Hollow, metal-lined waveguides used as gas sensors based on spontaneous Raman scattering are capable of large angular collection. The collection of light from a large solid angle implies the collection of a large number of waveguide modes. An accurate estimation of the propagation losses for these modes is required to predict the total collected Raman power. We report a theory/experimental comparison of the Raman power collected as a function of the solid angle and waveguide length. New theoretical observations are compared with previous theory appropriate only for low-order modes. A cutback experiment is demonstrated to verify the validity of either theory. The angular distribution of Raman light is measured using aluminum and silver-lined waveguides of varying lengths.
© 2012 Optical Society of America
Original Manuscript: September 28, 2011
Revised Manuscript: January 12, 2012
Manuscript Accepted: January 14, 2012
Published: April 16, 2012
Stephen Biedrzycki, Michael P. Buric, Joel Falk, and Steven D. Woodruff, "Angular output of hollow, metal-lined, waveguide Raman sensors," Appl. Opt. 51, 2023-2025 (2012)