Near-field Optics at fiber end-faces

• Main Authors: Li, Wen Kai, 李文凱
• Other Authors: Din Ping Tsai
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/46788617178554245220

碩士 === 國立中正大學 === 物理學系 === 85 === Abstract A tapping-mode scanning near-field optical microscope (SNOM) system with a bent optical fiber probe has been successfully developed to study the near-field optics at fiber end-faces. Topographic and near-field intensity image of fiber end-faces were obtained simultaneously.A brief and gentle etching process on fiber end-faces in a saturated solution of ammonium bifluoride (NH4F˙HF) was able to reveal the structure of fibers. The topographic features generated by different local chemistry areclosely related to local doping concentration and the distribution of refractive index. The correlation between fiber sturctures and their near- field intensity profiles of propagating modes can be acquired directly by this novel method. Micro lens produced by the chemical etch of fiber endface was studied as well. Variation of propagating near-field optical intensity distribution shows an increasing effective index for the existance of micro lens at fiber endface. Similarly, nano structure fabricated by e-beam lithography on fiber endface was studied in near- field, and showed the propagating near-field intensity was modulated by the existance of this nano structure.