Fabrication of optical fibre pencil shaped tips for nano objective imaging using home made tapering technique

Abstract

A method is developed to produce chemically etched optical fibre tips for small and nano objective imaging with valuable properties such as large transmission and no lateral light leaks. Tips are coated with a dielectric material like Al, Cr, etc., that is refraction-index approximately matched to silica. First small objective imaging of latex nanospheres with the smallest optical aperture tips confirms their ability to reach subwavelength optical resolution. In addition, thanks to their high transmission and collection efficiencies as well as their natural achromatism. Probing optical properties of materials and optical characterisation of molecular defects at the nanometre scale has been inaccessible until recently owing to the diffraction limit of light. With the invention of nanometric fibre optic tip by the help of chemical etching and tapering technique, resolution at the 50 ± 100 nm level using visible or near infrared light is now practical. The unique capability of fibre optic probe to simultaneously measure surface topography and local optoelectronic properties, thereby eliminating the need to perform cross correlation analysis on results obtained using different techniques, is particularly useful in this area. The noticeable improvement of tapering technique was observed here.