Optical antenna arrays on a fiber facet for in situ surface-enhanced Raman scattering detection
| Autor: | Michael D. Dickey, George M. Whitesides, Jiming Bao, Elizabeth J. Smythe, Federico Capasso |
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| Rok vydání: | 2009 |
| Předmět: |
Optical fiber
Materials science business.industry Mechanical Engineering Nanoprobe Physics::Optics Bioengineering Polarization-maintaining optical fiber General Chemistry Condensed Matter Physics Article law.invention symbols.namesake Optics law Fiber optic sensor symbols General Materials Science Fiber business Raman spectroscopy Electron-beam lithography Raman scattering |
| Zdroj: | Nano letters. 9(3) |
| ISSN: | 1530-6984 |
| Popis: | This paper reports a bidirectional fiber optic probe for the detection of surface-enhanced Raman scattering (SERS). One facet of the probe features an array of gold optical antennas designed to enhance Raman signals, while the other facet of the fiber is used for the input and collection of light. Simultaneous detection of benzenethiol and 2-[(E)-2-pyridin-4-ylethenyl]pyridine is demonstrated through a 35 cm long fiber. The array of nanoscale optical antennas was first defined by electron-beam lithography on a silicon wafer. The array was subsequently stripped from the wafer and then transferred to the facet of a fiber. Lithographic definition of the antennas provides a method for producing two-dimensional arrays with well-defined geometry, which allows (i) the optical response of the probe to be tuned and (ii) the density of "hot spots" generating the enhanced Raman signal to be controlled. It is difficult to determine the Raman signal enhancement factor (EF) of most fiber optic Raman sensors featuring hot spots because the geometry of the Raman enhancing nanostructures is poorly defined. The ability to control the size and spacing of the antennas enables the EF of the transferred array to be estimated. EF values estimated after focusing a laser directly onto the transferred array ranged from 2.6 x 10(5) to 5.1 x 10(5). |
| Databáze: | OpenAIRE |
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