The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Summary form only given. The 1980s/1990s have witnessed an intense investigation of electromagnetic wave propagation phenomena at optical frequencies in periodic structures. These structures are usually referred to as photonic band gap (PBG) crystals. Despite the fact that most applications currently available make use of the linear properties of PBGs, the study of nonlinear dynamics has also been...
Summary form only given. Nanoscale structures can be tailored to provide enhanced, nanoscale near-field optics. For example, high-quality GaAs quantum dots can be fabricated by self-formed growth near the apex of AlGaAs tetrahedral pyramids. Photoluminescence studies have shown a thousand-fold enhancement of the far-field emission of an embedded quantum dot. This large enhancement arises because the...
Summary form only given. Several experiments have been performed in optical fibers to generate photon-number squeezed pulses of light. Among these, are experiments employing a spectral filter to exploit the spectral correlations created during pulse propagation along a fiber. We recently reported the generation of photon-number squeezing in an AlGaAs waveguide as a result of multi-photon absorption...
Summary form only given. Semiconductor quantum dots (QDs) of nanometer size are of particular interest because carriers are confined there within dimensions smaller than their de-Broglie wavelength. We present the first measurements of near field time-resolved spectroscopy via single semiconductor QD, together with a theoretical model, which quantitatively describes our measurements.
Summary form only given. Complementarity is one of the most basic principles of quantum mechanics. A quantum mechanical object, be it a photon or a massive particle, shows position (particle-like) or momentum (wave-like) attributes exclusively depending on the experimental situation. Over the years, Young's two-slit experiment has been emphasized as a good example of complementarity. We report two...
Summary form only given. The optical response of self-assembled quantum dots (SAQDs) has been an area of extensive research in recent years, driven both by an interest in the basic physics of these strongly confined systems, and by the possibility of practical applications for such structures. There have been several studies of carrier relaxation in these systems, including differential transmission,...
Summary form only given. The largest blue-shift in air under a focused intense laser beam has attracted much attention. We report the supercontinuum generation in 1-atm nitrogen and oxygen respectively. The experiments were carried out with a 10-Hz Ti:sapphire chirped-pulse amplification laser system. It delivered pulses of 10 mJ maximum energy and wavelength centered at 805 nm. In the experiments,...
Summary form only given. Resonant optics at a gas-solid interface can exhibit unprecedented sensitivity to gas-surface interactions if one restricts the gas volume that determines the optical response to very small distances to the surface. In the case of evanescent wave or surface plasmon spectroscopy the excited gas volume is limited by the depth of the wave penetration into the gas. Due to this...
Summary form only given. Passive optical limiters are used to protect human eyes or sensitive optical elements from laser damage. Excited-state absorption (ESA) evoked transitions from one excited state to a higher one is a prerequisite for efficient optical limiting. Numerous parameters of the system as well as laser pulse characteristics make it difficult to determine optimum conditions for efficient...
Summary form only given. Several measurement methods of nonlinear optical Kerr coefficient n/sub 2/ in optical fibers have recently been proposed, bringing into evidence the different contributions of the electronic and electrostrictive parts, respectively n/sub 2k/ and n/sub 2e/, where electrostriction plays an important role at optical modulation frequency lower than 1.5 GHz, and is intrinsically...
Summary form only given. Recent development of micro-photoluminescence (/spl mu/-PL) spectroscopy has enabled us to observe photoluminescence from a single quantum dot, which has sharp homogeneous linewidth and long coherence time. We report on the /spl mu/-PL spectra of single GaAs/AlGaAs quantum dots grown on a (411)A surface of a GaAs substrate. We have observed sharp luminescence lines originating...
Summary form only given. Much attention has been recently focused on the investigation of photonic band gap (PBG) structures. In particular, it was demonstrated that unusual dispersion properties of such structures allow compact tunable optical delay lines to be implemented, parameters of short laser pulses to be controlled, and nonlinear-optical interactions to be phase-matched. We employ the finite...
Summary form only given. We report an absolute measurement of the optical frequency of a stabilized Nd:YAG laser by measuring the gap between its fundamental f/sub 1064/ and second harmonic 2f/sub 1064/ using a fs laser frequency comb which has been broadened in a silica microstructure fiber. To our knowledge, this is the first ever direct rf to optical frequency measurement using a single optical...
Summary form only given. Ultrashort pulse laser systems are finding increasing application in optical frequency metrology and nonlinear optics which require precise control over the pulse frequency and phase. We show the stabilization of the frequency, phase and repetition rate of an ultrashort pulse train to a Fabry-Perot reference cavity using a unique combination of actuators allowing for sufficient...
Summary form only given. In optical frequency metrology, it is often necessary to precisely bridge THz frequency gaps. Optical frequency combs (OFC) are one technique that have recently attracted interest. Key characteristics of OFCs include consistency of comb line spacing, center wavelength, and comb width. Previous OFCs have been constructed by placing an electro-optic modulator inside a high-finesse...
Summary form only given. Characterization of ultrashort light pulses is a primary concern of the researcher working with mode-locked lasers. Here we present an improved frequency domain phase measurement (FDPM). This configuration employs only linear passive filters with a nonlinear time integrating detector incorporated to measure a phase-dependent signal. In our setup we used a nonlinear detector...
Summary form only given. Two-beam coupling (TBC) with chirped pulses can be used to determine response times shorter than the chirped pulse duration. Here we explore the possibility of a direct determination of the electronic response time through measurements of two-beam coupling with pulses as short as 10 fs. We use fused silica as a model system. In numerical simulations we assume that the pulses...
Summary form only given. Recently B.A. Malomed theoretically predicted the existence of bound states of solitons in the dissipatively perturbed nonlinear Schrodinger equation. In this talk we report on the first experimental observation of bound soliton states in a passively mode locked fiber soliton laser. Multiple soliton operation is a generic feature of passively mode-locked fiber soliton lasers...
Summary form only given. Self-phase modulation (SPM) of optical pulses is the physical reason for a large variety of phenomena as optical solitons, spectral broadening and others. One of the most exciting applications is the utilization of SPM in a Kerr medium followed by propagation in a dispersive delay line for pulse compression. While the nonlinear propagation of pulses with the duration of many...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.