CARS microscopy in a wide-field geometry with nanosecond pulses

Abstract

We demonstrate coherent anti-Stokes Raman scattering (CARS) microscopy in a wide-field geometry and discuss the reasons why this approach is capable of becoming a complementary method to confocal scanning CARS microscopy. By means of nanosecond laser pulses and a non-confocal excitation geometry, the CARS signal is generated over a sample area of approximately 50 μm in diameter. As an example, we recorded images of oil drops within finely sliced sunflower seeds by tuning the laser frequency to the strong Raman transition of linoleic acid around 2870 cm-1. Meaningful images with spectral selectivity could already be recorded using only a few nanosecond pulses. Copyright © 2006 John Wiley & Sons, Ltd.