Wayne S. Pelouch

Cornell University, Ithaca, New York, United States

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Publications (19)34.46 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: An investigation of the hot carrier relaxation in GaAs/(AlGa)As quantum wells and bulk GaAs in the high carrier density limit is presented. Using a time-resolved luminescence up-conversion technique with <or=80 fs temporal resolution, carrier temperatures are measured in the 100 fs to 2 ns range. The results show that hot carrier cooling in quantum wells becomes significantly slower than in the bulk for carrier densities greater than 2*1018 cm-3.
    Semiconductor Science and Technology 12/1998; 7(3B):B337. · 1.92 Impact Factor
  • Wayne S. Pelouch, L. A. Schlie
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    ABSTRACT: The ultrafast carrier dynamics in Hg0.6Cd0.4Te and Hg0.33Cd0.67Te are studied using a femtosecond optical parametric oscillator and the optical transmission‐correlation spectroscopy method. The band gaps of these materials are 2.85 μm (0.435 eV) and 1.47 μm (0.844 eV) at room temperature, respectively. The collective relaxation occurs within the 0.5 to 2 ps range and a fast scattering process is observed in the 150 to 200 fs range. Saturation effects are detected in the 0.844 eV band gap sample resulting in a transmission maxima near 2 ps in addition to the standard transmission peak at zero time delay. The magnitude of the saturable absorption is also measured as a function of carrier density and initial kinetic energy of the photoexcited carriers.
    Applied Physics Letters 03/1996; 68(10):1389-1391. · 3.52 Impact Factor
  • Wayne S. Pelouch, L. A. Schlie
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    ABSTRACT: The ultrafast carrier dynamics in GaSb are studied using optical transmission‐correlation spectroscopy with sub‐100‐fs pulses. The laser wavelength was tuned between 1.50 and 1.72 μm in order to differentiate between different scattering processes. The carriers scatter out of the initial distribution in 2–2.5 ps with a 200–350 fs component also observed. This faster component, usually attributed to phonon scattering, is observed below the assumed phonon emission threshold. When the laser is tuned above the intervalley scattering threshold a large fraction of the carriers rapidly scatter to the L valley. Saturation of the absorption is measured versus the pump power near the band edge.
    Applied Physics Letters 01/1995; 66:82-84. · 3.52 Impact Factor
  • Wayne S. Pelouch, L. A. Schlie
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    ABSTRACT: The ultrafast band‐edge carrier dynamics in In 0.65 Ga 0.35 As/GaAs are studied using a transmission correlation technique in the 77–300 K temperature range. The experiment is performed using a femtosecond optical parametric oscillator tunable in the 1.5–1.8 μm spectral range with sub‐100‐fs pulses. Rapid recovery (≤10 ps) of the nonlinear absorption is observed, suggesting an exceptionally high rate of recombination predominantly due to dislocations at the InGaAs/GaAs heterojunction. The phonon‐scattering time is experimentally identified and measured to be 200–400 fs.
    Applied Physics Letters 11/1994; · 3.52 Impact Factor
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    ABSTRACT: The recent development of femtosecond optical parametric oscillators has extended the wavelength range over which ultrafast lasers are available (visible to 3.5 micrometers has been demonstrated). The options in cavity configurations, phase matching, and nonlinear optical crystals used with a Ti:sapphire pump laser are discussed. Results of an OPO using the nonlinear crystal KTiOAs4, which is potentially tunable to 5 micrometers , are presented.
    Proc SPIE 05/1994;
  • Conference on Lasers and Electro-Optics; 05/1993
  • Source
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    ABSTRACT: The details concerning the resonator configuration, crystal parameters, and operating characteristics of high-repetition-rate and high-average-power broadly tunable femtosecond optical parametric oscillators are reviewed and discussed in some detail. We also report new results on an intracavity-doubled optical parametric oscillator with tunability from 580 to 657 nm in the visible and the first, to our knowledge, high-repetition-rate femtosecond optical parametric oscillator with the new nonlinear-optical crystal In:KTiOAsO4, which can potentially tune to 5.3 µm.
    Journal of the Optical Society of America B 01/1993; 10(11). · 2.21 Impact Factor
  • W S Pelouch, P E Powers, C L Tang
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    ABSTRACT: A self-mode-locked ring-cavity Ti:sapphire laser is described that is self-starting within milliseconds and completely unperturbed by the self-starting mechanism while mode locked. This technique makes use of a position-modulated mirror in an external cavity in which the cavity length and alignment are noncritical. Other benefits of the ring cavity over the linear cavity configuration are described.
    Optics Letters 11/1992; 17(22):1581-3. · 3.39 Impact Factor
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    ABSTRACT: The development of a Ti:sapphire-based femtosecond system capable of producing high repetition rate and high power output that is tunable from the near-ultraviolet to the mid- infrared is reported. This is achieved using the nonlinear optical processes of optical parametric oscillation and second-harmonic generation that results in sub-100 fs pulses and hundreds of mW of power across the full tuning range.
