Welcome to our research group


Prof. Ralph A. Höpfel +

+ deceased  May  1997


The continuous goal of our group is the research on ultrafast physical processes in solids (mostly semiconductors) and their quantum nanostructures. The experimental tools are femtosecond laser pulses. The group works with the state-of-the-art Ti:sapphire and dye lasers (pulses well below 100 fs in the spectral range of 350 nm to 1000 nm).

fire   Current research activities:

 Coherent excitations in semiconductors  Generation of THz radiation from fs pulses  Femtosecond luminescence in semiconductors  Ultrafast processes in nanostructures  Imaging through turbid media

    Please contact the group members:

Wolfgang Fischler
e-mail: wolfgang.fischler@uibk.ac.at
phone: +43 512 507 6332
Nancy E. Hecker
e-mail: nancy.hecker@uibk.ac.at
phone: +43 512 507 6312
Hannes Kostner
e-mail: hannes.kostner@uibk.ac.at
phone: +43 512 507 6332
Christina Messner
e-mail: christina.messner@uibk.ac.at
phone: +43 512 507 6312
Andreas Zimmermann
e-mail: andreas.zimmermann@uibk.ac.at
phone: +43 512 507 6312

Former group members:
Rudolf Bratschitsch
Institut für Festkörperelektronik, TU Wien
e-mail: rbrat@fkeserver.fke.tuwien.ac.at
Reinhard Gabl

Siemens AG, Munic, Germany 
e-mail: reinhard.gabl@mchp.siemens.de
Rosana Rodrigues-Herzog

University of Basel 
e-mail: rodrigues@ubaclu.unibas.ch
Christian Teissl
University of Innsbruck
e-mail: christian.teissl@uibk.ac.at


Short selection of recent publications:

"Enhanced light emission from a single quantum well located near a metal coated surface"
N. Hecker, R.A. Höpfel, and N. Sawaki, accepted to Physica E (1998)

"Coherent generation of tunable, narrow-band THz radiation by optical rectification of femtosecond pulse trains"
C. Messner, M. Sailer, H. Kostner, and R.A. Höpfel, Appl. Phys. B 64, 619 (1997).

"Anomalous reduction in the energy loss of electrons in p-GaAs" R. Rodrigues-Herzog, N. Hecker, M. Sailer, R.A. Höpfel, U. Hohenester, P. Kocevar, Phys. Rev. B (rapid communications, 15 March 1997).

"Generation of ultrashort far-infrared pulses tunable around 5 THz" M. Sailer, C. Messner, R.A. Höpfel, Tech. Digest of "European Quantum Electronics Conference 1996", p. 85.

"Ultrafast reflectivity changes in GaAs Schottky diodes" W. Fischler, P. Buchberger, G. Zandler, R.A. Höpfel, Appl. Phys. Lett. 68, 2778 - 2780 (1996).

"Intraband inversion due to ultrashort carrier liefetimes in proton bombarded InP" R.A. Höpfel, Ch. Teissl, K.F. Lamprecht, L. Rota, Physical Rev. B 53, 12581-12584 (1996).

"Ultrafast energy loss of electrons in p-GaAs" R. Rodrigues-Herzog, M. Sailer, N. Hecker, R.A. Höpfel, N. Nintunze, M.A. Osman, Appl. Phys. Lett. 67, 264-266 (1995).

"Intersubband relaxation of heavy-hole excitons in GaAs quantum wells" R.A. Höpfel, R. Rodrigues, Y. Iimura, N. Yasui, Y. Segawa, Y. Aoyagi, S. Goodnick, Phys. Rev. B47, 10943-10946 (1993).

"Spectral narrowing of ultrashort laser pulses by self-phase-modulation in optical fibers" M. Oberthaler, R.A. Höpfel, Appl. Phys. Lett. 63, 1017-1019 (1993).

"Enhancement of second harmonic generation in metal islands close to a conducting surface" D. Steinmüller, R.A. Höpfel, A. Leitner, F.R. Aussenegg, Appl. Phys. A57, 261-265 (1993).

"Microcavity effects in the luminescence of GaAs microcrystals" S. Juen, J. Baldauf, K. Überbacher, K.F. Lamprecht, R. Tessadri, R.A. Höpfel, Appl. Phys. Lett. 62, 1958-1960 (1993).

"Femtosecond relaxation of localized plasma excitations in Ag islands" D. Steinmüller, R.A. Höpfel, E. Gornik, A. Leitner, F.R. Aussenegg, Phys. Rev. Lett. 68, 389 - 392 (1992).

   Highlights of the history:

"Time-resolved measurement of tunneling and energy relaxation of hot electrons in GaAs/AlGaAs double quantum well structures" N. Sawaki, R.A. Höpfel, E. Gornik, H. Kano, Appl. Phys. Lett. 55, 1996 (1989).

"Subpicosecond photoluminescence from radiation-damaged Ga0.47In0.53As" R.A. Höpfel, N. Sawaki, E. Wintner, Appl. Phys. Lett. 55, 460 (1989).

"Negative photoconductivity due to carrier drag in GaAs/AlGaAs quantum wells" S. Juen, R.A. Höpfel, A.C. Gossard, Appl. Phys. Lett. 54, 2097-2099 (1989).

"Electron-Hole Scattering in GaAs Quantum Wells" R.A. Höpfel, J. Shah, P.A. Wolff, A.C. Gossard, Phys. Rev. B 37, 6941 (1988).

"Negative Absolute Mobility of Minority Electrons in GaAs" R.A. Höpfel, J. Shah, P.A. Wolff, A.C. Gossard, Phys. Rev. Lett. 56, 2736-2939 (1986).

"Nonequilibrium Electron-Hole Plasma in GaAs Quantum Wells" R.A. Höpfel, J. Shah, A.C. Gossard, Phys. Rev. Lett. 56, 765-768 (1986).

    Upcoming Conferences:
CLEO/IQEC '98 CLEO/IQEC'98  San Francisco, USA May 3-8, 1998
ULTRAFAST PHENOMENA '98 ULTRAFAST PHENOMENA '98 Garmisch-Partenkirchen, Germany July 12-17, 1998
24th International conference on the physics of semiconductors ICPS 24 Jerusalem, Israel August 2-7,  1998
Conference On Lasers and  Electro -Optics /Europe and European Quantum Electronics Conference, 1998 CLEO/Europe, EQEC  Glasgow, Scotland, UK  September 15-17,  1998 


   Lectures of the Institute of Experimental physics, University of Innsbruck, spring, summer 1998

   Physikkolloqium: Invited guest talks WS 1997/98


Last change: 07 April 1998
Page maintained by: Christina Messner