Development and applications of integrated nonlinear imaging tools

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This research program works to develop new and improved microscopy and spectroscopy tools that are based on nonlinear optical processes, and which, when integrated in concert into a cohesive microscopy platform, are brought to bear on discovering new structures and properties of a wide range of materials systems, including condensed biomolecular assemblies, drugs/pharmaceuticals, and geological materials. ***A particular type of imaging that uses intense laser pulses is known as nonlinear optical microscopy, and this ever-expanding framework includes such techniques as two-photon excitation fluorescence, second-harmonic generation (SHG), third-harmonic generation, four-wave-mixing, and coherent anti-Stokes Raman scattering (CARS). Despite its applicability for imaging and characterizing a wide range of materials systems, at present this technology is fully entrenched as a "biomedical imaging" tool. A guiding principle of this research program is to investigate and demonstrate the potential of this powerful tool to answer important questions in other disciplines such as biomaterials, drug forensics, the geosciences, and paleobiology. Over the past grant cycle, we have developed a uniquely agile multimodal CARS microscopy setup, and have begun using it to characterize such material systems. We will continue the technical development of this tool and expand the scope of its application. We will first target the identification and characterization of various supercontinuum-generating technologies—predominately those based on microstructured optical fibres—to yield inexpensive sources for CARS. Such sources will improve on our existing world's-best hyperspectral scan-range capabilities. We will concurrently work to add polarization-sensitive excitation and detection schemes both to the SHG and CARS modalities, providing unique insight into the presence and orientation of important biomolecular assemblies. These tools will then be used for the hyperspectroscopic characterization of important materials systems such as economically important protist aquaculture and powdered drug/pharmaceutical samples. The rapid and label-free imaging capabilities of multimodal CARS microscopy will provide unique chemical identification and three-dimensional assaying of these samples, thus expanding our scope of knowledge and demonstrating the potential of the technique for novel applications beyond biomedical imaging.***This program builds on CRC- and CFI-supported infrastructure that is unique to the region, with NSERC-supported HQP and operating funds, to undertake technically-challenging and world-class experimental photonics research. In combination with a wide-range of local and international collaborations, the program offers an excellent venue for the training of highly qualified students and researchers at all levels of education.