Fluidic and Polymeric Integration and Functionalization of Optical Microresonators

Citation

Maune, Brett Michael (2006) Fluidic and Polymeric Integration and Functionalization of Optical Microresonators. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/2746-3104. https://resolver.caltech.edu/CaltechETD:etd-11222005-163249

Abstract

Optical resonators are structures that spatially confine and temporally store light. The use of such resonators continues to permeate throughout society as improvements in their design and fabrication qualify them to fulfill an ever-increasing array of technological and scientific applications. Traditionally, resonators have primarily been used in lasers and as filters, and more recently have been utilized in other areas including chemical sensing, spontaneous emission modulation, and quantum electrodynamics experiments. In many of these applications, the functionalities of the resonators are solely derived from the geometry and material composition of the resonators themselves. The central theme of this thesis is the investigation of further increasing a resonator's functionality through its integration with fluidic and polymeric materials.

The thesis begins with an investigation of integrating silicon ring resonators with electro-optic polymer and liquid crystal in an effort to tune the resonators' resonant wavelengths. Although the electro-optic polymer efforts are a failure, we are able to electrically tune the rings' resonances using electrodes and the reorientation of liquid crystal surrounding the resonators. We then take the knowledge and experience acquired from these experiments and pursue the functionalization of photonic crystal laser resonators, a relatively new class of microresonators constructed from a thin slab of InGaAsP quantum well material with a periodic array of holes etched through the slab. To this end, we first infiltrate the porous resonators with liquid crystal and construct liquid crystal cells around the devices. We are then able to tune the lasing wavelengths by reorienting the liquid crystal with a voltage applied across the cell. Next, we devise a new photonic crystal cavity designed to optimally interact with infiltrated birefringent materials, by supporting two orthogonally polarized high-Q modes. Again, we infiltrate the cavity with liquid crystal, but this time optically control the liquid crystal orientation with a photoaddressable polymer film. By doing so we are able to realize a fundamentally new laser tuning method by reversibly Q-switching a resonator's lasing mode between the two cavity modes and thereby control the laser's emission wavelength and polarization. The successful fluidic and polymeric integration with optical resonators presented in this thesis demonstrates some of the possible synergies that can be obtained with such integration and suggests that further enhancements in resonator functionality is possible.

Thesis Files