Most materials absorb light, converting electromagnetic energy into thermal energy. The energy dissipation has traditionally been considered as undesirable for many usages of optical materials and needs to be minimized. The principal investigator approaches this problem from a new perspective: to make use of the dissipation in optical materials by converting it into useful functionalities. The project experimentally investigates the electromagnetic field confinement and enhancement in nanophotonic structures made of dissipative optical materials and explores their applications in molecule sensing. In parallel with the research component of the project, "Thinkingstorm" graduate- and undergraduate-student competitions on materials development and a lab immersion activity for high school students are carried out to enhance the education of critical thinking and problem solving skills.
Dissipative loss contributes directly to the distribution of both magnitude and phase of the electromagnetic field around a material. Photonic structures made of strongly absorbing materials may induce field redistribution in similar ways as plasmonic metal structures. The research component of this CAREER award explores new roles of imaginary part of material permittivity in controlling the light-matter interaction, especially at the interface between lossy/lossless materials. The principal investigator investigates electromagnetic field enhancement in lossy nanostructures using photochemical near-field imaging technique and experimentally measures the mode volume of the highly confined field. Electron energy loss spectroscopy is employed for studying the local photonic density of states. The understanding of these nanophotonic behaviors can lead to new forms of surface enhanced Raman spectroscopy. The research on composite materials over a large tunable range and on versatile dynamic control of material dissipation provides a solid base for new families of nanophotonic devices and changes the ways in which researchers control light, process optical materials, and design photonic structures.
