Two systems capable of investigating linear scattering from nanoscopic systems are developed. The first is a Scanning Near-field Optical Microscope (SNOM), which is used to image near fields of optical antennas in the near-infrared (NIR) and visible regimes. The second is a scalable apparatus for detection and characterization of nanoparticles in solution, for which sensitivity to 30 nanometer particles with a bandwidth of > 1 kilohertz is demonstrated.
In SNOM, a sharp probe is scanned in the near field of an illuminated sample to create an image with resolution far exceeding the diffraction limit. Optical antennas are of interest as a SNOM sample because of their potential applications in energy harvesting, microscopy and light emission. The physics of optical antennas is not well understood, and near-field imaging is an important step in their design and development. The home-built SNOM presented in this thesis is one of the first to operate in the visible spectrum, where optical antennas are applicable. It uses phase-shifting interferometry to decouple amplitude and phase of scattered fields. The instrument is used to investigate near-field coupling of nanoparticles, and to image simple optical antennas fabricated with focused ion-beam lithography.
It has also been demonstrated that interferometric detection with elastic light scattering is a viable method for detection and characterization of nanoparticles in solution, which has applications in manufacturing, environmental monitoring, biodefense and medical research. Such methods have shortcomings, including small throughput and difficulty of scaling the apparatus to small sizes. The latter makes it impractical to use the device in the field or clinic. Therefore, a homebuilt dual-phase particle detection apparatus is presented, which makes two orthogonal interferometric measurements to decouple amplitude and phase of fields scattered from nanoparticles, and uses no active optical elements or lock-in detection. Benchmark sensitivity to 30nm particles with detection bandwidth > 1kHz is shown.
|Commitee:||Bigelow, Nick, Brown, Thomas, Donaldson, William, Hillenbrand, Rainer, Novotny, Lukas, Vamivakas, Nick|
|School:||University of Rochester|
|Department:||Hajim School of Engineering and Applied Sciences|
|School Location:||United States -- New York|
|Source:||DAI-B 73/07(E), Dissertation Abstracts International|
|Keywords:||Interferometry, Nano optics, Nanoparticle detection, Nsom, Phase-shifting, Snom|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be