Associate Research Professor in the Department of Chemistry
Dr. Fischer’s research focuses on exploring novel nonlinear optical contrast mechanisms for molecular imaging. Nonlinear optical microscopes can provide non-invasive, high-resolution, 3-dimensional images even in highly scattering environments such as biological tissue.
Established contrast mechanisms, such as two-photon fluorescence or harmonic generation, can image a range of targets (such as autofluorescent markers or some connective tissue structure), but many of the most molecularly specific nonlinear interactions are harder to measure with power levels one might be willing to put on tissue. In order to use these previously inaccessible interactions as structural and molecular image contrasts we are developing ultrafast laser pulse shaping and pulse shape detection methods that dramatically enhance measurement sensitivity. Applications of these microscopy methods range from imaging biological tissue (mapping structure, endogenous tissue markers, or exogenous contrast agents) to characterization of nanomaterials (such as graphene and gold nanoparticles). The molecular contrast mechanisms we originally developed for biomedical imaging also provide pigment-specific signatures for paints used in historic artwork. Recently we have demonstrated that we can noninvasively image paint layers in historic paintings and we are currently developing microscopy techniques for use in art conservation and conservation science.
Samineni, Prathyush, et al. “Measurements of nonlinear refractive index in scattering media..” Optics Express, vol. 18, no. 12, June 2010, pp. 12727–35. Epmc, doi:10.1364/oe.18.012727. Full Text Open Access Copy
Warren, W. S., et al. “Nonlinear microscopy without fluorescence: Seeing the needle in the Haystack with Femtosecond pulse shaping.” Optics Infobase Conference Papers, Dec. 2009.
Fischer, M. C., and M. G. Raizen. “Experiments on quantum transport of ultra-cold atoms in optical potentials.” Lecture Notes in Physics, vol. 789, Dec. 2009, pp. 205–37. Scopus, doi:10.1007/978-3-642-03174-8_8. Full Text
Fischer, M. C., et al. “Enhancing two-color absorption, self-phase modulation and raman microscopy signatures in tissue with femtosecond laser pulse shaping.” Progress in Biomedical Optics and Imaging Proceedings of Spie, vol. 7183, June 2009. Scopus, doi:10.1117/12.816488. Full Text
Warren, W. S., et al. “New nonlinear signatures in spectroscopy and imaging.” Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series, Sept. 2008. Scopus, doi:10.1109/QELS.2008.4552901. Full Text
Warren, W. S., et al. “New nonlinear signatures in spectroscopy and imaging.” 2008 Conference on Quantum Electronics and Laser Science Conference on Lasers and Electro Optics, Cleo/Qels, Sept. 2008. Scopus, doi:10.1109/CLEO.2008.4552392. Full Text
Piletic, Ivan R., et al. “Rapid pulse shaping with homodyne detection for measuring nonlinear optical signals..” Optics Letters, vol. 33, no. 13, July 2008, pp. 1482–84. Epmc, doi:10.1364/ol.33.001482. Full Text
Fischer, Martin C., et al. “Simultaneous self-phase modulation and two-photon absorption measurement by a spectral homodyne Z-scan method..” Optics Express, vol. 16, no. 6, Mar. 2008, pp. 4192–205. Epmc, doi:10.1364/oe.16.004192. Full Text
Emami, Kiarash, et al. “Early changes of lung function and structure in an elastase model of emphysema--a hyperpolarized 3He MRI study..” Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 104, no. 3, Mar. 2008, pp. 773–86. Epmc, doi:10.1152/japplphysiol.00482.2007. Full Text
Fischer, Martin C., et al. “Self-phase modulation signatures of neuronal activity..” Optics Letters, vol. 33, no. 3, Feb. 2008, pp. 219–21. Epmc, doi:10.1364/ol.33.000219. Full Text