Pour le demontrer dans le cas electromagnetique, nous utilisons habituellement l'equation de Hamilton-Jacobi. Dans le cas gravitationnel, c'est par une transformation vers un referentiel inertiel local. Ici, nous utilisons respectivement l'equation de force covariante de Lorentz et l'equation du deuxieme ordre de la deviation geodesique suivie par l'introduction d'un referentiel inertiel local. On entend souvent dire qu'il y a une analogie entre le mouvement d' une particule chargee dans le champ d' une onde electromagnetique et celui d' une particule test dans le champ d'une onde gravitationnelle. Nous examinons cette analogie et trouvons qu'elle est plutot faible. Nous trouvons aussi une relation relativiste simple, qui mene a une constante du mouvement caracteristique des ondes planes et qui est satisfaite dans les deux cas. [Traduit par la Redaction], Introduction It has been known for some time that the interaction of a plane electromagnetic wave with a test charge induces motion exclusive of that due to radiation pressure (for [...]

The movement of a two-level atom interacting with an electromagnetic wave while subject to gravity is studied using path-integral formalism. The propagator is first written in a standard form, lD(path) exp(i'/h)S(path), by replacing the spin with a unit vector aligned along the polar and azimuthal directions to determine the propagator exactly. Thus, the exact wave functions of the system are deduced. PACS Nos: 03.65.-w, 03.65.Ge, 03.65.Db A l'aide du formalisme de l'integrale de chemin, nous etudions le mouvement d'un atome a deux niveaux dans des champs electromagnetique et de gravite. Nous ecrivons d'abord le propagateur sous sa forme standard, lD(chemin) exp(i'/h)S(chemin), et nous le determinons exactement en remplacant le spin par un vecteur unite le long des directions polaire et azymutale. Nous en deduisons les fonctions d'onde exactes du systeme. [Traduit par la Redaction], 1. Introduction The applications of path-integral formalism have widely increased since a large class of potentials were resolved [1]. However, it is known that the most relativistic interactions are those [...]

The theoretical analyses in this paper show that a highly focused double-ring radially polarized Laguerre-Gaussian beam with a topological charge of 1 (R-[LG.sub.11]) can generate a small three-dimensional (3D) dark spot surrounded by an almost 100% uniform light shell in all directions. The cleanness and size of the 3D dark spot, the uniformity and strength of the light shell surrounding the dark spot, and the light efficiency all depend on the truncation parameter [beta] of the R-[LG.sub.11] beam and the numerical aperture (NA) of the system. When [beta] = 1.6 and the NA is close to its utmost, an almost 100% uniform light shell surrounding the 3D dark spot can be achieved and the dark spot is very clean. If the NA is lowered but [beta] is increased to 1.95, we can also achieve an almost 100% uniform light shell and light efficiency can reach 90%, but the disadvantage is that the center of the dark spot is not too clean. A not-too-clean 3D dark spot, if the light shell surrounding it is very uniform, is acceptable for many applications. Therefore, 3D dark spots surrounded by a high uniform light shell, generated by simply adjusting the truncation parameter of the R-[LG.sub.11] beam and the NA of the system, are useful for superresolution fluorescence microscopy, dark spot microscopy, and the dark spot trap. OCIS codes: 050.1970, 260.5430, 180.6900.

The diffraction properties of thick vector holograms were analyzed with the use of a simple coupled-wave theory. Two eigenpolarizations in the holograms were determined based on the dielectric perturbation, and diffraction efficiencies for the polarizations were calculated by applying the Kogelnik method. The results were compared with those simulated by the finite-difference time-domain method. As a result, it was demonstrated that the diffraction efficiencies calculated by the two methods are in good agreement for any incident polarization when the modulation depth of the anisotropic phase retardation is substantially smaller than the mean retardation. In addition, we confirmed that coupled-wave analysis provides reasonable accuracy for relatively large modulation in the case of Bragg incidence with eigenpolarization. OCIS codes: 050.7330, 090.1970.

