Michael Wiggins

Tunable Polymer Lens

A new type of solid-state variable focal length lens is described. It is based on shape changes in an elastomeric membrane driven by compression of a reservoir of a polymer gel. A novel fabrication process based on individual lens components allows for customization of lens power based on the desired application. The lens shape as a function of applied compressive strain is measured using direct surface profile measurements. The focal length of a solid state lens was reversibly changed by a factor of 1.9. Calculated back focal lengths of the lens were consistent with experimental measurements.

A widely tunable refractive index in a nanolayered photonic material

A class of composite polymer films is described in which the refractive index can be varied by simple mechanical forces. The films are comprised of 1024 alternating layers of an elastomer and a glassy polymer. When the layer spacing is much less than the wavelength of the probe light, these materials behave as effective medium composites. The layer thickness of the elastomer component and thus the effective index of the composite can be varied by compressing the composite.

Optical limiting properties of nonlinear multimode waveguide arrays

An experimental investigation of the transmission of multimode capillary waveguide arrays containing a liquid nonlinear absorber shows an enhanced nonlinear response relative to that found in a single waveguide and to the same length of bulk material. Comparison of the nonlinear response of arrays with different pitch to diameter (d/Lambda) ratios confirm that both the intensity distribution within an individual waveguide and coupling between the elements of the array influence the overall nonlinear response.

Bio-inspired optical polymers

Nanolayered polymer films were used to construct materials whose properties mimic bio-optic systems found in nature. The nanolayered structures have the unique ability to control the index gradient profile in three dimensions.

Characterization of dye-doped polymer films for polymer 1D photonic crystals

The incorporation of a nonlinear dye into a nanolayered polymer structure has the ability to greatly enhance the nonlinear transmission of the dye. Several characteristics of the nanolayered structured were studied to optimize the effect.

Nonlinear transmission of 1D photonic crystal polymers

Transmission from a strongly nonlinear material incorporated into monolithic and nanolayered polymer thin films are compared. When the laser wavelength approaches the bandgap, the nanolayered films transmit less than monoliths as excitation fluence is increased.

Variable refractive index polymeric nanolayered films

A new class of polymer films comprised of alternating elastomeric and glassy polymer nanolayers is described. Applying pressure to the composite can reversibly vary the refractive index. The mechanism for the index change was investigated by reflectance measurements, which were also used to assess the modulus of the elastomeric nanolayer.