| Autor: |
Galina Khitrova, S. G. Lee, Hyatt M. Gibbs, R. Jin, J. P. Sokoloff, Nasser Peyghambarian, P. A. Harten, C. L. Chuang, Ken E. Meissner, Rolf Binder, Francois Brown de Colstoun, Stephan W. Koch, Brian Fluegel |
| Rok vydání: |
1992 |
| Předmět: |
|
| Zdroj: |
SPIE Proceedings. |
| ISSN: |
0277-786X |
| DOI: |
10.1117/12.56721 |
| Popis: |
Ultrafast optical nonlinearities of semiconductor quantum wells and their application to high-speedswitching is discussed. Both GaAs-A1GaAs type-I and GaAs-AlAs type-Il quantum wells are considered.Optical Stark effect in these quantum wells and its use for fast photonic switching are covered. Application of optical Stark effect in demonstrating subpicosecond switching in a MQW directional coupler is discussed. 1 . INTRODUCTIONOptical nonlinearities in semiconductors may be classified into two categories: quasi-equilibrium ordynamic and transient or coherent nonlinearities. Quasi-equilibrium nonlinearities occur on relatively longtimescales where the created electrons and holes have sufficient time to interact among themselves andestablish Fermi-Dirac distributions within each band. Carrier generation can occur by many mechanisms,such as resonant laser excitation in the exciton resonance or above the bandgap, or by carrier generationthrough injection pumping. The resulting nonlinearities are called quasi-equilibrium nonlinearities since thecarriers responsible for the nonlinear material response are in "local" equilibrium among themselves. Thismeans that after their creation the carriers in the different bands have had sufficient time to interact andestablish a plasma temperature and a chemical potential, the two thermodynamic quantities needed to define aFermi distribution function for a given density. In quasi-equilibrium the dynamics of the electron-holepopulation, and not the excitation dynamics such as laser pulse duration etc., determines the dynamics of the |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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