We analyze the behavior of a quantum system described by a one-dimensional asymmetric potential consisting of a step plus a harmonic barrier. We solve the eigenvalue equation by the integral representation method, which allows us to classify the independent solutions as equivalence classes of homotopic paths in the complex plane. We then consider the propagation of a wave packet reflected by the harmonic barrier and obtain an expression for the interaction time as a function of the peak energy. For high energies we recover the classical half-period limit. Association of Physics Teachers. [DOI: 10.1119/1.3379290]

The problem of a charged Dirac particle crossing a gravitational electromagnetic wave of finite duration in general relativity is considered in this paper. The set of equations representing the Dirac equation in the Newman-Penrose formalism is solved exactly. It is shown that the Dirac particle crossing such a wave emerges with amplified energy. PACS Nos: 04.20, 04.30 Nous etudions ici le probleme d'une particule chargee de Dirac qui croise un champ electromagnetique gravitationnel de duree finie en Relativite Geenerale. Nous solutionnons exactement l'ensemble des equations representant l'equation de Dirac dans le formalisme de Newman-Penrose. Nous montrons que la particule de Dirac croisant une telle onde emerge avec un gain d'eenergie. [Traduit par la Redaction], 1. Introduction The focusing property of plane waves was first shown in the general case by Penrose [1]. He considered the structure of the future light cone in front of [...]

We present what is, to the best of our knowledge, the first diode-pumped Nd:LuVQ laser emitting at 1089 nm, based on the [sup.4][F.sub.3/2]-[sup.4][I.sub.11/2] transition, generally used for a 1066 nm emission. A power of 8.7 W at 1089 nm has been achieved in continuous-wave (cw) operation with a fiber-coupled laser diode emitting 18.7 W at 809 nm. Intracavity second-harmonic generation in cw mode has also been demonstrated with a power of 3.6 W at 544.5 nm by using a Li[B.sub.3][O.sub.5] nonlinear crystal. OCIS codes: 140.3530, 140.3480, 140.3515.

An alternative calculation of the path integral for the harmonic oscillator is carried out as recommended in the textbook of Feynman and Hibbs. A surprising generalization of the angle-doubling formulas for the trigonometric functions appears. Some algebraic and numerical properties of the recursion relations are analyzed and interpreted as an example of a renormalization group transformation albeit in time rather than in space. [c] 2010 American Association of Physics Teachers. [DOI: 10.1119/1.3280231]

We have generated continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling a high-power Ti:sapphire laser in an external enhancement cavity. An LBO crystal that is Brewster-cut and antireflection coated on both ends is used for a long-term stable frequency doubling. By optimizing the input coupler's reflectivity, we could generate 1.5 W 378 nm radiation from a 5 W 756 nm Ti:sapphire laser. According to our knowledge, this is the highest CW frequency-doubled power of a Ti:sapphire laser. [c] 2010 Optical Society of America OCIS codes: 190.2620, 140.3515, 140.3590.

Diffraction gratings that can be used to convert the Hermite--Laguerre--Gaussian (HLG) mode into the Gaussian mode were obtained; these modes are space modes of light beams. The HLG mode is intermediate between the Hermite--Gaussian and the Laguerre--Gaussian modes. Generally, gratings produced from interfering two beams as holograms contain information of not only the phase modulation factor but also the amplitude modulation factor. Thus, they cannot be expected to provide high conversion efficiency. To produce high-efficiency gratings, the interference equation is divided into two factors. The gratings produced by considering only the phase factors act as phase converters. [c] 2010 Optical Society of America OCIS codes: 050.1950, 050.4865, 120.5060, 140.3300.

We present a simplified spherical harmonics approximation for the time-domain radiative transfer equation including the source-divergence effect. This leads to a set of coupled partial differential equations (PDEs) of the parabolic type that model diffuse light propagation in biological-tissue-like media. We introduce a finite element approach for solving these PDEs, thereby obtaining the time-dependent spatial profile of the fluence. We compare the results with the diffusion equation and Monte Carlo simulations. The fluence obtained via our model is shown to reproduce well the Monte Carlo results in all cases and improves on the solution of the diffusion equation in homogeneous diffusive-defying media. Our solution also shows more sensitivity than the diffusion equation to changes in the absorption coefficient of small inclusions. OCIS codes: 170.3660, 170.6920.

