A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Recent years have seen a rapid expansion of research into nanophotonics based on surface plasmon–polaritons. These electromagnetic waves propagate along metal–dielectric interfaces and can be guided by metallic nanostructures beyond the diffraction limit. This remarkable capability has unique prospects for the design of highly integrated photonic signal-processing systems, nanoresolution optical imaging techniques and sensors. This Review summarizes the basic principles and major achievements of plasmon guiding, and details the current state-of-the-art in subwavelength plasmonic waveguides, passive and active nanoplasmonic components for the generation, manipulation and detection of radiation, and configurations for the nanofocusing of light. Potential future developments and applications of nanophotonic devices and circuits are also discussed, such as in optical signals processing, nanoscale optical devices and near-field microscopy with nanoscale resolution.

Plasmonics beyond the diffraction limit

The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Plasmons in strongly coupled metallic nanostructures.

Quantum plasmonics is a rapidly growing field of research that involves the study of the quantum properties of light and its interaction with matter at the nanoscale Here, surface plasmons - electromagnetic excitations coupled to electron charge density waves on metal-dielectric interfaces or localized on metallic nanostructures - enable the confinement of light to scales far below that of conventional optics In this article we review recent progress in the experimental and theoretical investigation of the quantum properties of surface plasmons, their role in controlling light-matter interactions at the quantum level and potential applications Quantum plasmonics opens up a new frontier in the study of the fundamental physics of surface plasmons and the realization of quantum-controlled devices, including single-photon sources, transistors and ultra-compact circuitry at the nanoscale

Quantum Plasmonics

Active switching of plasmons by an external magnetic field is demonstrated in a metal–ferromagnet–metal structure. The strong modulation, combined with possible all-optical magnetization reversal induced by femtosecond light pulses, opens the door to ultrafast magneto-plasmonic switching.

/pdf/active-magneto-plasmonics-in-hybrid-metal-ferromagnet-1sj7edpazf.pdf

Active magneto-plasmonics in hybrid metal–ferromagnet structures

A silver-nanowire cavity is functionalized with CdSe nanocrystals and optimized towards cavity quantum electrodynamics by varying the nanocrystal-nanowire distance d and cavity length L. From the modulation of the nanocrystal emission by the cavity modes a plasmon group velocity of v (gr) approximately 0.5c is derived. Efficient exciton-plasmon-photon conversion and guiding is demonstrated along with a modification in the spontaneous emission rate of the coupled exciton-plasmon system.

Exciton-plasmon-photon conversion in plasmonic nanostructures.

Surface plasmon–polaritons are electromagnetic waves that propagate along metal–dielectric interfaces and exist over a wide range of frequencies. They have become popular research tools owing to their subwavelength confinement and potential ability to perform ultrasensitive optical measurements. Driven by tremendous progress in nanofabrication techniques and ultrafast laser technologies, the applications of surface plasmon–polariton nano-optics extend beyond nanoplasmonics. In this Review, we discuss how the use of hybrid multilayer structures combining different functionalities allows the development of active plasmonic devices and new metrologies. Magneto-plasmonics, acousto-plasmonics and the generation of high-energy photoelectrons using ultrashort surface plasmon–polariton pulses are all examples of how the combination of ideas developed in these individual fields can be used to generate new knowledge, leading to a range of exciting applications in nanophotonics. Surface plasmon polaritons have become popular because of their sub-wavelength confinement and the possibility to perform ultrasensitive optical measurements. This article reviews the development of active plasmonic devices and new metrologies using hybrid multilayer structures combining with the magnetic, acoustic and ultrafast effects.

Ultrafast acousto-magneto-plasmonics

Ionization mechanisms in bulk dielectrics irradiated by single intense 50-fs-laser pulses are investigated by ultrafast time-resolved imaging interferometry. Polarization-sensitive 6-photon ionization is shown to be the dominant ionization mechanism in fused silica and sapphire at intensities around $10\text{ }\text{ }\mathrm{TW}/{\mathrm{cm}}^{2}$. For both materials the cross sections of 6-photon ionization are found to be significantly higher for linear polarization than for circular. Our experimental results corroborate an earlier theoretical prediction on the dominance of linear polarization in high-order multiphoton ionization.

http://www.ilp.physik.uni-essen.de/vonderLinde/Publikationen/Temnov06PRL97_237403.pdf

Multiphoton ionization in dielectrics: comparison of circular and linear polarization.

The collective spontaneous emission of a fully inverted inhomogeneously broadened ensemble of $N$ two-level systems coupled to a single-mode low-$Q$ cavity is investigated numerically using Monte Carlo wave function technique. An intrinsically bi-exponential emission dynamics is found when the time scales of superradiance ${\ensuremath{\tau}}_{\mathrm{sr}}$ and inhomogeneous dephasing ${T}_{2}^{*}\ensuremath{\sim}1/\ensuremath{\Delta}{\ensuremath{\omega}}_{\mathrm{inh}}$ become comparable: a fast superradiant is followed by a slow subradiant decay. Experimental configurations using ensembles of quantum dots coupled to optical microcavities are proposed as possible candidates to observe the combined superradiant and subradiant energy relaxation.

Vasily V. Temnov

Papers

Active magneto-plasmonics in hybrid metal–ferromagnet structures

Exciton-plasmon-photon conversion in plasmonic nanostructures.

Ultrafast acousto-magneto-plasmonics

Multiphoton ionization in dielectrics: comparison of circular and linear polarization.

Superradiance and subradiance in an inhomogeneously broadened ensemble of two-level systems coupled to a low-Q cavity.