The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Carles Serrat - One of the best experts on this subject based on the ideXlab platform.
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control of high order harmonics for attoscience using a Static Electric Field pattern
Physical Review A, 2011Co-Authors: Carles SerratAbstract:Quantum control in high-order-harmonic generation is considered theoretically by using a spatial distribution of Static Electric Fields along the propagation direction of the driving Field. It is shown that the trajectories of the electrons during its acceleration by the laser Field in the high-harmonics-generation process can be controlled by periodically distributed Static Electric Fields, which conveniently shape the driving laser Field during propagation. Applying this mechanism, a quasi-phase-matching scheme that leads to filtered enhanced high harmonics is achieved. The harmonics in the plateau region are enhanced due to periodical phase variations in the long quantum trajectories as a consequence of the faster change experienced by the intensity-dependent phase along the longer electron trajectories. This effect should be observed in all quasi-phase-matching schemes based on perturbation of the microscopic quantum phase. The richness of adding a Static-Electric-Field spatial pattern in the interaction region suggests a general scheme for feedback loop control in high-order-harmonic generation.
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all regions tunable high harmonic enhancement by a periodic Static Electric Field
Physical Review Letters, 2010Co-Authors: Carles Serrat, Jens BiegertAbstract:Simulations show that a Static Electric Field periodically distributed in space can be used to control the production of coherent light by high-order harmonic generation in a wide spectral range covering extremeultraviolet and soft x-ray radiation. The radiation yield is selectively enhanced due to symmetry breaking induced by a Static Electric Field on the interaction between the driving laser and the medium. The spectral position of the enhancement is tuned by varying the periodicity of the Static Electric Field which matches twice the coherence length of the harmonics in the desired region. We find that the Static Electric Field strength inducing enhancement decreases for shorter wavelengths and predict an increase of more than two orders of magnitude for harmonics in the water window spectral range with a Static Electric Field as weak as 1:12 MV=cm.
Anthony F Starace - One of the best experts on this subject based on the ideXlab platform.
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Static Electric Field induced polarization effects in harmonic generation
Physical Review Letters, 2000Co-Authors: Bogdan Borca, A V Flegel, M V Frolov, N L Manakov, D B Milosevic, Anthony F StaraceAbstract:: Two Static-Electric-Field-induced effects on harmonic generation are demonstrated analytically and numerically: elliptic dichroism (in which the harmonic yield is different for right and left elliptically polarized laser Fields) and elliptical polarization of harmonics produced by linearly polarized driving laser Fields. Both effects stem from interference of real and imaginary parts of the nonlinear atomic susceptibilities. Possibilities for experimentally measuring these effects are discussed.
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Static Electric Field effects on high harmonic generation
Physical Review A, 1996Co-Authors: Anthony F StaraceAbstract:High harmonic generation in the presence of a Static Electric Field is analyzed theoretically by an extension of the zero-range potential model treatment of Becker et al. [Phys. Rev. A 50, 1540 (1994)]. For ${\mathrm{H}}^{\ensuremath{-}}$ and a C${\mathrm{O}}_{2}$ laser of 5 \ifmmode\times\else\texttimes\fi{} ${10}^{10}$ W/${\mathrm{cm}}^{2}$ intensity, a Static Electric Field of 100 kV/cm is shown to produce a plateau from the 3rd to the 23rd harmonic in which neighboring even and odd harmonics are of comparable intensity. Furthermore, odd harmonics on the plateau are one or more orders of magnitude more intense than in the absence of the Static Electric Field. Dependence of emission rates on laser intensity and results for harmonic generation by Ar are also presented.
