Abstract

Recent technological advances in key components used in spectroscopic analysis have allowed the application of spectroscopy to samples smaller in size and concentrations than previously possible. About ten years ago Focal Plane Array (FPA) detectors were declassified for infrared spectroscopic use. The use of FPA’s eliminated the largest source of increased noise when measuring small samples via infrared microanalysis, the field aperture. Subsequently, the spatial resolution of infrared microscopic analysis was limited only by diffraction. The more recent application of point spread deconvolution mathematics to resultant FPA images has resulted in data collection to 2-3x better than the wavelength of light. Lastly, the incorporation of ultra-bright sources, such as synchrotron light sources and quantum cascade lasers (QCL) has provided further access to samples in water or are highly scattering. Tissue and art samples have been analyzed utilizing these new tools to demonstrate the ability to chemically characterize samples beyond the diffraction limit.

For Raman analysis, surface enhanced Raman spectroscopy (SERS) has become an important tool for facilitating the transition of spectroscopy to the biomedical and heritage communities. Current western blot and ELISA method analysis techniques have been shown to be inferior with respect to multiplexed analysis and sensitivity when compared to the newly implemented resonance SERS methods. Results will be shown demonstrating the benefit to using polymeric membrane based substrates to further enhance the SERS effect. A new SERS delivery device had also been developed for depositing silver and gold nanoparticles onto art samples to suppress fluorescence and greatly enhance the Raman signal. The nanoparticles are typically deposited in low picoliter quantities that would be nearly impossible to detect after the analysis was complete. Examples of the SERS analysis of documents and statues will be shown.

© 2015 Optical Society of America