Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter at the nanoscale. We do this by exploring ways to shape light and its environment. It's what we call active and passive control. Our current focus is on the interaction of light with biomolecules and nanostructures. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.
We participate in the EU-COST actions MP1102: Coherent Raman microscopy (MicroCor) and CM1202: Supramolecular photocatalytic water splitting (PERSPECT-H2O)


Computational optimization of phase shaped CARS

(full pdf)

Alexander C.W. van Rhijn, Aliakbar Jafarpour, Jennifer L. Herek, and Herman L. Offerhaus
Multiphoton Microscopy in the Biomedical Sciences XII
Vol. 8226, 82262B january 22, 2012

We explore strategies for optimizing selectivity, specificity, and sensitivity in broadband CARS by precalculating pulse shapes using an evolutionary algorithm. We show the possibility of selective excitation of a single constituent in a test case of a mixture of five resonant compounds. The obtainable contrast ratio for a test case of PMMA in a mixture of five resonant compounds is predicted to be 2000:1, and is related the uniqueness of the complex vibrational response of the compound of interest compared to that of the durrounding molecules.
Furthermore we investigate how the effects of homodyne mixing in the focal volume affect the obtainable contrast ratio and how noise affects the optimization. We also show preliminary results of experimental optimization of the CARS signal from PMMA microspheres, resulting in high contrast imaging, free of non-resonant background signal.
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