Ultrafast Optics and Terhertz Photonics

Lead Research Organisation: University of Sussex
Department Name: Sch of Mathematical & Physical Sciences

Abstract

The project will focus on efforts to access high THz field regimes. It will require access to Sussex's high-energy 100GW-class ultrafast laser infrastructure (readily available only to a limited number of other photonic research labs within the UK) and will involve the necessary training -an extremely valuable skill within the international scenario- for developing active research in the field of the physics of extreme optical excitations.

More specifically, the project targets the investigation of the nonlinear field-matter interaction induced by strong THz fields. In particular the PhD student will develop a low-noise 3uJ-level THz source based on the physics of the so called tilted-wave front nonlinear generation, the new frontier in the specific domain. Such a system will be deployed to gain a better understanding of ultrafast carrier dynamics of electron distributions in many materials diffused in electronics, and to explore novel regime a field induced carrier acceleration.

In addition, the research will investigate ways to enhance the THz field, theoretically and numerically designing devices for subwavelength confinement via the so-called surface-plasmons phenomenon. This project links a novel experimental activity with the ongoing of theoretical development within the research group.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509784/1 01/10/2016 30/09/2021
1805720 Studentship EP/N509784/1 01/10/2016 31/01/2021 Jacob Tunesi
 
Description I have investigated how intense optical fields interact with semiconductor surfaces to generate high energy terahertz (THz) pulses. I then exploited the specific physical mechanism behind the nonlinear conversion to study how the electrons diffuse at the surface. As upon ultrafast illumination, many hot electrons are generated which move to inhibit the emitted THz pulse and by mapping this screening of the THz pulse over time I can observe the dynamics highly specific to the surface.

I have then used this technique to study the surface electron dynamics to demonstrate the fundamental limits on the optical to THz conversion efficiency. Discovering that at extreme excitations it is possible to overcome the negative impact of the hot electrons at the surface.

The direct observation of electron motion at surfaces further enabled me to look at how charges transfer inside of new organic LED technologies. I have also used these techniques to investigate rough, structured surfaces where the excited electron motion isn't trivial and many complex interactions can occur. Lastly my work on THz generation and imaging systems has been used to develop a new camera operating at THz frequencies.
Exploitation Route My research group is currently further investigating the nonlinearities at surfaces as these structures represent essential breakthroughs in THz imaging where the image resolution is fundamentally determined by the thickness of the interaction region (thinner than the optical wavelength).
My work on the THz generation and charge motion in structured surfaces can be put forward to develop a new project line in the lab, where the structures are resonant at multiple wavelengths.
Sectors Chemicals,Digital/Communication/Information Technologies (including Software),Electronics,Energy,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology,Culture, Heritage, Museums and Collections,Pharmaceuticals and Medical Biotechnology,Security and Diplomacy

URL http://www.sussex.ac.uk/broadcast/read/44372
 
Description I am the inventor of a soon to be published patent.
First Year Of Impact 2017
Sector Security and Diplomacy
Impact Types Societal,Economic