    Proc SPIE 11/1992;
  • [Show abstract] [Hide abstract]
    ABSTRACT: An investigation of hot carrier relaxation in GaAs/AlxGa1-xAs multiple quantum wells and bulk GaAs in the high carrier density limit is presented. Two techniques have been employed: luminescence upconversion with < 80 fs temporal resolution has been used to cover the range from 100 fs to 100 ps, and time-correlated single-photon counting to cover the range from 100 ps to 2 ns. Electron temperatures as a function of time were determined from the slope of the high energy tail of the time-resolved photoluminescence spectra. Our results show that hot electron cooling rates in the quantum wells begin to become significantly slower than that in the bulk when the photogenerated carrier density is above a critical value of approximately 2 X 1018 cm-3; the difference in cooling rates increases rapidly with increasing carrier density. The time constant characterizing the power loss of hot carriers is also determined and discussed. A comparison is made with previous publications to resolve the confusion concerning the difference in cooling rates between quasi-2D and 3D systems.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
    10/1992;
  • [Show abstract] [Hide abstract]
    ABSTRACT: An investigation of hot carrier relaxation in GaAs/AlxGa1-xAs multiple quantum wells and bulk GaAs in the high carrier density limit is presented. Two techniques have been employed: luminescence upconversion with < 80 fs temporal resolution has been used to cover the range from 100 fs to 100 ps, and time-correlated single-photon counting to cover the range from 100 ps to 2 ns. Electron temperatures as a function of time were determined from the slope of the high energy tail of the time-resolved photoluminescence spectra. Our results show that hot electron cooling rates in the quantum wells begin to become significantly slower than that in the bulk when the photogenerated carrier density is above a critical value of approximately 2 X 1018 cm-3; the difference in cooling rates increases rapidly with increasing carrier density. The time constant characterizing the power loss of hot carriers is also determined and discussed. A comparison is made with previous publications to resolve the confusion concerning the difference in cooling rates between quasi-2D and 3D systems.
    Proc SPIE 10/1992;
  • W S Pelouch, P E Powers, C L Tang
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    ABSTRACT: A broadly tunable femtosecond optical parametric oscillator (OPO) based on KTiOPO(4) that is externally pumped by a self-mode-locked Ti:sapphire laser is described. Continuous tuning is demonstrated from 1.22 to 1.37 microm in the signal branch and from 1.82 to 2.15 microm in the idler branch by using one set of OPO optics. The potential tuning range of the OPO is from 1.0 to 2.75 microm and requires three sets of mirrors and two crystals. Without prisms in the OPO cavity, 340 mW (475 mW) of chirped-pulse power is generated in the signal (idler) branch for 2.5 W of pump power. The total conversion efficiency as measured by the pump depletion is 55%. With prisms in the cavity, pulses of 135 fs are generated, which can be shortened to 75 fs by increasing the output coupling.
    Optics Letters 08/1992; 17(15):1070-2. · 3.39 Impact Factor
  • Source
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    ABSTRACT: An investigation of the hot-carrier relaxation in GaAs/(Al,Ga)As quantum wells and bulk GaAs in the high-carrier-density limit is presented. Using a time-resolved luminescence up-conversion technique with
    Physical review. B, Condensed matter 02/1992; 45(3):1450-1453. · 3.77 Impact Factor
  • 01/1992;
  • C. L. Tang, E. S. Wachman, W. S. Pelouch
    Conference on Lasers and Electro-Optics; 05/1991
  • E. S. Wachman, W. S. Pelouch, C. L. Tang
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    ABSTRACT: Continuous tuning of a CW femtosecond optical parametric oscillator (OPO) is demonstrated from 0.755-1.04 micron for the signal branch, and from 1.5-3.2 microns for the idler branch, covering most of the potential tuning range of the device. Transform-limited pulses under 120 fs in duration are found throughout the signal tuning, and idler pulsewidth measurements suggests pulses of less than 215 fs should be possible throughout the idler tuning. These results have been achieved using a new walkoff compensation scheme in the OPO. Preliminary results of transmission correlation measurements of carrier relaxation in InGaAs are presented using the parametric oscillator as a tunable excitation source.
    Journal of Applied Physics 01/1991; 70:1893-1895. · 2.21 Impact Factor
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    ABSTRACT: Not Available
    Nonlinear Optics: Materials, Phenomena and Devices, 1990. Digest. NLO '90.; 08/1990
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    ABSTRACT: The optical characteristics of the new nonlinear crystal lithium triborate (LiB 3 O 5 ) are evaluated for second‐harmonic generation (SHG) in the femtosecond regime. Using crystals grown in our laboratory, we demonstrate the use of LiB 3 O 5 for autocorrelation measurements of ultrashort optical pulses. We find that pulse widths down to 40 fs can be measured accurately with crystal thicknesses varying from 0.195 to 4.165 mm. The effect of crystal length on the autocorrelation shape is also investigated.
    Applied Physics Letters 08/1990; · 3.52 Impact Factor
  • W. R. Bosenberg, W. S. Pelouch, C. L. Tang
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    ABSTRACT: We report a novel, two‐crystal, walkoff‐compensated optical parametric oscillator design using β‐BaB 2 O 4 , which significantly improves the performance of the device. The oscillator is pumped at 354.7 nm and is tunable throughout 0.42–2.3 μm with overall conversion efficiencies as high as 32%. We also report on demonstration of linewidth narrowing in the same β‐BaB 2 O 4 oscillator, obtaining linewidths as narrow as 0.3 Å.
    Applied Physics Letters 12/1989; · 3.52 Impact Factor