L. Michael Hayden

Associate Professor

Ph.D., University of California, Davis 1987

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Nonlinear Optical and Photorefractive Polymers Group Home Page

Research Interests

Nonlinear optical (NLO) polymers are promising new materials for use in devices such as optical modulators, wave-guide harmonic generators, and integrated optical switches. Devices such as these will be required in future photonic based communication, computing, and sensor systems. However, before the promise of these devices can be realized, the major stumbling block of material stability must be overcome.

We use NLO techniques such as second harmonic generation (SHG) and electro-optic (EO) modulation to probe the local environment and dynamics in macromolecular materials intended for use in photonic devices. Relaxation of the second order optical susceptibility is studied as a function of temperature and pressure. Activation energies and volumes associated with the relaxations are determined and used to identify the mechanism for the re-orientation of the NLO moiety. These structure-property results are used by chemists to synthesize new more stable materials. We also use SHG to study the effects of pressure on more general polymer characteristics such as the compressibility of the free volume and sub-Tg relaxations.

We have recently begun to apply molecular modeling techniques to the problems of polymer relaxations. Currently we are developing a program to use atomistic molecular dynamic simulations to model our nonlinear optical experiments.

The other major thrust of the laboratory is involved with photorefractive polymers. These new materials are interesting because of their potential application in optical signal processing, holographic storage, and all optical computing. We are currently measuring the photoconductivity, electro-optic coefficient, diffraction efficiency, and photorefractive two beam coupling gain in a variety of these new materials. In addition we are exploring guided wave applications in these materials.

Recent Publications

"Temperature Dependence of the Activation Volume in a Nonlinear Optical Polymer: Evidence for Chromophore Reorientation Induced by Sub-Tg Relaxations", S. J. Strutz and L. Michael Hayden, J. Polymer Sci. B: Polymer Phys. 36, 901 (1998).

"Effect of Pressure and Temperature on Chromophore Reorientation in a Side-Chain Nonlinear Optical Polymer", S. J. Strutz and L. Michael Hayden, (accepted) J. Polymer Sci. B: Polymer Phys. (1998).

"The Effect of Sub-Tg Relaxations on Chromophore Reorientation in Corona Poled Polymers", S. C. Brower and L. Michael Hayden, J. Polymer Sci. B: Polymer Phys. 36, 1013 (1998).

"Pressure Dependence of the Depoling Temperature in Nonlinear Optical Polymers", L. Michael Hayden, S. C. Brower, and S. J. Strutz, Macromolecules 30, 2734 (1997).

"Launching of Guided Modes in a Photorefractive Polymer Waveguide by Two Beam Coupling", D. Kokron, S. M. Evanko, and L. Michael Hayden, Opt. Lett. 20, 2297 (1995).

"Activation volume associated with the relaxation of the second order nonlinear optical susceptibility in a guest-host polymer," S. C. Brower, L. Michael Hayden, Appl. Phys. Lett. 63, 2059 (1993).