Tip-Enhanced Infrared Nanospectroscopy via Molecular Expansion Force Detection
Event details
| Date | 15.01.2014 |
| Hour | 14:15 |
| Speaker |
Prof. Mikhail Belkin, University of Texas, Austin, TX (USA) Bio: Dr. Belkin received PhD in Physics in from the University of California at Berkeley in 2004. In 2004-2008 he did his postdoctoral work in Prof. Federico Capasso group in the School of Engineering and Applied Sciences. In Fall 2008, he joined the faculty of the Electrical and Computer Engineering Department of the University of Texas at Austin. His research interests include investigating and utilizing giant nonlinear optical responses in metamaterials, quantum cascade lasers, and other engineered and/or low-dimensional structures, sub-wavelength resolution microscopy in mid- and far-infrared, THz radiation sources, and plasmonic devices. Dr. Belkin’s recent awards include the NSF CAREER Award, the DARPA Young Faculty Award, the AFOSR Young Investigator Award, and the Norman Hackerman Advanced Research Program Award for Early Career Investigators from the state of Texas. He has authored or co-authored over 100 journal and conference papers. For more details, please visit webpage at UT Austin. |
| Location | |
| Category | Conferences - Seminars |
JOINT BIO- and ELECTRICAL ENGINEERING SEMINAR
Mid-infrared absorption spectroscopy in the molecular fingerprint region is widely used for chemical identification and quantitative analysis employing infrared absorption spectra databases. The ability to perform mid-infrared spectroscopy with nanometer spatial resolution is highly desired for applications in materials and life sciences. Currently, scattering near-field scanning optical microscopy (s-NSOM) is considered to be the most sensitive technique for nanoscale mid-infrared spectroscopy in ambient conditions. Here I will demonstrate that mid-infrared spectra can be obtained with comparable or higher sensitivity and spatial resolution by detecting mechanical forces exerted by molecules on the atomic force microscope tip upon light excitation. The mechanical approach to nanospectroscopy results in a simple optical setup which, unlike s-NSOM, is not affected by sample scattering, has no cryogenically-cooled mid-infrared detectors, and is easy to align. We demonstrate imaging and spectroscopy of molecular monolayer islands and estimate that only approximately 300 molecules contribute to cantilever deflection in our experiments.
I will also discuss our preliminary results aimed to extend this technique operation to aqueous environments and into the terahertz spectral range. Perspectives towards in-situ infrared spectroscopy with single-molecule sensitivity will be also discussed.
Mid-infrared absorption spectroscopy in the molecular fingerprint region is widely used for chemical identification and quantitative analysis employing infrared absorption spectra databases. The ability to perform mid-infrared spectroscopy with nanometer spatial resolution is highly desired for applications in materials and life sciences. Currently, scattering near-field scanning optical microscopy (s-NSOM) is considered to be the most sensitive technique for nanoscale mid-infrared spectroscopy in ambient conditions. Here I will demonstrate that mid-infrared spectra can be obtained with comparable or higher sensitivity and spatial resolution by detecting mechanical forces exerted by molecules on the atomic force microscope tip upon light excitation. The mechanical approach to nanospectroscopy results in a simple optical setup which, unlike s-NSOM, is not affected by sample scattering, has no cryogenically-cooled mid-infrared detectors, and is easy to align. We demonstrate imaging and spectroscopy of molecular monolayer islands and estimate that only approximately 300 molecules contribute to cantilever deflection in our experiments.
I will also discuss our preliminary results aimed to extend this technique operation to aqueous environments and into the terahertz spectral range. Perspectives towards in-situ infrared spectroscopy with single-molecule sensitivity will be also discussed.
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Practical information
- Informed public
- Free
Organizer
- Prof. Hatice Altug