Tip Optimization for Near-Field Scanning Optical Microscopy by Laser-Heated Pulling

Abstract

The ability to manufacture reproducible and low-cost probe tips is critical for the improvement of near-field scanning optical microscopy as both the resolution and efficiency of the apparatus depend on the tip's geometrical configuration. The purpose of this project is to investigate tip fabrication and bending with Sutter Instrument P-2000 micropipette puller in order to produce tips with aperture sizes less than 100nm and cone angles larger than 40°. Advancements in NSOM technology are of special interest to the Biological and Chemical Sciences as it has applications as diverse as chromosome mapping and single molecule detection. Successful results were obtained along the region corresponding to heat, velocity, delay, and pull values of 190, 20, 126 and 70 respectively. The best configuration obtained was a 52.3 nm aperture with a 52.16° cone angle. Also the bending process was improved by proposing a three spot heating procedure.