The Experts below are selected from a list of 19773 Experts worldwide ranked by ideXlab platform

Randy A. Bartels - One of the best experts on this subject based on the ideXlab platform.

  • time resolved coherent raman spectroscopy by High Speed Pump probe delay scanning
    Optics Letters, 2014
    Co-Authors: Scott R Domingue, David G Winters, Randy A. Bartels
    Abstract:

    Using a spinning window Pump-probe delay scanner, we demonstrate a means of acquiring time-resolved vibrational spectra at rates up to 700 Hz. The time-dependent phase shift accumulated by the probe pulse in the presence of a coherently vibrating sample gives rise to a Raman-induced frequency shifting readily detectable in a balanced detector. This rapid delay scanning system represents a 23-fold increase in averaging Speed and is >10× faster than state-of-the-art voice coil delay lines. These advancements make Pump-probe spectroscopy a more practical means of imaging complex media.

  • Rapid Birefringent Delay Scanning for Coherent Multiphoton Impulsive Raman Pump–Probe Spectroscopy
    IEEE Journal of Selected Topics in Quantum Electronics, 2012
    Co-Authors: Jesse W. Wilson, Randy A. Bartels
    Abstract:

    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.

  • rapid birefringent delay scanning for coherent multiphoton impulsive raman Pump probe spectroscopy
    IEEE Journal of Selected Topics in Quantum Electronics, 2012
    Co-Authors: Jesse W. Wilson, Randy A. Bartels
    Abstract:

    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.

  • Lighthouse ultrafast spectroscopy: High Speed scanning with a spinning birefringent delay crystal
    CLEO:2011 - Laser Applications to Photonic Applications, 2011
    Co-Authors: Jesse W. Wilson, Randy A. Bartels
    Abstract:

    A simple method for High Speed Pump probe spectroscopy that maintains interfer-ometric stability is presented. The lighthouse scanner demonstrates significant improvement ultrafast nonlinear spectroscopy signal to noise level by averaging large number of scans.

Jesse W. Wilson - One of the best experts on this subject based on the ideXlab platform.

  • Rapid Birefringent Delay Scanning for Coherent Multiphoton Impulsive Raman Pump–Probe Spectroscopy
    IEEE Journal of Selected Topics in Quantum Electronics, 2012
    Co-Authors: Jesse W. Wilson, Randy A. Bartels
    Abstract:

    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.

  • rapid birefringent delay scanning for coherent multiphoton impulsive raman Pump probe spectroscopy
    IEEE Journal of Selected Topics in Quantum Electronics, 2012
    Co-Authors: Jesse W. Wilson, Randy A. Bartels
    Abstract:

    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.

  • Lighthouse ultrafast spectroscopy: High Speed scanning with a spinning birefringent delay crystal
    CLEO:2011 - Laser Applications to Photonic Applications, 2011
    Co-Authors: Jesse W. Wilson, Randy A. Bartels
    Abstract:

    A simple method for High Speed Pump probe spectroscopy that maintains interfer-ometric stability is presented. The lighthouse scanner demonstrates significant improvement ultrafast nonlinear spectroscopy signal to noise level by averaging large number of scans.

Scott R Domingue - One of the best experts on this subject based on the ideXlab platform.

  • time resolved coherent raman spectroscopy by High Speed Pump probe delay scanning
    Optics Letters, 2014
    Co-Authors: Scott R Domingue, David G Winters, Randy A. Bartels
    Abstract:

    Using a spinning window Pump-probe delay scanner, we demonstrate a means of acquiring time-resolved vibrational spectra at rates up to 700 Hz. The time-dependent phase shift accumulated by the probe pulse in the presence of a coherently vibrating sample gives rise to a Raman-induced frequency shifting readily detectable in a balanced detector. This rapid delay scanning system represents a 23-fold increase in averaging Speed and is >10× faster than state-of-the-art voice coil delay lines. These advancements make Pump-probe spectroscopy a more practical means of imaging complex media.

