Accession Number : ADA329794

Title :   Nonlinear Optical Response of Confined Excitons in Molecular and Semiconductor Nanostructures.

Descriptive Note : Final rept. 1 Jul 94-31 Jul 97,

Corporate Author : ROCHESTER UNIV NY DEPT OF CHEMISTRY

Personal Author(s) : Mukamel, Shaul

PDF Url : ADA329794

Report Date : 29 AUG 1997

Pagination or Media Count : 6

Abstract : The nonlinear optical response of Semiconductor Quantum Wells, Organic Superlattices and Conjugated Polyenes was calculated using collective electronic coordinates, which represent the joint dynamics of electron-hole pairs. The use of femtosecond four-wave mixing spectroscopy to probe the nature of electronic States and Exciton and free-carrier interactions in these systems was explored. The formation and dynamics of quasiparticles involving electrons dressed by nuclear deformations in conjugated polymers was studied. The Si natures of charged solitons, neutral solitons, polarons and bipolarons in the resonant and off-resonant optical susceptibilities of conjugated polymers were calculated using the Pariser-Parr-Pople (PPP) model. The optical response was obtained by solving equations of motion for the reduced single-electron density matrix, derived using the time dependent Hartree-Fock (TDHF) approximation. The approach relates the optical Signals directly to the dynamics of charges and bond orders (electronic coherences) induced by the radiation field and uses only ground-state information, thus avoiding the explicit calculation of excited states. A Density-Matrix-Electronic-Oscillator representation was employed for calculating the third order nonlinar A optical response of semiconductor quantum dots in the limits of weak and strong exciton confinement. The nonlocal electrodynamics of arrays of quantum dots was treated exactly using Green function techniques. The research program included the development of software which uses the newly developed algorithms in the design of new optical materials.

Descriptors :   *QUANTUM ELECTRONICS, *HARTREE FOCK APPROXIMATION, OPTICAL PROPERTIES, EQUATIONS OF MOTION, SPECTROSCOPY, REACTION TIME, HOLES(ELECTRON DEFICIENCIES), SEMICONDUCTORS, FREE ELECTRONS, NONLINEAR SYSTEMS, MOLECULAR STRUCTURE, GREENS FUNCTIONS, SOLITONS, EXCITONS.

Subject Categories : Numerical Mathematics
      Crystallography
      Quantum Theory and Relativity

Distribution Statement : APPROVED FOR PUBLIC RELEASE