Instrumentation for Ultrahigh Resolution Temporal and Spatial Studies of Materials and Devices

摘要

This contract provided support for the procurement of equipment to build and operate improved near-field scanning optical microscopes (NSOMs). Improved scanning stages were constructed, and a scheme for high speed scanning developed based on distance regulation with tuning forks. In this scheme the phase of the drive to the fork is monitored with a digital phase-locked loop, which allows very rapid adjustment of the fork position in response to damping changes that occur as the fork and optical fiber tip are scanned in close proximity to a surface. In addition, new excitation and detection schemes were developed, which have allowed us to pioneer the use of nonlinear NSOM for the study of ferroelectric and ferromagnetic domains, and the crystal structure of surfaces.