Spatial & Temporal Resolution in Near-Field Optical Microscopy

摘要

This project elucidated and examined the unique science behind the spectral and temporal contrast of near field scanning optical microscopy, illuminated the technology this enabled, and considered the limits of simultaneous position, time and spectral resolution. Specifically, (1) High- resolution, quantitative measurements of excess carrier lifetime in silicon were acquired in a novel, all-optical technique. The contrast in the images was modeled and is of interest since the resolution is significantly shorter than the carrier diffusion length. (2) a Ti-sapphire laser has been constructed and modified to decrease pump power requirements so that measurements can be made before the carriers diffuse from under the probe. Novel electron-hole droplet effects are expected. (3) Spectroscopic nano-Raman images were acquired for the first time. The Raman data illustrated interesting manifestations of a near- field in comparisons with far-field spectroscopy. (4) The first and most thorough studies of the optical and thermal properties of near-field scanning optical microscope probes gave insights which led to the development of a new generation of high throughput probes. Other results reflect instrumentation advances: (5) A new constant linear motion system useful for NSOM or other probe microscope coarse approach. (6) A new, low cost force feedback system. (7) A nanometer-resolution, kHz bandwidth, millimeter range position sensor.