arXiv subjects
Publications and source records attributed to Igor I. Smolyaninov.
We have observed enhanced transmission of light through a gold film due to excitation of standing surface plasmon Bloch waves in a surface Fabry-Perot resonator. Our experimental results strongly contradict the recently suggested model of light transmission via excitation of a composite diffractive evanescent wave.
Temporal fluctuations of the speckle pattern formed upon backscattering of a laser beam from an interface between gold and nonlinear polymer film have been observed as a function of optical power. The instability can be explained by coupling of laser light to surface plasmons and other guided modes, which experience multiple scattering while propagating in the film along the interface. The speckle pattern produced in this process is extremely sensitive to fluctuations of the scattering potential near the interface.
We demonstrate that surface plasmon polaritons can be guided by nanometer scale dielectric waveguides. In a test experiment plasmons were coupled to a curved 3 micrometer radius dielectric stripe, which was 200 nm wide and 138 nm thick using a parabolic surface coupler. This experiment demonstrates that using surface plasmon polaritons the scale of optoelectronic devices based on dielectric waveguides can be shrunk by at least an order of magnitude.
Optical entropy bounds for metal nanoparticles immersed in nonlinear optical media and for nonlinear dielectric microdroplets on metal surfaces are calculated near the frequency of the surface plasmon resonance. Similar to the Bekenstein-Hawking result for the black hole entropy, the entropy bounds in nonlinear quantum nanooptics may be expressed as the ratios of the droplet perimeter (nanoparticle area) to the effective Planck length (effective Planck length squared).
Theoretical model of the enhanced optical resolution of the surface plasmon immersion microscope is developed, which is based on the optics of surface plasmon Bloch waves in the tightly bound approximation. It is shown that a similar resolution enhancement may occur in a more general case of an immersion microscope based on photonic crystal materials with either positive or negative effective refractive index. Both signs of the effective refractive index have been observed in our experiments with surface plasmon immersion microscope, which is also shown to be capable of individual virus imaging.
Plasmon-polariton behavior on the surfaces of constant negative curvature is considered. Analytical solutions for the eigenfrequencies and eigenfunctions are found, which describe resonant behavior of metal nanotips and nanoholes. These resonances may be used to improve performance of metal tips and nanoapertures in various scanning probe microscopy and surface-enhanced spectroscopy techniques.
Optically active localized plasmon modes may be very abundant on a rough surface of a metal wire. Zero-point fluctuations of these modes are shown to produce local DC magnetization. Thus, the effect of these modes on the electron dephasing time is similar to the effect of magnetic impurities.
A new far-field optical microscopy technique capable of reaching nanometer-scale resolution has been developed recently using the in-plane image magnification by surface plasmon polaritons. This microscopy is based on the optical properties of a metal-dielectric interface that may, in principle, provide extremely large values of the effective refractive index n up to 100-1000 as seen by the surface plasmons. Thus, the theoretical diffraction limit on resolution becomes lambda/2n, and falls into the nanometer-scale range. The experimental realization of the microscope has demonstrated the optical resolution better than 50 nm for 502 nm illumination wavelength. However, the theory of such surface plasmon-based far-field microscope presented so far gives an oversimplified picture of its operation. For example, the imaginary part of the metal dielectric constant severely limits the surface-plasmon propagation and the shortest attainable wavelength in most cases, which in turn limits the microscope magnification. Here I describe how this limitation has been overcome in the experiment, and analyze the practical limits on the surface plasmon microscope resolution. In addition, I present more experimental results, which strongly support the conclusion of extremely high spatial resolution of the surface plasmon microscope.
Zero-point fluctuations of surface plasmon modes near the interface between metal and nonlinear dielectric are shown to produce a thin layer of altered dielectric constant near the interface. This effect may be sufficiently large to produce multiple metastable states of the surface plasmon vacuum.
The resolution of far-field optical microscopes, which rely on propagating optical modes, is widely believed to be limited because of diffraction to a value on the order of a half-wavelength $λ/2$ of the light used. Although immersion microscopes have slightly improved resolution on the order of $λ/2n$, the increased resolution is limited by the small range of refractive indices n of available transparent materials. Here we demonstrate a new far-field optical microscope design, which is capable of reaching nanometer-scale resolution. This microscope uses the fact that the effective refractive index $n_{eff}$ of a planar dielectric lens or mirror placed on a metal surface may reach extremely large values, up to $10^3$, as seen by propagating surface optical modes (plasmons). In our design a magnified planar image produced originally by surface plasmons in the metal plane is viewed by a regular microscope. Thus, the theoretical diffraction limit on resolution is pushed down to nanometer-scale $λ/2n_{eff}$ values. Used in reverse, such a microscope may become an optical lithography tool with nanometer-scale spatial resolution.
