The Experts below are selected from a list of 7272 Experts worldwide ranked by ideXlab platform
Randy A. Bartels - One of the best experts on this subject based on the ideXlab platform.
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Rapid Birefringent Delay Scanning for Coherent Multiphoton Impulsive Raman Pump–Probe Spectroscopy
IEEE Journal of Selected Topics in Quantum Electronics, 2012Co-Authors: Jesse W. Wilson, Randy A. BartelsAbstract:Ultrafast Pump-Probe Spectroscopy experiments often measure weak nonlinear interactions, which produce very low signal levels. Averaging is usually required to increase the SNR to obtain the system response from the stochastic noise background. It has been recognized that averaging rapidly acquired Pump-Probe scans yields performance that is often superior to long averaging at each delay point, particularly in the presence of flicker (1/f) noise. We have demonstrated a particularly simple method for high-speed Pump-Probe delay scanning that maintains interferometric stability between the two pulses. This technique nicknamed lighthouse scanning uses a spinning birefringent crystal to rapidly vary the time separation between a Pump and Probe pulse pair. This scanning technique will be valuable for most Pump-Probe Spectroscopy techniques. We demonstrate the technique in a six-wave mixing process of coherence-modulated third-harmonic generation (CM-THG). CM-THG is a recently demonstrated method for separating bulk and interface contributions to vibrational coherences, but the high nonlinearity of the experiment leads to low signal levels. Rapid scan averaging with the lighthouse scanner improves signal to noise by at least an order of magnitude, greatly expanding the number of systems that can be studied with this technique.
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rapid birefringent delay scanning for coherent multiphoton impulsive raman Pump Probe Spectroscopy
IEEE Journal of Selected Topics in Quantum Electronics, 2012Co-Authors: Jesse W. Wilson, Randy A. BartelsAbstract:Ultrafast Pump-Probe Spectroscopy experiments often measure weak nonlinear interactions, which produce very low signal levels. Averaging is usually required to increase the SNR to obtain the system response from the stochastic noise background. It has been recognized that averaging rapidly acquired Pump-Probe scans yields performance that is often superior to long averaging at each delay point, particularly in the presence of flicker (1/f) noise. We have demonstrated a particularly simple method for high-speed Pump-Probe delay scanning that maintains interferometric stability between the two pulses. This technique nicknamed lighthouse scanning uses a spinning birefringent crystal to rapidly vary the time separation between a Pump and Probe pulse pair. This scanning technique will be valuable for most Pump-Probe Spectroscopy techniques. We demonstrate the technique in a six-wave mixing process of coherence-modulated third-harmonic generation (CM-THG). CM-THG is a recently demonstrated method for separating bulk and interface contributions to vibrational coherences, but the high nonlinearity of the experiment leads to low signal levels. Rapid scan averaging with the lighthouse scanner improves signal to noise by at least an order of magnitude, greatly expanding the number of systems that can be studied with this technique.
Jesse W. Wilson - One of the best experts on this subject based on the ideXlab platform.
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Rapid Birefringent Delay Scanning for Coherent Multiphoton Impulsive Raman Pump–Probe Spectroscopy
IEEE Journal of Selected Topics in Quantum Electronics, 2012Co-Authors: Jesse W. Wilson, Randy A. BartelsAbstract:Ultrafast Pump-Probe Spectroscopy experiments often measure weak nonlinear interactions, which produce very low signal levels. Averaging is usually required to increase the SNR to obtain the system response from the stochastic noise background. It has been recognized that averaging rapidly acquired Pump-Probe scans yields performance that is often superior to long averaging at each delay point, particularly in the presence of flicker (1/f) noise. We have demonstrated a particularly simple method for high-speed Pump-Probe delay scanning that maintains interferometric stability between the two pulses. This technique nicknamed lighthouse scanning uses a spinning birefringent crystal to rapidly vary the time separation between a Pump and Probe pulse pair. This scanning technique will be valuable for most Pump-Probe Spectroscopy techniques. We demonstrate the technique in a six-wave mixing process of coherence-modulated third-harmonic generation (CM-THG). CM-THG is a recently demonstrated method for separating bulk and interface contributions to vibrational coherences, but the high nonlinearity of the experiment leads to low signal levels. Rapid scan averaging with the lighthouse scanner improves signal to noise by at least an order of magnitude, greatly expanding the number of systems that can be studied with this technique.
