The precise characterization of the ultrafast optical response of metals and metallic nanostructures has remained an experimental challenge. We probe the few-femtosecond electronic dephasing of a local surface plasmon polariton excitation using symmetry-selective second-harmonic (SH) Rayleigh scattering of a nanoscopic conical gold tip as an individual plasmonic nanostructure. The full reconstruction of the optical response function of the plasmon excitation with phase and amplitude without any model assumptions is demonstrated from the analysis of the two-dimensional spectrogram obtained by simultaneous time- and frequency-domain SH measurements, using interferometric frequency resolved optical gating. The measured dephasing time of T(2) = 18 +/- 5 fs indicates the plasmon damping is dominated by nonradiative decay, consistent with a Drude-Sommerfeld dielectric response for gold. Even for the nominally homogeneous localized plasmon response, deviations are observed from the ideal harmonic oscillator phase behavior, which may reflect the underlying inhomogeneous electronic response with its different scattering channels. The presented technique is generally applicable for the reconstruction of the plasmon dynamics of complex nanostructures: information that cannot be obtained by conventional dark-field scattering.
Coincident electron-ion detection after photoionization in a "reaction microscope" is a very powerful tool to study atomic and molecular dynamics. However, the implementation of this tool in the field of attosecond science has so far been rather limited, due to the lack of high repetition rate laser sources capable of delivering few-cycle pulses with sufficient energy per pulse. In this article, the development of a Non-collinear Optical Parametric Amplifier (NOPA) capable of delivering Carrier-Envelope Phase (CEP) stable pulses with sub-6 fs duration and pulse energies in the few-µJ range is presented. The potential of combining the high repetition rate source and a reaction microscope operating at this high frequency is demonstrated in a proof-of-principle experiment on strong field ionization of Ar atoms.
This paper represents a systematic investigation of detection shot noise in carrier-envelope phase (CEP) stabilization. Numerical simulations are conducted to calculate the influence of shot noise in laser oscillators. These results are compared with experimental results for Ti:sapphire lasers. It is found that shot noise imposes a limitation for obtaining sub-100 mrad CEP jitters. Careful interferometer design is necessary to push this limit toward 10 mrad. In contrast to oscillator stabilization, shot noise appears to play a much more restrictive role in amplifier stabilization. Using spectral interferometry together with spectral broadening in sapphire, it already appears practically challenging to reach sub-100 mrad jitters. Adaption of the optical nonlinearity in the broadening step appears key to further improvements of the CEP jitter of amplified systems. We believe that these improvements open a perspective for currently unfeasible applications of CEP stabilized pulses. Moreover, our considerations can be easily adapted to CEP stabilization of other laser types beyond Ti:sapphire.applications is the measurement of the carrier-envelope phase (CEP) of ultrashort laser pulses, which is the subject of this paper. In this article we systematically investigate the role of shot noise on different CEP measurement and stabilization schemes for oscillator and amplifier systems. We provide simulations to quantify the light level dependence of the shot noise induced phase jitter, and we show that the role of shot noise is often underestimated. Furthermore we discuss published experimental results of different CEP-stabilization schemes in the context of these simulations.
Carrier-envelope phaseThe ability to control the phase of the carrier wave of ultrashort pulses with respect to its envelope [8-10] is not only relevant for the field of extreme nonlinear optics and attosecond science [11,12], but is also of great importance for frequency comb-based metrology [13][14][15]. In the past different schemes for the measurement of the CEP of ultrashort laser pulses have been proposed. The first attempt to measure the slippage rate of the CEP, i.e., the carrier-envelope offset (CEO) frequency f CEO , relied on the nonlinear C
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