# Presentation: 716858

## CAREER: Microscopic Study of Light Localization Hui Cao, Northwestern University,  DMR-0093949

- A surface plasmon represents a collective excitation of electrons. While its frequency is in the visible range, its wavelength can be as short as that of X-ray. Hence, surface plasmons play an important role in nano-optics. Using the near-field scanning optical microscopy, we have observed strong localization of surface plasmons in metal-dielectric nano-composites. The localization results in a buildup of huge electromagnetic field in the nano-scale. Such large local field can enhance various linear and nonlinear optical processes such as Raman or hyper-Raman scattering, wave mixing.

- Measured near-field intensity distribution in random metal-dielectric nano composites excited by an external light at =543nm.The red spots represent localization of surface plasmons. Both axes are in the unit of pixel (33 nm).

**Notes:**
A surface plasmon (SP) represents a collective excitation of electrons that is driven by external light. Its frequency is equal to that of incident light, but its wavelength can be as short as that of X-ray.  Therefore, surface plasmons play an important role in the development of nano-optics. We studied the surface plasmons in metal-dielectric nano-composites. 
Using a near-field scanning optical microscope, we measured the near-field intensity functions in semi-continuous metal-dielectric films. We observe strong localization of SP (the red spots in the figure). The spatial localization results in the buildup of a huge electromagnetic field in the nano-scale. Such large local field can enhance various linear and nonlinear optical process such as Raman or Hyper-Raman scattering, wave mixing, etc.

## CAREER: Microscopic Study of Light Localization Hui Cao, Northwestern University,  DMR-0093949

- One undergraduate Jaclyn Nesbitt, one graduate student Heeso Noh, two postodoc fellows Katyayani Seal and Alexey Yamilov have contributed to this work. Heeso Noh recently become a Ph.D. candidate. Alexey Yamilov joined the Department of Physics at University of Missouri as a junior faculty in September 2005.

**Societal Impact:**
- The ability to localize light in a microscopic region is very important to the development of nano-scale photonic devices.  Strong buildup of electromagnetic energy in the nano-scale has potential application in ultra-sensitive detection of single molecules.

**CAREER: Microscopic Study of Light Localization **Hui Cao, Northwestern University,  DMR-0093949

**Notes:**
One undergraduate Jaclyn Nesbitt, one graduate student Heeso Noh, two postodoc fellows Katyayani Seal and Alexey Yamilov have contributed to this work. Jaclyn learned how to fabricate nano-composites, Heeso mastered the techniques of near-field scanning optical microscopy. Alexey Yamilov joined the Department of Physics at University of Missouri as a junior faculty in September 2005. 

The ability to localize light in a microscopic region is very important to the development of nano-scale photonic devices.  Strong buildup of electromagnetic energy in the nano-scale enhances various linear and nonlinear optical processes that have been used for sensors,  and enables ultra-sensitive detection of single molecules in biomedical sensing.