Conventional lasers are limited in how small they can be made because the feedback component for photons in a laser, the optical resonator, must be at least half the size of the wavelength of the laser light. Photons cannot be confined to areas with dimensions much smaller than half their wavelength, or about 250 nanometers, thus limiting the extent to which optical devices can be integrated in complex circuitry. Miniaturization of lasers lies in the use of resonating noble metal particles which can support surface plasmon excitations. Surface plasmons can be confined in significantly smaller spaces than photons and can be converted into conventional light waves. When combined with gain-materials such as polyfluorene conjugated polymers or quantum dots, surface plasmons can be amplified, creating of a sub-wavelength scale device that produces intense, coherent emission of light. The term coined for this device is “SPASER” (surface plasmon amplification by stimulated emission of radiation). It is the SPASER that many photonics experts assert is the key component that will usher in the age of nanophotonics, and would facilitate dramatic increases in computing speeds (in the Terahertz regime) through the development of on-chip lasers and all-optical data processing. These innovations will simultaneously increase computing and energy efficiency. This project will address the design, synthesis and characterization of sub-wavelength light amplification devices consisting of silver nanoparticles and a variety of high-optical-gain materials.
- GPA: 3.5
- Course Experience: Physical Chemistry, Solid State Chemistry
Current Undergraduate Researchers
- Sarah Goodman
- Gary Cheung
- Divya Vijapurapu
- Alexa Abdelaziz
Publications with Undergraduate Co-authors
Surface Plasmon and Photonic Mode Propagation in Gold Nanotubes with Varying Wall Thickness. J. Kohl, M. Fireman, D. M. O'Carroll, Phys. Rev. B (2011) in press.
Surface Plasmon Assisted Absorption in Conjugated Polymer Thin Films and Devices. D. M. O’Carroll, A. X. Collopy, V. E. Ferry, H. A. Atwater, 25th EU PVSEC / WCPEC-5 Proc. 834-837 (2010)
Polyfluorene Nanowires with Pronounced Axial Texturing Prepared by Melt Assisted Template Processing. D. O’Carroll, J. Irwin, D. Tanner, G. Redmond, Mater. Sci. Eng. B 147, 298-302 (2008).