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.

 

Time-resolved hyper-Rayleigh scattering: Measuring first hyperpolarizabilities beta of fluorescent molecules


Noordman OFJ, vanHulst NF
CHEMICAL PHYSICS LETTERS
vol 253 issue 1-2: p145-p150 APR 26 1996

Time-resolved hyper-Rayleigh scattering experiments using a femtosecond mode-locked Ti-sapphire laser are presented. The technique is capable of discriminating between hyper-Rayleigh scattered light and fluorescent emission induced by multiphoton absorption with a time resolution of 80 ps. Measurements o­n the non-fluorescent organic molecules crystal violet and calix- [4]arene demonstrate that the technique can measure first hyperpolarizabilities beta consistent with experiments using a Q-switched Nd:YAG laser. The first hyperpolarizability beta of a fluorescent molecule, which is often overestimated when using a nanosecond laser system, can be corrected for long-term fluorescence using the time-resolved technique as is demonstrated for the octupolar molecule 1,3,5-tris[(4- pyridyl)ethynyl]benzene.
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