Confocal Raman microscopy in the visible and near infrared range for maximum flexibility of sample analysis

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This proposal is to fund major repairs and upgrades of a combined dispersive and FT-Raman microscopy system with both visible and near infrared (NIR) excitation wavelengths, which was purchased with funds from CFI and a previous NSERC RTI in 2010-2011 and is currently installed in Cerruti's laboratory in the department of Materials Engineering at McGill University. The combination of an FT-Raman spectrometer with NIR excitation and a dispersive confocal Raman microscope with visible excitation allows analyzing a wide variety of samples, including samples that fluoresce when excited with visible radiation, such as biological and organometallic samples. Raman microscopy conventionally uses visible radiation due to the larger intensity of signals collected in this frequency range. Excitation with NIR radiation prevents the development of fluorescence but has low signal-to-noise ratio. FT-Raman spectroscopy with NIR excitation was developed to solve this problem: the NIR radiation collected from the sample goes through an interferometer before hitting the detector, thus allowing the collection of a whole spectrum in less than a second. By accumulating hundreds of spectra the signal-to-noise ratio is dramatically increased. The combination of an FT-Raman with NIR excitation and a dispersive Raman confocal microscope with visible excitation, allowing to collect spectral maps at these different wavelengths with micrometer resolution, is unique in Canada and very rare elsewhere in the world. Such a unique combination has been widely used in the past 10 years, supporting the NSERC-funded programs of 20 researchers and their HQPs. Although the system has been maintained regularly, currently both one of the visible lasers (532 nm) and the detector of the FT-Raman, used to detect NIR radiation, are down; also, both the dispersive and the FT-Raman system absolutely require a workstation and software upgrade for smoother operation, as they are currently running on an obsolete computer that is the only one that can still support the software installed in 2010. The lack of a functional NIR detector and of the 532 nm laser are severely delaying (or completely preventing) the research from the four co-applicants and the 12 major users of the instrument, and the progress of their 59 HQPs belonging to 9 different departments. The proposed repairs will make this unique system fully operational again and will improve its performance thanks to the software and workstation upgrade. HQPs accessing it will get full hands-on experience, gaining valuable skills that will be applicable in fields including biological material analysis, biotechnology, development of materials for energy and environment, biomaterials, quality control, etc. The diverse team of co-applicants and the many EDI-related actions the PIs implement for HQP recruitment and training ensure that a diverse range of HQPs will have access to the instrument and feel always welcome to use it.