Wavelength Conversion through Plasmon-Coupled Surface States

Speaker: Deniz Turan
Affiliation: Ph.D. Candidate

Via Zoom: https://ucla.zoom.us/j/95524774892

Abstract: Surface states generally degrade semiconductor device performance by raising the charge injection barrier height, introducing localized trap states, inducing surface leakage current, and altering the electric potential. Therefore, there has been an endless effort to use various surface passivation treatments to suppress the undesirable impacts of the surface states. During my doctoral studies, I have investigated the unique electrochemical characteristics of semiconductor surface states and showed that the giant built-in electric field created by the surface states can be harnessed to enable passive wavelength conversion with unprecedented efficiencies without utilizing any nonlinear optical phenomena. Photo-excited surface plasmons are coupled to the surface states to generate an electron gas, which is routed to a nanoantenna array through the giant electric field created by the surface states. The induced current on the nanoantennas, which contains mixing product of different optical frequency components, generates radiation at the beat frequencies of the incident photons. We utilize the unprecedented functionalities of plasmon-coupled surface states to demonstrate passive wavelength conversion of nanojoule optical pulses at a 1550 nm center wavelength to terahertz regime with record-high efficiencies that exceed nonlinear optical methods by 4-orders of magnitude. The presented scheme can be used for optical wavelength conversion to different parts of the electromagnetic spectrum ranging from microwave to far-infrared regimes by using appropriate optical beat frequencies.

Biography: Deniz Turan is currently pursuing his Ph.D. under the supervision of Prof. Mona Jarrahi in Terahertz Electronics Laboratory. He has received his B.S. in Electrical and Electronics Engineering from Middle East Technical University in 2014 and his M.S. in Electrical Engineering at the University of California, Los Angeles in 2016. He is the recipient of the UCLA Dissertation Year Fellowship, IEEE Antenna and Propagation Society Doctoral Grant, and UCLA Henry Samueli Fellowship. His research results have appeared in 5 peer-reviewed journal papers and 19 conference proceedings. His research interests include designing terahertz sources and detectors with unique functionalities using plasmonic nanoantennas.

For more information, contact Prof. Mona Jarrahi (mjarrahi@ucla.edu)

Date/Time:
Date(s) - May 26, 2021
12:00 pm - 2:00 pm

Location:
Via Zoom Only
No location, Los Angeles
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