Background-free optical fiber probe for Raman spectroscopy

12 Novembre 2012 , Rédigé par JW Publié dans #Recent research work

Optical fiber probes are generating a large interest for portable Raman spectrometers. However, the use of conventional fibers is severely limited by the high luminescence background generated in the silica, which complicates the signal processing and/or the probe implementation.
We solve this issue in a recent article published in Optics Letters by using a new type of hollow core photonic crystal fiber probe for Raman spectroscopy and endoscopy. Thanks to a design based on a large pitch Kagome lattice, the transmission range spans over 150nm, enabling both the excitation and Raman beams to be counter-propagating through the same fiber.
Compared to earlier work, our approach combines several novel key features: (i) the very simple optical configuration, (ii) the two orders of magnitude reduction in silica background noise, and (iii) the large spectral bandwidth for Raman shifts.