Comparison of coherent and spontaneous Raman microspectroscopies for noninvasive detection of single bacterial endospores
- Georgi I. Petrov‡,
- Rajan Arora‡,
- Vladislav V. Yakovlev‡,§,
- Xi Wang¶,
- Alexei V. Sokolov¶, and
- Marlan O. Scully§,¶,‖
- ‡Department of Physics, University of Wisconsin, P.O. Box. 413, Milwaukee, WI 53201;
- ¶Institute for Quantum Studies and Department of Physics, Texas A&M University, College Station, TX 77843; and
- ‖Applied Physics and Materials Science Group, Engineering Quad, Princeton University, Princeton, NJ 08544;
-
Contributed by Marlan O. Scully, March 8, 2007 (received for review January 29, 2007)
Abstract
Single bacterial spores were analyzed by using nonlinear Raman microspectroscopy based on coherent anti-Stokes Raman scattering (CARS). The Raman spectra were retrieved from CARS spectra and found to be in excellent agreement with conventionally collected Raman spectra. The phase retrieval method based on maximum entropy model revealed significant robustness to external noise. The direct comparison of signal amplitudes exhibited a factor of 100 stronger CARS signal, as compared with the Raman signal.
Footnotes
- §To whom correspondence may be addressed. E-mail: yakovlev{at}uwm.edu or scully{at}tamu.edu
-
Author contributions: G.I.P., V.V.Y., A.V.S., and M.O.S. designed research; G.I.P., R.A., V.V.Y., and X.W. performed research; G.I.P. and R.A. analyzed data; and G.I.P., V.V.Y., A.V.S., and M.O.S. wrote the paper.
-
The authors declare no conflict of interest.
- Abbreviations:
- CARS,
- coherent anti-Stokes Raman scattering;
- DPA,
- dipicolinic acid;
- CaDPA,
- calcium dipicolinate.
- © 2007 by The National Academy of Sciences of the USA
