Specifics of electromagnetic TE waves splitting and combining under the conditions of frustrated total internal reflection in a thin dielectric layer

The possibility of designing optical beam splitters based on frustrated total internal reflection (FTIR) is considered. A theory describing splitting of a single light wave into two waves and interference of two light waves in a thin dielectric gap under the FTIR conditions is presented. The resulting expressions are analyzed, and the curves describing the behavior of light beams in the process of their splitting and combining in a thin dielectric layer under the FTIR conditions are plotted.     

受抑全反射的微波实验研究

首先回顾了受抑全反射的历史背景和广泛的应用价值,然后分析了受抑全反射的理论机制,得到相应的倏逝波透射率公式;并且建立了一套简单的实验装置系统,研究了受抑全内反射(FTIR)的透射率和空气薄膜厚度、偏振方向之间的关系.所得结果和理论分析符合的很好.     

Nonlinear total internal reflection of electromagnetic waves

We study the stationary solution of an unstable system of interacting inhomogeneous electromagnetic waves and an acoustic wave. It is shown that the instability of this system is of hard type and the threshold of its vanishing is smaller than the excitation threshold. When the amplitude of the incident wave exceeds the threshold value there occurs interaction with partial nonlinear layer transmission, which is changed by large reflection for a large wave amplitude. In this case, the total reflection in the direction opposite to the incident wave and in the specular direction can be greater than in the absence of interaction. A parameter region in which the backward reflection dominates the specular reflection is shown. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 9, pp. 1132–1143, September, 1997.     

Theory of frustrated total internal reflection: Superluminal singularities of optical waveguides

Classical approach to frustrated total internal reflection (FTIR) does not describe its temporal properties, that are additionally considered and their superluminal singularity is shown. The transition to quantum electrodynamics shows that momenta of photons are reduced at FTIR relative to energy, i.e. it is the tunnel process, the nonlocal manifestation of near field. The tunneling consists in the instantaneous jump of excitations (virtual photons) onto definite distance, and can be described by equation having certain instanton features. Thus, the possibility of signal transfer with superluminal group velocity via optical fibers is substantiated that conforms to certain supervisions. Such properties of FTIR near field may explain, in principle, some other observed phenomena.     

Excitation of surface electromagnetic waves at an anisotropically conducting vacuum-metamaterial interface by the attenuated total internal reflection method

The excitation of well-localized oblique surface waves above the surface of a dielectric with a one-dimensional array of perfectly conducting wires is studied theoretically using the attenuated total internal reflection method. It is assumed that the distance between the wires and their diameter are much smaller than the surface wavelength. The frequencies of excited surface waves are much lower than the plasma frequency of the metal, and their electric field is orthogonal to the wires. It is shown that such surface waves can be excited with the help of a homogeneous TM wave as well as with the help of a homogeneous wave with an electric field polarized perpendicularly to the wires. It is found that in the course of excitation of oblique waves, the incident TM wave is partly polarized into a wave of the TE type.     

Confronting the Hartman effect with data from frustrated total internal reflection (FTIR)

Over 40 years ago, Hartman noted that the tunneling time τ of a particle through a barrier becomes independent of width for thick barriers. Lately, the Hartman effect has been seen as a support for superluminal tunneling time. By interpreting the reflection and transmission amplitudes in terms of multiple reflection series, we show that τ is linear in barrier width for thin barriers and may be associated with actual traversal time; for thick barriers, τ saturates to the Hartman value because of the suppression of all but the first term of the series due to the smallness of the tunneling factor. For large widths, τ cannot be identified with the propagation time but may be associated with a time to penetrate to a characteristic depth into the barrier, which is independent of width. We discuss data from frustrated internal reflection experiments, which support this view.     

