Multimode metal-lined capillaries for Raman collection and sensing

Abstract

Reflective metal-lined capillary waveguides are useful for laser-power delivery or for collecting scattered light in sensing applications. We theoretically examine the multimode propagation of polarized light in largediameter, metallized, capillary waveguides using a new perturbation technique valid for all waveguide modes. This modeling permits prediction of the collection efficiency of Raman or fluorescent light produced in the waveguide at all angles. These theoretical results are supported by measuring the intensity and angular distribution of collected scattered gas-Raman Stokes power. © 2010 Optical Society of America