Product Code: ICA12_N301

Far-Field Nanoscale Thermal and Structure Imaging - Invited Presentation - 30 Minute Presentation
Authors:
Xiaoduan Tang, Department of Mechanical Engineering, Iowa State Univ.; -
Shen Xu, Department of Mechanical Engineering, Iowa State Univ.; -
Xinwei Wang, Department of Mechanical Engineering, Iowa State Univ.; Ames IA USA
Presented at ICALEO 2012

Micro/submicron particle induced near-field effect can focus the incident laser beam to a small region of tens of nanometers (nm). This phenomenon has been widely used in surface nanostructuring, particle-assisted surface nanostructure imaging under normal optical microscope, and surface enhanced Raman spectroscopy. To date, very little experiment has been reported on characterizing the temperature field induced by the extremely focused laser beam. In this work, we report on novel and pioneering experiment to measure the temperature of a region less than 100 nm size induced by near-field focusing. Raman spectroscopy is used for temperature measurement by observing the Raman frequency shift and peak width broadening. Great measures have been taken to rule out tiny Raman frequency drift in experiment to ensure high-accuracy temperature measurement with accuracy around 0.1 K. The effect of particle size and laser beam energy is systematically investigated. Most importantly, we achieve a resolution about 50 nm or smaller in probing the temperature distribution in space through far-field imaging. This represents the pioneering measurement about the near-field focused laser beam distribution in space and its induced thermal and structure fields.