A theory of two-stream electromagnetic wave-wiggler free-electron lasers (TSEMWFEL) with an ion-channel guiding is proposed and investigated. An analysis of the two-stream steady-state electrons trajectories is obtained by solving the equation of motion in the electromagnetic wave wiggler and ion-channel guiding. The electron trajectories and the small signal gain are derived. Numerical calculations show that there are seven group trajectories rather than the two groups reported for conventional free-electron lasers. The characteristics of the linear-gain and the normalized maximum gain are studied numerically. It was also shown that the normalized gain of groups I and II is decreased and for groups (IV-VII) are increasing by growing [[??].sub.i]. Furthermore, it was found that the two-stream with ion-channel field enhances the maximum gain in comparison with that for single beam. PACS No: 41.60.Cr Nous proposons et analysons une theorie pour un laser a electron libre avec un onduleur a deux faisceaux d'ondes electromagnetiques et canal en fer pour guider les ions (TSEMWFEL). Nous etudions les trajectoires des deux faisceaux stationnaires d'electrons en solutionnant l'equation de mouvement dans l'onduleur d'onde electromagnetique et le canal en fer pour guider les ions. Nous obtenons les trajectoires electroniques et le faible gain de signal. Les calculs numeriques montrent qu'il y sept groupes de trajectoires au lieu des deux groupes rapportes en FEL conventionnel. Nous etudions numeriquement les caracteristiques du gain lineaire et du gain maximum normalise. Nous trouvons qu'en augmentant [[??].sub.i], le gain normalise decroit pour les groupes I et II, alors qu'il croit pour les groupes IV-VII. De plus, nous observons que le champ a deux faisceau et canal de fer presente un plus grand gain maximum, lorsque compare; a celui a faisceau simple. [Traduit par la Redaction], 1. Introduction A free-electron laser (FEL) is a high-power, continuously tunable source of coherent electromagnetic radiation that uses a beam of relativistic electron passing through a long transverse magnetic field [...]

It is shown that the momentum of an electromagnetic wave in a dielectric medium can be uniquely determined to be the Minkowski momentum by considering oblique incidence of electromagnetic wave on a flat dielectric boundary. The Minkowski momentum is consistent with the Fresnel's formulae and satifies the energy and momentum conservation laws. PACS Nos: 03.50.De, 42.50.Wk Nous montrons que la quantite de mouvement de l'onde electromagnetique est sans equivoque la quantite de mouvement de Minkowski, en etudiant l'incidence oblique de l'onde electromagnetique sur la surface plane d'un dielectrique. La quantite de mouvement de Minkowski est coherente avec les formules de Fresnel et satisfait les lois de conservation de l'energie et de la quantite de mouvement. [Traduit par la Redaction], In classical electrodynamics, the momentum of an electromagnetic wave in a dielectric medium continues to be as unsettled a problem ever since the proposals of the two well known, but [...]

A thermal oxidation fabrication technique is employed to form low-loss high-index-contrast silicon shallow-ridge waveguides in silicon-on-insulator (SOI) with maximally tight vertical confinement. Drop-port responses from weakly coupled ring resonators demonstrate propagation losses below 0.36 dB/cm for TE modes. This technique is also combined with 'magic width' designs mitigating severe lateral radiation leakage for TM modes to achieve propagation loss values of 0.94 dB/cm. We discuss the fabrication process utilized to form these low-loss waveguides and implications for sensor devices in particular. OCIS codes: 130.0130, 130.3120, 130.3130, 130.2790, 130.5990.

A mechanical quartz microresonator (tuning fork) is used to detect electromagnetic radiation. The detection scheme is based on forces created due to the incident electromagnetic radiation on the piezoelectric tuning fork. A force can be created due to the transfer of the photon momentum of the incident electromagnetic radiation. If the surfaces of the tuning fork are nonuniformly heated, a second force acts on it, the so-called photophoretic force. These processes occur for all wavelengths of the incident radiation, making the detector suitable for sensing of ultraviolet, visible, and mid-infrared light, even THz-radiation. Here the detector is characterized in the visible range; noise analysis is performed for 650 nm and 5.26 [micro]m. A linear power characteristic and the dependence on pulse lengths of the incoming light ate shown. Examples for applications for the visible and mid-infrared spectral region are given by 2f and absorption spectroscopy of oxygen and nitric oxide, respectively. OCIS codes: 120.1880, 040.6808, 230.4910.

