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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 18, Iss. 11 — May. 24, 2010
  • pp: 11382–11395

Optimal algorithm for fluorescence suppression of modulated Raman spectroscopy

Michael Mazilu, Anna Chiara De Luca, Andrew Riches, C. Simon Herrington, and Kishan Dholakia  »View Author Affiliations

Optics Express, Vol. 18, Issue 11, pp. 11382-11395 (2010)

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Raman spectroscopy permits probing of the molecular and chemical properties of the analyzed sample. However, its applicability has been seriously limited to specific applications by the presence of a strong fluorescence background. In our recent paper [Anal. Chem. 82, 738 (2010)], we reported a new modulation method for separating Raman scattering from fluorescence. By continuously changing the excitation wavelength, we demonstrated that it is possible to continuously shift the Raman peaks while the fluorescence background remains essentially constant. In this way, our method allows separation of the modulated Raman peaks from the static fluorescence background with important advantages when compared to previous work using only two [Appl. Spectrosc. 46, 707 (1992)] or a few shifted excitation wavelengths [Opt. Express 16, 10975 (2008)]. The purpose of the present work is to demonstrate a significant improvement of the efficacy of the modulated method by using different processing algorithms. The merits of each algorithm (Standard Deviation analysis, Fourier Filtering, Least-Squares fitting and Principal Component Analysis) are discussed and the dependence of the modulated Raman signal on several parameters, such as the amplitude and the modulation rate of the Raman excitation wavelength, is analyzed. The results of both simulation and experimental data demonstrate that Principal Component Analysis is the best processing algorithm. It improves the signal-to-noise ratio in the treated Raman spectra, reducing required acquisition times. Additionally, this approach does not require any synchronization procedure, reduces user intervention and renders it suitable for real-time applications.

© 2010 Optical Society of America

OCIS Codes
(300.6380) Spectroscopy : Spectroscopy, modulation
(300.6450) Spectroscopy : Spectroscopy, Raman

ToC Category:

Original Manuscript: February 22, 2010
Revised Manuscript: April 30, 2010
Manuscript Accepted: May 6, 2010
Published: May 14, 2010

Virtual Issues
Vol. 5, Iss. 10 Virtual Journal for Biomedical Optics

Michael Mazilu, Anna Chiara De Luca, Andrew Riches, C. Simon Herrington, and Kishan Dholakia, "Optimal algorithm for fluorescence suppression of modulated Raman spectroscopy," Opt. Express 18, 11382-11395 (2010)

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