Biomedical applications of adaptive optical interferometry
Adaptive interferometry uses a self-adaptive beam mixer instead of a passive beam mixer as conventional interferometry does. A photorefractive quantum well device acting as an adaptive beam mixer in a two-wave mixing geometry stabilizes the interferometric phase in the far field. Advantages of adaptive interferometry are explored in two kinds of biomedicine: adaptive optical coherence reflectometry for biomedical imaging and adaptive optical bio-compact (BioCD) disk for biosensing. Adaptive Optical Coherent Domain Reflectometry (OCDR) used adaptive ultrafast pulse mixing as the coherent gate for OCDR for the first time. Studied homodyne signals from the adaptive pulse-mixing effect, as well as the sensitivity and noise by both experiments and simulations. Demonstrated the addition ability of laser based ultrasound detection of this technique. Adaptive BioCD is an adaptive interferometric technique for biomolecule sensing and fast surface topography with atomic microscope grade accuracy. The technique directly detects the optical thickness of biomolecule patterns immobilized on a flat surface. The surface is scanned in a spinning-disk design, like reading a CD, which provides fast readout and huge surface area for space-divided multi-analyte immunoassay detection by measuring the optical thickness change due to local reactions. Immunoassay experiments successfully detected binding between antibodies and immobilized antigens in a 2-analyte immunoassay with high specificity and without observable cross-reactivity. The system achieved sensitivity in optical thickness of less than one tenth of a monolayer of protein.
Nolte, Purdue University.
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