We show how to obtain the first multipole contributions to the electromagnetic radiation emitted by an arbitrary localized source directly from the Jefimenko equation for the magnetic field and the Panofsky-Phillips equation for the electric field. This procedure avoids the unnecessary calculation of the electromagnetic potentials. [DOI: 10.1119/1.2990666]

Optical properties of metal films, such as phase shift on reflection or penetration depth of electromagnetic waves into mirrors, play an important role in determining the resonance wavelength of a microcavity. We created a series of [lambda]/2 cavities with a symmetrical structure of glass/Ag/lithium fluoride/Ag by changing the thickness of the Ag film. The penetration depth at different thicknesses of Ag film was obtained from the transmittance peaks of the cavities. Phase shift on reflection at the lithium fluoride--Ag interface was calculated based on the measured optical constants. The formulation between phase shift and penetration depth was proved by experimental results, which are in good agreement with the theoretical calculations. OCIS codes: 230.4040, 310.6860.

A finite-difference time-domain method is used to study and investigate the effects of various factors, including the plasma thickness and plasma density distribution function on the attenuation of the electromagnetic wave in a thin plasma layer at high pressure. The analysis reveals that the plasmas require a certain thickness for high collision frequency to absorb microwave radiation over a wider frequency range for different plasma distributions.

We discuss a recently predicted mechanism whereby energy is produced by the background space non-holonomic field (the global space rotation) in Thomson dispersion of light in free electrons. We compare [...]

The totality of new and previous optical observations of a class of high-albedo solar system objects at small phase angles reveals a unique combination of extremely narrow brightness and polarization features centered at exactly the opposition. The specific morphological parameters of these features provide an almost unequivocal evidence that they are caused by the renowned effect of coherent backscattering. OCIS codes: 030.1670, 030.5620, 290.1350, 290.4210, 290.5850.

The transmission of an electromagnetic wave through a thick conducting grating, where the conductors are separated by a small fraction of a wavelength, is examined. The conditions for which almost all of the incident radiation can pass through are found. This theoretical result is confirmed by a microwave experiment at 35 GHz.

A hybrid simulation technique that integrates transmission line matrix method with electromagnetic topology solutions has been employed to link a field scattering problem at an aperture in order to analyze the frequency and temporal characteristics of electromagnetic pulses. The analysis shows that the aperture size affects the field propagation and penetration, influencing both the field characteristics and frequency spectral parts of the incident pulse.

The concept of light (electromagnetic radiation) outside of the visible spectrum is an abstract concept for students in an introductory science class. When students are presented with demonstrations or experiments meant to explore this portion of the spectrum, the equipment involved often hides the phenomena. A simple modification to a standard, inexpensive web camera (webcam) can take advantage of the sensitivity of the charged-coupled-device (CCD) to the infrared (IR) portion of the spectrum, allowing students to visualize many IR phenomena. This note reports how such a modified webcam can be used in lecture demonstrations and laboratory activities to study infrared phenomena including an IR light emitting diode (LED), the IR component of different light sources, IR spectroscopy, and blackbody radiation. As a final example, the modified camera can be employed to view the charcoal under-drawing of a 'painting' created for this paper and used in our classroom demonstrations. [DOI: 10.1119/1.1900105]

The advances made in the development of media with radically new optical properties and the new possibilities for nuclear optics and quantum information science is reviewed. Coherent preparation techniques that are at the heart of Electromagnetically induced transparency (EIT) can be easily implemented in optically dense atomic samples in the gas phase.

A study considers several steps of the propagation of waves in a metamaterial consisting of split ring resonators (SRRs) and metallic rods. Details of the interaction between electromagnetic and MI waves is presented in the form of a coupled dispersion equation.

