Optical antennas have been widely used for variety of applications such as sensitive photodetection, efficient light emission, high-resolution imaging, heat-assisted magnetic recording, and surface-enhanced Raman spectroscopy (SERS) because they can capture and focus propagating electromagnetic energy into sub-diffraction-limited areas and vice versa. However, widespread application of optical antennas has been limited due to lack of appropriate methods for uniform and large area fabrication of antennas, as well as difficulty in achieving an efficient design with small mode volume (gap spacing < 10nm). <p> In this dissertation, we theoretically derived the local field enhancement of the optical antenna and found that optimized radiation and small gap spacing are required for maximum field enhancement of the antenna. To address these parameters, we experimentally demonstrated three different designs of optical antennas.
First, we report on applying a dipole antenna on a ground plane for radiation engineering. The dipole antenna design can achieve the optimum radiation condition by tuning the spacer thickness between the antenna array and the ground plane; however, reducing the gap spacing below 10 nm is challenging if using typical nanofabrication techniques such as e-beam lithography and focused ion beam milling.
Secondly, we report on using a patch antenna on ground plane for the uniform sub-5 nm gap spacing. The patch antenna design can be easily implemented with extremely small gaps; however, the poor radiation efficiency of the patch antenna with a nanometer-scale gap degrades the performance of the antenna.
Finally, we present a novel optical antenna design—the arch-dipole antenna—which has optimal radiation efficiency and small gap spacing (5 nm) fabricated by CMOS-compatible deep-UV spacer lithography. This antenna design achieves a strong SERS signal with an enhancement factor exceeding 108 compared to the arch-dipole antenna array; this is two orders of magnitude stronger than that obtained from the standard dipole antenna array fabricated by e-beam lithography. Because the antenna gap spacing—a critical dimension of the antenna—can be defined by deep-UV lithography, efficient optical antenna arrays with sub-10 nm gap can be mass-produced using current CMOS technology.
|Advisor:||Wu, Ming C.|
|Commitee:||Lee, Luke P., Yablonovitch, Eli|
|School:||University of California, Berkeley|
|Department:||Electrical Engineering & Computer Sciences|
|School Location:||United States -- California|
|Source:||DAI-B 75/08(E), Dissertation Abstracts International|
|Subjects:||Electrical engineering, Optics|
|Keywords:||Nanoantenna, Nanophotonics, Optical antenna, Optoelectronics, Plasmonics|
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