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.

Hyperspectral coherent anti-Stokes Raman scattering microscopy for in situ analysis of solid-state crystal polymorphs

(full pdf)

E.T. Garbacik, A.L. Fussell, S. Güres, J.P. Korterik, C. Otto, J.L. Herek, H.L. Offerhaus
SPIE Proceedings
vol. 8588 p 85880O-1 feb. 2, 2013
doi:10.1117/12.2004522

Hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy is quickly becoming a prominent imaging modality because of its many advantages over the traditional paradigm of multispectral CARS. In particular, recording a significant portion of the vibrational spectrum at each spatial pixel allows image-wide spectral analysis at much higher rates than can be achieved with spontaneous Raman. We recently developed a hyperspectral CARS method, the driving principle behind which is the fast acquisition and display of a hyperspectral datacube as a set of intuitive images wherein each material in a sample appears with a unique trio of colors. Here we use this system to image and analyze two types of polymorphic samples: the pseudopolymorphic hydration of theophylline, and the packing polymorphs of the sugar alcohol mannitol. In addition to these solid-state form modifications we have observed spectral variations of crystalline mannitol and diprophylline as functions of their orientations relative to the optical fields. We use that information to visualize the distributions of these compounds in a pharmaceutical solid oral dosage form. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE)