Three-Dimensional Imaging of Chemical Bond Orientation in Liquid Crystals by Coherent Anti-Stokes Raman Scattering Microscopy

Oleg D Lavrentovich ,Brian G. Saar ,Heung-Shik Park 2,X. Sunney Xie ,Oleg D. Lavrentovich 2

Liquid Crystal Institute, Kent State University, Kent, OH 44242
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
2Liquid Crystal Institute and Chemical Physics Program, Kent State University, Kent, OH 44242

Liquid crystals are a class of industrially important materials whose optical properties make them useful particularly in display technology. Optical imaging of these materials provides information about their structure and physical properties. Coherent anti-Stokes Raman scattering (CARS) microscopy is used to provide three-dimensional chemical maps of liquid crystalline samples without the use of external labels. CARS is an optical imaging technique that derives contrast from Raman-active molecular vibrations in the sample. Compared to other three-dimensional imaging techniques, CARS offers the most rapid chemical characterization available without the use of external dyes or contrast agents. The use of CARS to image chemical and orientational order in liquid crystals is demonstrated using several different materials, and the limitations and benefits are discussed. (c) 2007 Optical Society of America

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