A transfer matrix method is used to show that an electromagnetic wave in a cubic lattice of point dipoles propagates as if its wave speed has been reduced from c in vacuo to c/n, where n is the index of refraction, while in the interstices the wave speed is c. Because the lattice is not a continuum, there are evanescent waves between lattice planes. These waves ultimately give rise to the Lorentz-Lorenz result for n and produce rapid variations of the polarization in the first few lattice planes. These rapid variations indicate that there is an extinction length over which the external wave is converted to the internal wave propagating at the reduced speed. This length is the distance over which the local field assumes its bulk value. The possibility of an extinction length in recent work on the Ewald-Oseen theorem was missed because only continuum models were considered. [DOI: 10.1119/1.1539100]

Absorption of electromagnetic radiation by absorptive dielectric spheres such as snow grains in the near-infrared part of the solar spectrum cannot be neglected when radiative properties of snow are computed. Thus a new, to our knowledge, geometrical-optics code is developed to compute scattering and absorption cross sections of large dielectric particles of arbitrary complex refractive index. The number of internal reflections and transmissions are truncated on the basis of the ratio of the irradiance incident at the nth interface to the irradiance incident at the first interface for a specific optical ray. Thus the truncation number is a function of the angle of incidence. Phase functions for both near- and far-field absorption and scattering of electromagnetic radiation are calculated directly at any desired scattering angle by using a hybrid algorithm based on the bisection and Newton-Raphson methods. With these methods a large sphere's absorption and scattering properties of light can be calculated for any wavelength from the ultraviolet to the microwave regions. Assuming that large snow meltclusters (1-cm order), observed ubiquitously in the snow cover during summer, can be characterized as spheres, one may compute absorption and scattering efficiencies and the scattering phase function on the basis of this geometrical-optics method. A geometrical-optics method for sphere (GOMsphere) code is developed and tested against Wiscombe's Mie scattering code (MIE0) and a Monte Carlo code for a range of size parameters. GOMsphere can be combined with MIE0 to calculate the single-scattering properties of dielectric spheres of any size. OCIS codes: 080.2720, 290.5850, 120.0280, 010.2940, 160.4760.

Single-gap pseudosparks are examined in detail through experimental investigation. The breakdown characteristics for voltage sparks are assessed.

Statistical equilibrium equations are used to calculate ratios for line intensities, for plasmas which have been developed through the usage of laser ablation.

The impact of adding Ar to a plasma formed of O2 is examined in detail in the context of a large area plasma source which is wave dirven and inductively coupled.

Finite nonzero inertial delay has certain implications in relation to acoustic oscillations where an ion-beam plasa system is used. These implications are examined in detail.

Plasam-neutral gas structures are examined in detail. A model is developed with a number of elements and is compared with the results of an experiment.

Research describing millimeter-wave microscopy is presented. A simplified model is developed whereby a parallel plate waveguide opens into a ground plane and radiates in the proximity of a perfectly conducting strip.

The experimental and theoretical axial distributions of the electrons and 3p(sup 5)4s and 3p(sup 5)4p excited atoms in argon plasma columns sustained by moving electromagnetic waves are studied. The theoretical model includes a self-consistent solution to the electron Boltzmann equation, thus balancing a good agreement between experimental data and theoretical results.

A quantitative analysis was conducted to better understand the vertical electric dipole-induced waves that propagate through the electrically homogenous sphere. Results show that the waves propagate along a straight line inside the sphere. The waves' geometry was visualized in terms of ray optics, instead of geometrical optics which failed to produce adequate prediction of the complex amplitude of the wave behavior.

A 0.25 micrometer InP diode with an RL circuit generates microwave power with a high-frequency range between 350 gigahertz and 750 gigahertz. Inductance L of the circuit, tunes the generation frequency to this range. Frequencies of 500 gigahertz exhibit the powerful generation frequency. Monte Carlo particle simulation technique for various bias values helps determine noise spectral power densities.

A Brillouin-like dispersion diagram aids in determining the dispersion association of the six waves formed in the instantaneously produced two-resonance lossy Lorentz medium consisting two distinct types of molecules or atoms. A maximum of 4% of the pump wave power changes into the reflected modes. Two new waves, whose power transmission, amplitude and reflection coefficients are determined, are excited.

Second-harmonic generation brought about by electric fields in organic nonlinear optical materials was investigated using a technique which limited interference between two second-harmonic waves from a solution and a cell-window glass. The method proved to be more suitable for measuring second-order and third-order hyperpolarizabilities in materials with low solubility.

A theoretical formulation of electron pulse propagation in quantum wire structures with mesoscopic scale cross sections was presented. The formulation assumed the quantum ballistic transport of electron wave packets over the phase coherence length. The walk-off, the dispersion and the pulse coherence lengths were defined as representative characteristic lengths for the estimation of temporal features and variations of the pulse during propagation.