Hollow-optical fiber probe for confocal Raman endoscopy

Abstract

A confocal Raman probe based on a silver hollow optical fiber is developed to apply in remote optical biopsy via a micro-endoscope. The probe consists of a single hollow optical fiber delivering both the excitation and the Raman scattered light, and a confocal end unit attached at the distal end of the fiber. We demonstrate a high spatial resolution remote Raman measurement with the present probe. The measured spectrum shows a depth-resolution of below 0.15 μm. In addition, we propose a ball lens coupled miniature high-resolution Raman probe and show that it operates as well as the confocal probe.