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.


High-resolution narrowband CARS spectroscopy in the spectral fingerprint region

(full pdf)

P. F. Chimento, M. Jurna, H. S. P. Bouwmans, E. T. Garbacik, L. Hartsuiker, C. Otto, J. L. Herek, H. L. Offerhaus
Journal of Raman Spectroscopy
Vol. 40 Issue 9 P 1229-1233, September 2009

Coherent anti-Stokes Raman scattering (CARS) spectroscopy is an important technique for spectroscopy and chemically selective microscopy, but wider implementation requires dedicated versatile tunable sources. We describe an optical parametric oscillator (OPO) based on a magnesium oxide-doped periodically poled lithium niobate crystal, with a novel variable output coupler, used as a tunable coherent light source. The OPO's signal wavelength ranges from 880 to 1040 nm and its idler wavelength from 1090 to 1350 nm.

We use this OPO to demonstrate high-resolution narrowband CARS spectroscopy on bulk polystyrene from 900 to 3600 cm-1, covering a large part of the molecular fingerprint region. Recording vibrational spectra using narrowband CARS spectroscopy has several advantages over spontaneous Raman spectroscopy, which we discuss. We isolate the resonant part of the CARS spectrum and compare it to the spontaneous Raman spectrum of polystyrene using the maximum entropy method of phase retrieval; we find them to be in extremely good agreement. © 2009 John Wiley & Sons, Ltd.
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