Inelastic processes in the interaction of an atom with an ultrashort electromagnetic pulse

Electron transitions occurring during the interaction of a heavy relativistic atom with a spatially inhomogeneous ultrashort electromagnetic pulse are considered by solving the Dirac equation. The corresponding transition probabilities are expressed in terms of known inelastic atomic form factors, which are widely used in the theory of relativistic collisions between charged particles and atoms. By way of example, the inelastic processes accompanying the interaction of ultrashort pulses with hydrogen-like atoms are considered. The probabilities of ionization and production of a bound-free electron-positron pair on a bare nucleus, which are accompanied by the formation of a hydrogen-like atom in the final state and a positron in the continuum, are calculated. The developed technique makes it possible to take into account exactly not only the spatial inhomogeneity of an ultrashort electromagnetic pulse, but also the magnetic interaction.     

Tunneling of X-ray photons through a thin film under total internal reflection conditions

Tunneling of 0.154-and 0.139-nm x-ray photons through a thin film under total internal reflection conditions has been experimentally demonstrated. The NiSi₂ film 13 nm thick is deposited by magnetron sputtering on a polished Si substrate. A beam with an angular spread of 20″ is directed to the Si/NiSi₂ interface from the inside through the lateral surface of a sample. A peak associated with tunneling of photons from Si to air through the NiSi₂ film is observed at grazing angles of θ₁ > 0.4θ_c, where θ_c is the critical angle of total internal reflection at the Si/NiSi₂ interface. The integral intensity of tunneling peaks that is measured for various θ₁ angles agrees with the calculations.     

Measurement of the thickness of thin polymer layers by infrared frustrated total internal reflection spectroscopy

A method is proposed for determining the thickness of thin (0.1–5.0 μm) polymer layers and coatings by means of infrared frustrated total internal reflection (FTIR) spectroscopy. This method is based on an analytic expression derived for the dependence of the intensities of absorption bands in IR FTIR spectra on the thickness of a polymer layer. The method is tested on model samples consisting of a thick film of polyethylene terephthalate with a layer of different thicknesses of polystyrene deposited on it. The advantage of this method is the ability to determine the thickness of thin polymer layers deposited on bulk or opaque polymer substrates. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 6, pp. 881–885, November–December, 2008.     

Circular polarization beam splitter that uses frustrated total internal reflection by an embedded symmetric achiral multilayer coating

A symmetric achiral trilayer structure, which consists of a high-index center layer sandwiched between two identical low-index films and embedded in a high-index prism, is designed to produce equal and opposite quarter-wave retardation in reflection and transmission and equal throughput for the p and s polarization at oblique incidence. Such a device splits a beam of incident linearly polarized light into two orthogonally circularly polarized components of equal power that travel in different directions. A visible (633-nm) design that operates at a 60 degree angle of incidence and an infrared (10.6-microm) 45 degree cube design are presented. The spectral and angular sensitivities of the device are also considered.     

On nonspecular “total internal reflection” of powerful electromagnetic waves

It is shown that the nonstable character of nonlinear interaction of a system of waves similar to that resulting from double stimulated Brillouin scattering is retained upon the oblique incidence of a powerful electromagnetic wave on a layer of supercritical plasma. In this case we have nonlinear back reflection from a layer of supercritical plasma. The threshold intensity of the pump wave is greater than that in the case of subcritical plasma for TE polarization waves but can markedly decrease for waves polarized in the incidence plane. Instability is possible only for a layer of finite thickness.Radiophysical Research Institute, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, Nos. 3–4, pp. 298–303, March–April, 1995.     

Pumping of electromagnetic energy via multiple total internal reflection from active media

An experiment for strong light amplification at multiple total reflections from active gaseous media is proposed.     

Emission of an atom during its interaction with an ultrashort pulse of electromagnetic field

The electronic transitions and emission of an atom during its interaction with a spatially inhomogeneous ultrashort pulse of electromagnetic field are considered. The probabilities of excitation and ionization, as well as the spectra and cross sections of reemission of such a pulse by the atom, are obtained. As an example, the one-and two-electron inelastic processes accompanying the interaction of ultrashort pulses with hydrogen-and helium-like atoms are considered.     