M. Komárek - One of the best experts on this subject based on the ideXlab platform.

  • Influence of hydrophibization of impellers of centrifugal Pumps on their operating characteristics
    Thermal Engineering, 2016
    Co-Authors: A. V. Volkov, A. G. Parygin, A. V. Naumov, A. A. Vikhlyantsev, J. Šoukal, M. Sedlář, M. Komárek
    Abstract:

    This work presents experimental estimation results of changing of basic operation characteristics of a group of centrifugal Pumps covering a range of values of dimensionless power-Speed coefficient n _ s from 33 to 330 after hydrophobization of their impellers' surfaces. Hydrophobization of functional surfaces of impellers in all experiments was performed by formation of structures of organic covers by technology of MPEI NRU, which provides increasing of limiting wetting angle of surfaces to 120° and greater. Results of experimental researches of the influence of hydrophobization of impeller surfaces for High-Speed Pump ( n _ s = 330) on its characteristics is presented for the first time. Positive effect of applying hydrophobization technology to impeller surfaces in all the considered range of power-Speed coefficient was generalized and estimated. It was shown that hydrophobization of impeller surfaces of centrifugal Pumps provides increment to their efficiency factors within an acceptable operation range from 0.5 to 7.5%. Empiric function defining dependencies of efficiency factor increment of Pump on relative supply and power-Speed coefficient are suggested. Possibilities and estimation of extending acceptable operation range of a Pump depending on powerSpeed coefficient as a result of impeller surface hydrophobization are shown. Experimental data of comparative cavitation tests of High-Speed Pumps before and after hydrophobization of their impeller surfaces are generalized for the first time for considered range of power-Speed coefficient values. The influence of power-Speed coefficient on changing of critical net Pump suction head (critical positive suction pressure) is shown. Based on existing knowledge on Pumps, an attempt to validate experimentally obtained lows of changing of power and anticavitation features of centrifugal Pumps after hydrophobization of their impeller surfaces is made.

  • Influence of hydrophibization of impellers of centrifugal Pumps on their operating characteristics
    Thermal Engineering, 2016
    Co-Authors: A. V. Volkov, A. G. Parygin, A. V. Naumov, A. A. Vikhlyantsev, J. Šoukal, M. Sedlář, M. Komárek
    Abstract:

    This work presents experimental estimation results of changing of basic operation characteristics of a group of centrifugal Pumps covering a range of values of dimensionless power-Speed coefficient n _ s from 33 to 330 after hydrophobization of their impellers' surfaces. Hydrophobization of functional surfaces of impellers in all experiments was performed by formation of structures of organic covers by technology of MPEI NRU, which provides increasing of limiting wetting angle of surfaces to 120° and greater. Results of experimental researches of the influence of hydrophobization of impeller surfaces for High-Speed Pump ( n _ s = 330) on its characteristics is presented for the first time. Positive effect of applying hydrophobization technology to impeller surfaces in all the considered range of power-Speed coefficient was generalized and estimated. It was shown that hydrophobization of impeller surfaces of centrifugal Pumps provides increment to their efficiency factors within an acceptable operation range from 0.5 to 7.5%. Empiric function defining dependencies of efficiency factor increment of Pump on relative supply and power-Speed coefficient are suggested. Possibilities and estimation of extending acceptable operation range of a Pump depending on powerSpeed coefficient as a result of impeller surface hydrophobization are shown. Experimental data of comparative cavitation tests of High-Speed Pumps before and after hydrophobization of their impeller surfaces are generalized for the first time for considered range of power-Speed coefficient values. The influence of power-Speed coefficient on changing of critical net Pump suction head (critical positive suction pressure) is shown. Based on existing knowledge on Pumps, an attempt to validate experimentally obtained lows of changing of power and anticavitation features of centrifugal Pumps after hydrophobization of their impeller surfaces is made.

David G Winters - One of the best experts on this subject based on the ideXlab platform.

  • time resolved coherent raman spectroscopy by High Speed Pump probe delay scanning
    Optics Letters, 2014
    Co-Authors: Scott R Domingue, David G Winters, Randy A. Bartels
    Abstract:

    Using a spinning window Pump-probe delay scanner, we demonstrate a means of acquiring time-resolved vibrational spectra at rates up to 700 Hz. The time-dependent phase shift accumulated by the probe pulse in the presence of a coherently vibrating sample gives rise to a Raman-induced frequency shifting readily detectable in a balanced detector. This rapid delay scanning system represents a 23-fold increase in averaging Speed and is >10× faster than state-of-the-art voice coil delay lines. These advancements make Pump-probe spectroscopy a more practical means of imaging complex media.