Title :
Terahertz probes of transient conducting and insulating phases in quasi-2D electron-hole gases
Author :
Kaindl, R.A. ; Hägele, D. ; Carnahan, M.A. ; Lövenich, R. ; Chemla, D.S.
Author_Institution :
Dept. of Phys., California Univ., Berkeley, CA, USA
fDate :
27 Sept.-1 Oct. 2004
Abstract :
We employ ultrafast terahertz (THz) pulses to study the dynamical interplay of optically-induced excitons and unbound electron-hole pairs in GaAs/AlGaAs quantum wells. A distinct low-energy oscillator appears upon resonant excitation of heavy-hole excitons, linked to transitions between their internal degrees of freedom. Time-resolving changes in the THz conductivity, we can observe dynamical transitions between conducting and insulating phases as excitons form or ionize on ultrashort timescales.
Keywords :
III-V semiconductors; aluminium compounds; electrical conductivity transitions; excitons; gallium arsenide; high-speed optical techniques; semiconductor quantum wells; two-dimensional electron gas; two-dimensional hole gas; GaAs-AlGaAs; GaAs-AlGaAs quantum wells; THz conductivity; degrees of freedom; dynamical transition; heavy hole excitons; low energy oscillator; optically induced excitons; quasi2D electron-hole gases; resonant excitation; terahertz probes; transient conducting phase; transient insulating phase; ultrafast THz pulse; ultrafast terahertz pulse; unbound electron-hole pairs; Conductivity; Excitons; Gallium arsenide; Gas insulation; Gases; Optical pulses; Oscillators; Probes; Resonance; Ultrafast optics;
Conference_Titel :
Infrared and Millimeter Waves, 2004 and 12th International Conference on Terahertz Electronics, 2004. Conference Digest of the 2004 Joint 29th International Conference on
Print_ISBN :
0-7803-8490-3
DOI :
10.1109/ICIMW.2004.1422184
