Quantum Optoelectronics

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Efficient Intersubband Scattering via Carrier-Carrier Interaction in Quantum Wells

Physical Review Letters 80:9 (1998) 1940-1943

Authors:

M Hartig, S Haacke, PE Selbmann, B Deveaud, RA Taylor, L Rota

Abstract:

Using femtosecond resonant luminescence, we have measured the intersubband scattering rate of electrons in wide GaAs quantum wells at very low excitation densities. Even when the spacing between the first two electron subbands is smaller than the LO phonon energy, we observe that intersubband scattering is a subpicosecond process, much faster than previously measured or anticipated. Our experimental results are in perfect agreement with Monte Carlo calculations, which show that carrier-carrier interaction is responsible for the ultrafast transitions. 漏 1998 The American Physical Society.

Ultrafast dynamics of excitonic scattering and gain in narrow ZnCdSe/ZnSe multiple quantum wells

Journal of Crystal Growth Elsevier 184 (1998) 645-649

Authors:

S Hess, RA Taylor, RA Adams, JF Ryan, RM Park

Ultrafast dynamics of excitonic scattering and gain in narrow ZnCdSe/ZnSe multiple quantum wells

J CRYST GROWTH 184 (1998) 645-649

Authors:

S Hess, RA Taylor, RA Adams, JF Ryan, RM Park

Abstract:

Time-resolved photoluminescence has been used to investigate the optical properties of a narrow 25 Angstrom Zn0.8Cd0.2Se/ZnSe multiple quantum well structure as a function of carrier density and temperature. At low temperatures, it is found that the luminescence is excitonic over all densities up to and above threshold. The underlying gain mechanism in cleaved 380 mu m cavities is excitonic in nature. In the low-density regime, the luminescence remains excitonic up to room temperature. (C) 1998 Elsevier Science B.V. All rights reserved.

Direct observation of the decay of a coherent polarization into an incoherent exciton population in quantum wells

Institute of Electrical and Electronics Engineers (IEEE) (1998) 225

Authors:

S Haacke, G Hayes, M Kauer, RA Taylor

Improving the signal-to-noise ratio of femtosecond luminescence upconversion by multichannel detection

Journal of the Optical Society of America B: Optical Physics 15:4 (1998) 1410-1417

Authors:

S Haacke, RA Taylor, I Bar-Joseph, MJSP Brasil, M Hartig, B Deveaud

Abstract:

We have improved the sensitivity and signal-to-noise ratio of a luminescence upconversion experiment, using a charge-coupled device (CCD) as the detector. We show experimentally and numerically that the bandwidth of a 1-mm-thick 尾-barium borate crystal is large enough to take full advantage of the multichannel capabilities of the CCD. The improvement is significant in a standard experiment with a single laser as well as in experiments with resonant excitation that use two synchronized femtosecond pulse sources at different wavelengths. The characteristics of the two-color scheme are discussed in detail. 漏 1998 Optical Society of America.