Recently introduced toy surface plasmon "black holes" and "wormholes" (New Journal of Physics 5, 147.1-147.8 (2003), and gr-qc/0306089) can be used to create a toy "time machine" according to a number of published designs (see for example I.D. Novikov, Sov.Phys.JETP 68, 439 (1989)). Assuming that such a toy "time machine" does not work, a general prediction can be made of strong electromagnetic field enhancement inside an arbitrarily-shaped nanohole near an arising effective event horizon, which is supposed to prevent the toy "time machine" from being operational. This general result is useful in description of the nonlinear optical behavior of random nanoholes in metal films.
Spectral dependencies of polarized optical transmission of a metal film with a periodic array of elliptical nanoholes have been studied. Such nanostructured metal films exhibit the enhanced broadband optical transmission which can be controlled by selecting polarization of incident and/or transmitted light.
Nonlinear optical behavior of recently introduced surface plasmon toy black hole models has been considered. Physical realization of these models involves droplets of liquid on a metal surface, which supports propagation of surface plasmons. Such droplets are shown to exhibit strongly enhanced nonlinear optical behavior in the frequency range near the surface plasmon resonance of a metal-liquid interface. This enhancement may be responsible for the missing orders of magnitude of field enhancement in the surface enhanced Raman scattering effect. In addition, experimental observation of the recently predicted optical second harmonic generation near the toy event horizon is reported. Finally, the possibility of toy Hawking radiation observation is discussed, and the expression for the effective Hawking temperature of a toy surface plasmon black hole is derived. The effective Hawking temperature appears to be in the range of a few hundreds Kelvin for the realistic droplet shapes, which may lead to a surprising conclusion that the shapes of the liquid droplets on metal substrates are to some degree determined by the Hawking radiation.
Recently introduced surface plasmon toy black hole model has been extended in order to emulate a rotating black hole (Kerr metric). Physical realization of this model involves a droplet of an optically active liquid on the metal surface which supports propagation of surface plasmons. Such droplets are shown to exhibit giant optical activity in the frequency range near the surface plasmon resonance of a metal-liquid interface.
Nonlinear mode coupling in a coaxial waveguide filled with Faraday material has been considered. The picture of mode interaction is shown to resemble Coulomb interaction of charges: higher modes with nonzero angular momentum interact like effective charges via exchange of zero angular momentum quanta of the fundamental mode. Thus, at large distances this interaction becomes the dominant mechanism of mode coupling. The developed model may be used in designing coaxial photonic crystal fibers with strong tailored mode interaction.
Surface plasmons at metal interfaces are collective excitations of the conduction electrons and the electromagnetic field. They exist in "curved three-dimensional space-times" defined by the shape of the metal surface and the spatial distribution of the dielectric constant near the surface. Here we show that surface plasmon toy models of many non-trivial space-time metrics, such as wormholes and black holes, can be easily built and studied in experiments. For example, a droplet of dielectric on the metal surface behaves as a black hole for surface plasmons within a substantial frequency range. On the other hand, a nanohole in a thin metal membrane may be treated as a wormhole connecting two "flat" surface plasmon worlds located on the opposite interfaces of the membrane.
In this paper we report on the observation of novel and highly unusual magnetic state of light. It appears that in small holes light quanta behave as small magnets so that light propagation through such holes may be affected by magnetic field. When arrays of such holes are made, magnetic light of the individual holes forms novel and highly unusual two-dimensional magnetic light material. Magnetic light may soon become a great new tool for quantum communication and computing.
Similarities between nonlinear electron-plasmon interactions in a cylindrical mesoscopic system and Kaluza-Klein theories, which stem from the analogy between the angular coordinate of a nanocylinder with the compactified coordinates of the Kaluza-Klein theories, have been considered. These similarities indicate that electron and plasmon states with non-zero angular momenta exhibit strong long-range interaction with each other via exchange of plasmons with zero angular momentum. This insight has been confirmed by finding correspondent solutions of the nonlinear Maxwell equations for interacting plasmons. Such solutions have important consequences for description of electromagnetic and transport properties of mesoscopic metallic wires, holes and rings, such as recent observation of density-dependent spin polarization in quantum wires. Numerical estimates indicate that the latter effect can be explained by the electron energy level splitting in the gyration field induced due to the magneto-optical effect by the current flowing through the quantum wire.