Jessica Afalla

Jessica Afalla
University of Tsukuba · Graduate School of Pure and Applied Sciences

PhD

Publications

Publications (65)
Article
Full-text available
We demonstrate that terahertz radiation can be generated from titanium-diffused magnesium oxide-doped lithium niobate optical strip waveguides when pumped by a single laser source with a wavelength of 1.55 μm. Titanium-in-diffusion was performed on a magnesium oxide-doped lithium niobate substrate by the deposition of titanium in a 40-µm wide strip...
Preprint
Full-text available
Epitaxial low temperature grown GaAs (LT-GaAs) on silicon (LT-GaAs/Si) has the potential for terahertz (THz) photoconductive antenna applications. However, crystalline, optical and electrical properties of heteroepitaxial grown LT-GaAs/Si can be very different from those grown on semi-insulating GaAs substrates (reference). In this study, we invest...
Article
Epitaxial low temperature grown GaAs (LT-GaAs) on silicon (LT-GaAs/Si) has the potential for terahertz (THz) photoconductive antenna applications. However, crystalline, optical and electrical properties of heteroepitaxial grown LT-GaAs/Si can be very different from those grown on semi-insulating GaAs substrates ("reference"). In this study, we inves...
Article
Full-text available
We present the implementation of an efficient terahertz (THz) photoconductive antenna (PCA) emitter design that utilizes high mobility carriers in the two-dimensional electron gas (2DEG) of a modulation-doped heterostructure (MDH). The PCA design is fabricated with recessed metal electrodes in direct contact with the 2DEG region of the MDH. We comp...
Conference Paper
We present threefold enhancement of terahertz emission from silicon nanowire (SiNW)-coated gallium-arsenide photoconductive antenna over its uncoated counterpart. The enhancement is attributed to the increased photoabsorption, and possibly additional photoconductive pathways induced by the SiNWs.
Article
Full-text available
***This is a peer-reviewed paper published in the JOURNAL OF THE JAPAN SOCIETY OF INFRARED SCIENCE AND TECHNOLOGY, Vol. 29, Issue No. 2, pp. 57-62 (February 2020).*** A spintronic bilayer structure, which consists of 2-nm Fe and 3-nm Pt epitaxial grown on 500-µm MgO substrate, was investigated as a terahertz (THz) source for different optical pump...
Conference Paper
Full-text available
Illuminating metallic spintronic heterostructures with ultrafast laser pulses can generate terahertz (THz) radiation due to spin current-to-charge current conversion. Such metallic spintronic heterostructures are essentially ultrathin ferromagnetic and non-ferromagnetic metallic layers stacked on appropriate substrates. They are particularly attrac...
Article
Carrier dynamics and photoconductivity in epitaxial-grown low-temperature GaAs on nominal and vicinal Si(1 0 0) substrates ('LT-GaAs/Si') were studied to predict their actual performance as THz photoconductive antenna (PCA) detectors. An optical-pump terahertz-probe technique was used to obtain the transmittance, carrier lifetime and photoconductiv...
Conference Paper
Full-text available
Spintronic heterostructures are emerging and interesting emitters of terahertz (THz) radiation. In the past, THz emission of spintronic layers is by an antenna-free approach. In this paper, we report on THz wave generation of a diabolo-shaped Fe/Pt spintronic antenna using a 780-nm wavelength pump beam from a femtosecond laser. THz emission amplitu...
Conference Paper
Full-text available
Terahertz (THz) generation of spintronic heterostructures is becoming popular due to broader THz bandwidth with tunable emission amplitude and polarization [1-2]. These heterostructures typically consist of stacks of ferromagnetic (FM) and nonmagnetic (NM) thin films which generate THz radiation either by the inverse spin-Hall [3] or the interface...

About

65
Publications
4,382
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94
Citations
Additional affiliations
March 2020 - present
University of Tsukuba
Position
  • Professor (Assistant)
September 2016 - February 2020
University of Fukui
Position
  • Researcher
March 2015 - August 2016
Kobe University
Position
  • PostDoc Position
Education
June 2010 - April 2014
University of the Philippines
Field of study
  • Physics

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