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rapid birefringent delay scanning for coherent multiphoton impulsive raman Pump Probe Spectroscopy
IEEE Journal of Selected Topics in Quantum Electronics, 2012Co-Authors: Jesse W. Wilson, Randy A. BartelsAbstract:Ultrafast Pump-Probe Spectroscopy experiments often measure weak nonlinear interactions, which produce very low signal levels. Averaging is usually required to increase the SNR to obtain the system response from the stochastic noise background. It has been recognized that averaging rapidly acquired Pump-Probe scans yields performance that is often superior to long averaging at each delay point, particularly in the presence of flicker (1/f) noise. We have demonstrated a particularly simple method for high-speed Pump-Probe delay scanning that maintains interferometric stability between the two pulses. This technique nicknamed lighthouse scanning uses a spinning birefringent crystal to rapidly vary the time separation between a Pump and Probe pulse pair. This scanning technique will be valuable for most Pump-Probe Spectroscopy techniques. We demonstrate the technique in a six-wave mixing process of coherence-modulated third-harmonic generation (CM-THG). CM-THG is a recently demonstrated method for separating bulk and interface contributions to vibrational coherences, but the high nonlinearity of the experiment leads to low signal levels. Rapid scan averaging with the lighthouse scanner improves signal to noise by at least an order of magnitude, greatly expanding the number of systems that can be studied with this technique.
Dario Polli - One of the best experts on this subject based on the ideXlab platform.
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Broadband Fourier-Transform Pump-Probe Spectroscopy and Stimulated Raman Scattering Microscopy at Megahertz Modulation Frequencies
Light Energy and the Environment, 2016Co-Authors: Fabrizio Preda, Giulio Cerullo, Aurelio Oriana, Julien Réhault, Sandro De Silvestri, Dario PolliAbstract:We introduce a common-path birefringent interferometer to perform Fourier-transform Spectroscopy combined with lock-in detection at 20-MHz frequency. We apply it for broadband Pump-Probe Spectroscopy and stimulated Raman scattering microscopy.
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broadband Pump Probe Spectroscopy at 20 mhz modulation frequency
Optics Letters, 2016Co-Authors: Fabrizio Preda, Vikas Kumar, Francesco Crisafi, Diana Gisell Figueroa Del Valle, G Cerullo, Dario PolliAbstract:We introduce an innovative high-sensitivity broadband Pump-Probe Spectroscopy system, based on Fourier-transform detection, operating at 20-MHz modulation frequency. A common-mode interferometer employing birefringent wedges creates two phase-locked delayed replicas of the broadband Probe pulse, interfering at a single photodetector. A single-channel lock-in amplifier demodulates the interferogram, whose Fourier transform provides the differential transmission spectrum. Our approach combines broad spectral coverage with high sensitivity, due to high-frequency modulation and detection. We demonstrate its performances by measuring two-dimensional differential transmission maps of a carbon nanotubes sample, simultaneously acquiring the signal over the entire 950–1350 nm range with 2.7·10−6 rms noise over 1.5 s integration time.
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Tracking charge transfer in carbon nanotube networks with chirped Pump-Probe Spectroscopy
CLEO: 2011 - Laser Science to Photonic Applications, 2011Co-Authors: Daniele Brida, Dario Polli, Jared Crochet, Tobias Hertel, Giulio Cerullo, Guglielmo LanzaniAbstract:We observed an ultrafast charge generation and transfer in a carbon nanotube network by a novel Pump-Probe Spectroscopy that makes use of a broadband and positively chirped Pump and transform-limited Probe pulses.
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Evidence for electron correlation in (6,5) carbon nanotubes from Pump-Probe Spectroscopy with broadband pulses
Springer Series in Chemical Physics, 2009Co-Authors: Larry Lüer, Jared Crochet, Dario Polli, Tobias Hertel, Guglielmo LanzaniAbstract:Pump-Probe Spectroscopy with 10 fs time resolution is performed on (6,5) carbon nanotubes. We decompose the spectra into contributions from the first and second exciton,demonstrating their electronic correlation.
Gagik G. Gurzadyan - One of the best experts on this subject based on the ideXlab platform.
