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Alvin L Kwiram Symposium Electrical, Optical and Magnetic Properties of Organic and Hybrid Materials. Statistical Mechanical Modeling of Chromophore Interactions at High Concentration. Bruce H. Robinson Robert D. Nielsen Harrison Rommel. Outline.
Electrical, Optical and Magnetic Properties of Organic and Hybrid Materials
Bruce H. Robinson
Robert D. Nielsen
To generate a voltage across the material when shining light we need to have the molecules somewhat aligned or asymmetrically arranged.
We now proceed to explain
how and why this is so.
Explaining the Phenomenon:
• Steier, et al., “Polymeric waveguide prism based electro-optic beam deflector,” Opt. Eng., 40, 1217-22 (2001)
• Steier, et al., “Beam deflection with electro-optic polymer waveguide prism array,” Proc. SPIE, 3950, 108-116 (2000)
• Steier, et al., “Polymeric waveguide beam deflector for electro-optic switching,” Proc. SPIE, 4279, 37-44 (2001)
Steier, et al., IEEE mW & Guided Wave Lett. 9, 357 (1999)
1) Bandwidth limitation
2) Push-Pull modulation
to yield best effect?
The E field causes polarization and hyperpolarization
For the most part, consider effect on z, in molecule
Quantum Mechanical description
In the molecule, along z.
Net acentric ordering to give macroscopic Hyperpolarizability
The EO coefficient is proportional to molecular hyperpolarizability and the net order, which, we will see, is related to the intrinsic dipole moment.
Probability of being at a particular orientation q, is given by Boltzmann’s formula
We need to model the structures with simpler, classical rules. When considering many molecular interactions Q. M. too time consuming.
The strength of the interaction is relative to temperature, as a single parameter, x
Area under the two curves are the same.
Low Strength limit: F/3
Analytic mean field theory
MC simulations of dipole orientations
Piekara, A. (1939) Proc. R. Soc. London A 172, 360-381
There is always a maximum loading, which is very simply related to the dipole moment strength, and nearly independent of the poling field at typical fields
Propagation along controlling field
A 5 by 5 two dimensional array
Randomly oriented dipoles
If the energy is higher, compare Boltzmann Probability with a [0,1] random number, and keep if larger.
If the energy is lower, keep the move