Excitation of nonradiative surface plasma waves in silver by the method of frustrated total reflection

A new method of exciting nonradiative surface plasma waves (SPW) on smooth surfaces, causing also a new phenomena in total reflexion, is described. Since the phase velocity of the SPW at a metal-vacuum surface is smaller than the velocity of light in vacuum, these waves cannot be excited by light striking the surface, provided that this is perfectly smooth. However, if a prism is brought near to the metal vacuum-interface, the SPW can be excited optically by the evanescent wave present in total reflection. The excitation is seen as a strong decrease in reflection for the transverse magnetic light and for a special angle of incidence. The method allows of an accurate evaluation of the dispersion of these waves. The experimental results on a silver-vacuum surface are compared with the theory of metal optics and are found to agree within the errors of the optical constants.     

Scattering of an ultrashort electromagnetic radiation pulse by an atom in a broad spectral range

The scattering of an ultrashort electromagnetic pulse by atomic particles is described using a consistent quantum-mechanical approach taking into account excitation of a target and nondipole electromagnetic interaction, which is valid in a broad spectral range. This approach is applied to the scattering of single- and few-cycle pulses by a multielectron atom and a hydrogen atom. Scattering spectra are obtained for ultrashort pulses of different durations. The relative contribution of “elastic” scattering of a single-cycle pulse by a hydrogen atom is studied in the high-frequency limit as a function of the carrier frequency and scattering angle.     

Design of high-efficiency diffraction gratings based on total internal reflection for pulse compressor

We present designs of high-efficiency compression grating based on total internal reflection (TIR) for picosecond pulse laser at 1053 nm. The setup is devised by directly etching gratings into the bottom side of a prism so that light can successfully enter (or exit) the compression grating. Dependence of the −1 order diffraction efficiencies on the constructive parameters is analyzed for TE- and TM-polarized incident light at Littrow angle by using Fourier modal method in order to obtain optimal grating structure. The electric field enhancement within the high-efficiency TIR gratings is regarded as another criterion to optimize the structure of the TIR gratings. With the criterion of high diffraction efficiency, low electric field enhancement and sufficient manufacturing latitude, TIR compression gratings with optimized constructive parameters are obtained for TE- and TM-polarized incident light, respectively. The grating for TE-polarized light exhibits diffraction efficiencies higher than 0.95 within 23 nm bandwidth and relatively low square of electric field enhancement ratio of 5.7. Regardless of the internal electric field enhancement, the grating for TM-polarized light provides diffraction efficiencies higher than 0.95 within 42 nm bandwidth. With compact structure, such TIR compression gratings made solely of fused silica should be of great interest for application to chirped pulse amplification (CPA) systems.     

Self-referencing measurement of an ultrashort pulse by the standard shear interferometry method

A new method for the self-referencing measurement of the amplitude-phase shape of an ultrashort pulse is proposed. The method uses a two-frequency characteristic of the pulse, which is defined as S(F ₁)S(F ₂), where F is the frequency, S(F) is the complex Fourier spectrum of the pulse, and F ₁ and F ₂ are two independent variables. It is shown that this characteristic can be generated as a two-dimensional polychromatic light wave upon generation of the sum frequency of two crossed spectral decompositions of one and the same pulse, as well as upon space-time Fourier transform of radiation of the noncollinearly generated second harmonic of the pulse. In an orthogonal system of transverse coordinates F ₁ + F ₂ and F ₁ ? F ₂, at any given value of F ₁ + F ₂, the radiation frequency of this wave in the direction of the second coordinate F ₁ ? F ₂ does not change. Therefore, the phase structure of the two-frequency characteristic can be reconstructed by the standard method of lateral shear interferometry in the direction of this coordinate. In the reconstructed two-dimensional phase structure of the two-frequency characteristic, any section by the plane F ₁ = const or F ₂ = const yields the phase structure of the spectrum of the pulse under study. This makes it possible to reconstruct the amplitude-phase shape of the pulse.     

Electron transitions and the spectrum of radiation emitted by an atom interacting with an ultrashort electromagnetic pulse

Electron transitions and the spectrum of radiation emitted by an atom interacting with an ultrashort electromagnetic pulse are studied based on the sudden perturbation approximation. The excitation and ionization probabilities, the spectra of pulse reradiation by the atom, and the reradiation cross sections are calculated. It is concluded that the reradiation of ultrashort electromagnetic pulses by multielectron atoms is of a coherent nature.