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Femtosecond Pump–Probe Spectroscopy of graphene oxide in water
Journal of Physics D, 2014Co-Authors: Jingzhi Shang, Lin Ma, Jiewei Li, Wei Ai, Ting Yu, Gagik G. GurzadyanAbstract:Transient absorption properties of aqueous graphene oxide (GO) have been studied by use of femtosecond Pump?Probe Spectroscopy. Excited state absorption and photobleaching are observed in the wide spectral range. The observed fast three lifetime components are attributed to the absorption of upper excited states and localized states, which is confirmed by both laser induced absorption and transmission kinetics. The longest time component is assigned to the lowest excited state of GO, which mainly originates from the sp2 domains. With the increase of the excitation power, two-quantum absorption occurs, which results in an additional rise-time component of the observed transients.
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singlet fission in rubrene single crystal direct observation by femtosecond Pump Probe Spectroscopy
Physical Chemistry Chemical Physics, 2012Co-Authors: Keke Zhang, Christian Kloc, Maria Elisabeth Michelbeyerle, Gagik G. GurzadyanAbstract:The excited state dynamics of rubrene in solution and in the single crystal were studied by femtosecond Pump–Probe Spectroscopy under various excitation conditions. Singlet fission was demonstrated to play a predominant role in the excited state relaxation of the rubrene crystal in contrast to rubrene in solution. Upon 500 nm excitation, triplet excitons form on the picosecond time scale via fission from the lowest excited singlet state. Upon 250 nm excitation, fission from upper excited singlet states is observed within 200 fs.
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Singlet fission in rubrene single crystal: direct observation by femtosecond Pump–Probe Spectroscopy
Physical Chemistry Chemical Physics, 2012Co-Authors: Lin Ma, Keke Zhang, Christian Kloc, Maria Elisabeth Michel-beyerle, Gagik G. GurzadyanAbstract:The excited state dynamics of rubrene in solution and in the single crystal were studied by femtosecond Pump–Probe Spectroscopy under various excitation conditions. Singlet fission was demonstrated to play a predominant role in the excited state relaxation of the rubrene crystal in contrast to rubrene in solution. Upon 500 nm excitation, triplet excitons form on the picosecond time scale via fission from the lowest excited singlet state. Upon 250 nm excitation, fission from upper excited singlet states is observed within 200 fs.
Tobias Hertel - One of the best experts on this subject based on the ideXlab platform.
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Tracking charge transfer in carbon nanotube networks with chirped Pump-Probe Spectroscopy
CLEO: 2011 - Laser Science to Photonic Applications, 2011Co-Authors: Daniele Brida, Dario Polli, Jared Crochet, Tobias Hertel, Giulio Cerullo, Guglielmo LanzaniAbstract:We observed an ultrafast charge generation and transfer in a carbon nanotube network by a novel Pump-Probe Spectroscopy that makes use of a broadband and positively chirped Pump and transform-limited Probe pulses.
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Evidence for electron correlation in (6,5) carbon nanotubes from Pump-Probe Spectroscopy with broadband pulses
Springer Series in Chemical Physics, 2009Co-Authors: Larry Lüer, Jared Crochet, Dario Polli, Tobias Hertel, Guglielmo LanzaniAbstract:Pump-Probe Spectroscopy with 10 fs time resolution is performed on (6,5) carbon nanotubes. We decompose the spectra into contributions from the first and second exciton,demonstrating their electronic correlation.
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Pump Probe Spectroscopy of exciton dynamics in 6 5 carbon nanotubes
Journal of Physical Chemistry C, 2007Co-Authors: Jared Crochet, Michael S Arnold, Mark C Hersam, Hendrik Ulbricht, Daniel E Resasco, Tobias HertelAbstract:We investigate exciton dynamics in isopycnically enriched (6,5) nanotube-DNA suspensions using femtosecond time-resolved Pump−Probe Spectroscopy. The ground state recovery is characterized by a t-0.45 ± 0.03 power law behavior, indicative of a one-dimensional diffusion-limited reaction that is tentatively attributed to subdiffusive trapping of dark excitons. Spectral transients of bright singlet excitons within the E11 and E22 manifolds exhibit a photobleach (PB) and a photoabsorption (PA) signal of similar strength. The PA is blue-shifted with respect to the PB-signal by 7.5 meV and is attributed to a transition from the dark singlet exciton to a + state within the two exciton E11 manifold.
