Sheridan, Erin, C
(2022)
Nanoscale nonlinear optics with LaAlO3/SrTiO3 junctions.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Continued progress in nanometer-scale research and technologies relies on our ability to
characterize and control the optical and electronic behaviors of nanometer-scale objects over a
broad range of frequencies. This thesis focuses on the development of a one-of-a-kind molecularscale nonlinear optical platform that can electronically contact nanoscale analytes and probe their
optical responses over an extremely large range of frequencies. These devices consist of 10-
nanometer scale nanojunctions situated within the interface of the LaAlO3/SrTiO3 (LAO/STO)
heterostructure.
This dissertation begins with an introduction to LAO/STO in Chapter 1.0. This is followed
by a review of the experimental setup and methods used in this work in Chapter 2.0. Chapter 3.0
lays out an overview of the optical response of LAO/STO nanojunctions, and includes the first
original work of this thesis (Section 3.2), wherein I describe two-wave-mixing experiments
utilizing a ultrafast pulse shaping setup. A difference frequency generation response ranging from
1 to >100 THz is observed, demonstrating the ultra-broadband generation and detection
capabilities of LAO/STO nanojunctions.
Next, I describe results obtained when these devices are used to probe the nonlinear optical
response of graphene (Chapter 4.0) and graphene nanoribbons (Chapter 5.0). Time-domain
photovoltage measurements reveal >99.9% absorption of light in graphene in the visible-to-near
infrared range of the electromagnetic spectrum, where undoped graphene is typically transparent.
When these absorption features appear, the nonlinear optical response of the graphene is greatly
enhanced, suggesting the existence of high-energy plasmons. Similar results are observed in
graphene nanoribbons that are deposited on LAO using an AFM tip then integrated into a
nanojunction device, revealing the confined nature of the graphene response. Finally, in Chapter
6.0. I briefly describe experiments probing the interaction of two graphene/LAO/STO
nanojunctions. The work of this dissertation paves the way for new experiments, outlined in
Chapter 7.0.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
24 February 2022 |
| Date Type: |
Publication |
| Defense Date: |
16 November 2021 |
| Approval Date: |
24 February 2022 |
| Submission Date: |
23 September 2021 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
161 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Physics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
optics, nonlinear optics, ultrafast optics, plasmonics, graphene, LAO/STO, graphene nanoribbons |
| Date Deposited: |
24 Feb 2022 15:29 |
| Last Modified: |
24 Feb 2022 15:29 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/41832 |
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