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Summary form only given. We present data that moves beyond this paradigm by exploring both spectral/spatial correlations between eigenstates of a disordered quantum well and examining spatial properties of the eigenstate itself. Unlike earlier work which relied on spectral and spatial diffusion for signal, degenerate cw nonlinear spectroscopy is utilized as an 'absorption-like' probe capable of mapping...
Summary form only given. We consider two resonant molecules (or nano-particles) located near the tip of an apertureless near-field scanning optical microscope (NSOM). The tip serves as a probe that allows us to observe the molecules and control the coupling between them. Various models are considered for the nanosized probe tip: a point-like dipole, a small dielectric sphere, and an elongated spheroidal...
Summary form only given. With the advent of scanning near-field optical microscopy (SNOM) ultrahigh-resolution optical microscopy has attracted renewed interest. Although after more than a decade the conventional mode of SNOM that uses a subwavelength aperture has bottomed out at a resolution of roughly 50 nm, an unlimited resolution could be expected in optical near-field microscopy. One of the conceptually...
Summary form only given. A single fluorescent molecule in an isotropic medium acts as a dipole radiator. In a locally heterogeneous environment the angular emission pattern is modified. Recently Novotny (1996) calculated strongly peaked angular emission when the emitter is brought in close proximity to a strong dielectric-metal gradient. We believe we present the first direct observation of this prediction;...
Summary form only given. Recently, atom manipulation by using optical near fields has been attracting a lot of interests. Optical near field can be localized in a nanometric region, being free from the diffraction limit in contrast to propagation light. The intensity distribution of optical near field decays rapidly as an exponential-like function. Because such a spatially inhomogeneous light field...
Summary form only given. There is intense current interest in the dynamical properties of self-organized InAs quantum dots from fundamental and applied viewpoints. We report here measurement and analysis of the depopulation dynamics of the lowest electronic states following resonant excitation by a femtosecond pulse. Our results, obtained by using a high-sensitivity differential transmission technique...
Summary form only given. Recent experimental studies have revealed distinct characteristics of optical near fields. Highly localized optical near fields could be applied to not only a high-resolution microscope beyond the diffraction limit of light but also fabrication of nanometric devices. From this point of view, a theory, which quantitatively deals with interactions between a nanometric probe...
Summary form only given. It is well-known that nonlinear interference effects in the resonant atom-light interaction can lead to interesting and important phenomena, such as electromagnetically induced transparency (EIT) of atomic medium, coherent population trapping, lasing without inversion, and others. Common to all these phenomena is the appearance of light-induced coherence between atomic levels,...
Summary form only given. Photonic crystals can be employed as the substrates of planar antenna to minimize or eliminate the radiation energy loss into the substrate. Previously, surface waves of two-dimensional (2D) photonic crystals has been studied in the case that a complete bandgap exists for only one polarization state. We study the surface waves of a 2D photonic crystal with a complete photonic...
Summary form only given. Excitons confined in nanocrystals or quantum dots attract much attention because they have a very long phase relaxation time that opens the way to the artificial coherent control of the excitons. CuCl quantum dot is a typical material in which the translational motion of the exciton is confined. In this paper, we report on the high resolution measurement of the resonant luminescence...
Summary form only given. Because of their small nanometer size and strong electronic confinement, quantum dots exhibit zero-dimensional electronic and optical effects which continue to be interesting for physics and promising for applications. To study single and clusters of self-organized semiconductor quantum dots, near-field optical nanoprobing is a powerful tool. Its spatial resolution surpasses...
Summary form only given. In a coherent control four-wave mixing (FWM) experiment, a first pulse, 1, can excite a certain electron-hole pair density n/sub eh/ in a semiconductor. Because this density is connected with interband coherence, a second phase locked and time-delayed pulse, 1', adjusted for destructive interference, can lead to a coherent reemission of photons. As a result, a first light...
Summary form only given. A system of indirect (interwell) excitons in coupled quantum wells (CQWs) provides a unique opportunity for experimental study of two-dimensional light composite bosons thermalized down to ultralow temperatures. The long recombination lifetime of indirect excitons promotes the exciton accumulation in the low energy exciton states and allows the system to cool down to temperatures...
Summary form only given. We present some results of rigorous calculations for a photonic crystal film positioned between two semi-infinite regions of uniform refractive index, where the photonic crystal film itself is a triangular lattice of cylindrical holes etched into a medium having a higher refractive index than the semi-infinite regions. We start by considering a photonic crystal film of infinite...
Summary form only given. To understand the fundamental properties of an atom, precise measurement of the atomic resonance frequency is important. The main factor that restricts the precision is the spectral broadening. Spectral narrowing by recurrent use of free decay signal in magnetic resonance was proposed and demonstrated in the ground state of Rb atoms. In the present report we apply this technique...
Summary form only given. Single crystals of the polydiacetylene, poly[2,4-hexadiyne-1,6-diol-bis(p-toluenesulfonate)] (pTS) have been studied in the near resonant regime by transient absorption spectroscopy. We show the changes observed in the absorption spectra at short times surrounding the arrival of the 726-nm laser pulse. The experiment is performed by monitoring the transmission of a continuum...
Summary form only given. Isochronous electric field gradients have been used to deflect beams of molecules and neutral atoms. However, time-varying electric field gradients can be used to accelerate, slow, cool, or bunch these same beams. The method works best for polar molecules with large dipole moments and atoms with large polarizabilities.
Summary form only given. Atomic lifetime measurements are important probes of atomic structure because they depend on the initial and final state wave functions and the interaction that connects them. The study of francium, the heaviest alkali, has two advantages over other heavy elements. It has a simple atomic structure to calculate accurately, and it is possible to trap it with the well developed...
Summary form only given. The essence of the "strong correlation" problem is that interactions reduce the ability of electrons to move in a solid. Optical conductivity probes, over a wide range of time scales, the ability of electrons to move, and is therefore a key probe of correlated electron physics. One simple and robust feature of the conductivity is the "spectral weight,"...
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