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Proceedings Paper

A Fabry-Perot etalon-based notch filter for background cleaning in Brillouin microscopy (Conference Presentation)

Paper Abstract

In Brillouin scattering imaging, rejection of background noise due to elastic scattering and reflections from optical components is crucial. This is because Brillouin signal is weak, and the signal frequency shift compared with source laser line is very small. Therefore the line of interest is very easy to be contaminated. Whereas physical blocking of undesired component in a dispersed spectrum is used, to filter out background optically provides better stability. Conventional optical filter techniques, such as dielectric-stack filters, holographic volume filters, Lyot fitlers etc. normally have a stopband-width (bandstop filter) or edge-width (edge filter) ranging from a few nanometers to tens of nanometers despite high rejection rate. They cannot be implemented in Brillouin imaging due to the small wavelength shift (< 1 pm). We report a Fabry-Perot etalon-based notch filter for background cleaning in Brillouin imaging. The notch filer takes advantage of multiple reflections of the light beam with a Fabry-Perot etalon to achieve high rejection with narrow bandwidth. The theoretical rejection rate is multiple time of the rejection of one reflection of the etalon. We demonstrated a laser line suppression of > 40 dB while with < 40% power loss with experiments. Width of the stopband at -30 dB rejection level is ~ 1 GHz. This method is not wavelength specific. One etalon may be implanted to a wide spectrum of laser wavelengths. Furthermore, it does not require heating as gaseous notch filters. Our method can also be implemented to Raman scattering, fluorescent imaging and other imaging techniques in which line of interest is close to the laser source.

Paper Details

Date Published: 27 April 2016
PDF: 1 pages
Proc. SPIE 9710, Optical Elastography and Tissue Biomechanics III, 97100H (27 April 2016); doi: 10.1117/12.2212629
Show Author Affiliations
Peng Shao, Wellman Ctr. for Photomedicine (United States)
Massachusetts General Hospital (United States)
Harvard Medical School (United States)
Sebastien Besner, Wellman Ctr. for Photomedicine (United States)
Massachusetts General Hospital (United States)
Harvard Medical School (United States)
Giuliano Scarcelli, Univ. of Maryland, College Park (United States)
Seok-Hyun Yun, Wellman Ctr. for Photomedicine (United States)
Massachusetts General Hospital (United States)
Harvard Medical School (United States)


Published in SPIE Proceedings Vol. 9710:
Optical Elastography and Tissue Biomechanics III
Kirill V. Larin; David D. Sampson, Editor(s)

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