Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.


Vibrational phase contrast CARS microscopy for quantitative analysis

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M. Jurna, E.T. Garbacik, J.P. Korterik, C. Otto, J.L. Herek, H.L. Offerhaus
SPIE Proceedings
Vol. 7569 p. 75690F-1 February 26, 2010

In biological samples the resonant CARS signal of less abundant constituents can be overwhelmed by the non-resonant background, preventing detection of those molecules. We demonstrate a method to obtain the phase of the oscillators in the focal volume that allows discrimination of those hidden molecules. The phase is measured with respect to the local excitation fields using a cascaded phase-preserving chain. It is measured point-by-point and takes into account refractive index changes in the sample, phase curvature over the field-of-view andinterferometric instabilities. The detection of the phase of the vibrational motion can be regarded as a vibrational extension of the linear (refractive index) phase contrast microscopy introduced by Zernike around 1933.
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