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Short-pulse detachment of H- in the presence of a Static Electric Field
Physical Review A, 1993Co-Authors: Q. Wang, Anthony F StaraceAbstract:Quantum interference erects occurring in photodetachment of H - in the presence of a uniform, Static Electric Field are shown theoretically to be controllable through use of short laser pulses having characteristic times comparable to photodetached electron reflection times. In particular, calculated cross sections for single-photon detachment by two laser pulses that are delayed and phase shifted relative to one another are shown to oscillate as a function of the relative phases of the laser pulses at fixed photodetached electron energy
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Short-pulse detachment of H{sup {minus}} in the presence of a Static Electric Field
Bulletin of the American Physical Society, 1993Co-Authors: Q. Wang, Anthony F StaraceAbstract:Detachment of negative ions in the presence of a Static Electric Field may lead to significant quantum interference effects (e.g., cross section oscillations) near threshold. We exhibit the dependence of such quantum interference effects on laser pulse length; specifically, when the laser pulse length is of the order of electron orbit times. We show furthermore that such interference effects may be controlled using two laser pulses, the second of which is time-delayed and phase shifted with respect to the first. Our calculations employ an analytically-known solution of the three-dimensional Schrodinger equation for an electron in both a laser and a Static Electric Field.
Jun Rekimoto - One of the best experts on this subject based on the ideXlab platform.
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mirage body motion and activity recognition using off body Static Electric Field sensing
International Conference on Embedded Networked Sensor Systems, 2013Co-Authors: Adiyan Mujibiya, Jun RekimotoAbstract:We present Mirage, a non body contact technique to infer the amount and type of body motion, gesture, and activity. This approach involves passive measurement of Static Electric Field of the environment flowing through sense electrode. This sensing method leverages Electric Field distortion by the presence of an intruder (e.g. human body). Mirage sensor has simple analog circuitry, supports ultra-low power operation, and requires no instrumentation to the user. We illustrate the utility of Mirage with a demonstration of real-time interactive applications including activity monitoring and games which allow the users to interact with a computer using body motion.
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mirage exploring interaction modalities using off body Static Electric Field sensing
User Interface Software and Technology, 2013Co-Authors: Adiyan Mujibiya, Jun RekimotoAbstract:Mirage proposes an effective non body contact technique to infer the amount and type of body motion, gesture, and activity. This approach involves passive measurement of Static Electric Field of the environment flowing through sense electrode. This sensing method leverages Electric Field distortion by the presence of an intruder (e.g. human body). Mirage sensor has simple analog circuitry and supports ultra-low power operation. It requires no instrumentation to the user, and can be configured as environmental, mobile, and peripheral-attached sensor. We report on a series of experiments with 10 participants showing robust activity and gesture recognition, as well as promising results for robust location classification and multiple user differentiation. To further illustrate the utility of our approach, we demonstrate real-time interactive applications including activity monitoring, and two games which allow the users to interact with a computer using body motion and gestures.
A Mysyrowicz - One of the best experts on this subject based on the ideXlab platform.
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strong enhancement of terahertz radiation from laser filaments in air by a Static Electric Field
Physical Review Letters, 2008Co-Authors: Aurelien Houard, B Prade, V T Tikhonchuk, A MysyrowiczAbstract:We observe a 3 order of magnitude enhancement of the terahertz energy radiated by a femtosecond pulse undergoing filamentation in air in the presence of a Static Electric Field. Measurements of terahertz pulse duration, spectrum, polarization, and radiation pattern elucidate the physical processes responsible for this radiation. A theoretical model explains the results and predicts another 3 orders of magnitude enhancement with a terawatt laser pulse.
Christiano J S De Matos - One of the best experts on this subject based on the ideXlab platform.
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quasi phase matched second harmonic generation in silicon nitride ring resonators controlled by Static Electric Field
Optics Express, 2013Co-Authors: Rafael E P De Oliveira, Christiano J S De MatosAbstract:Actively-controlled second harmonic generation in a silicon nitride ring resonator is proposed and simulated. The ring was designed to resonate at both pump and second harmonic wavelengths and quasi-phase-matched frequency conversion is induced by a periodic Static Electric Field generated by voltage applied to electrodes arranged along the ring. Nonlinear propagation simulations were undertaken and an efficiency of −21.67 dB was calculated for 60 mW of pump power at 1550 nm and for a 30V applied voltage, which compares favorably with demonstrated all-optical second harmonic generation in integrated microresonators. Transient effects were also evaluated. The proposed design can be exploited for the construction of electro-optical devices based on nonlinear effects in CMOS compatible circuits.
