Peters_et_al-2018-Nano_Energy.pdf (543.39 kB)
High-energy terahertz surface optical rectification
journal contribution
posted on 2023-06-09, 11:55 authored by Luke Peters, Jacob Tunesi, Alessia Pasquazi, Marco PecciantiThe interest in surface terahertz emitters lies in their extremely thin active region, typically hundreds of atomic layers, and the agile surface scalability. The ultimate limit in the achievable emission is determined by the saturation of the several different mechanisms concurring to the THz frequency conversion. Although there is a very prolific debate about the contribution of each process, surface optical rectification has been highlighted as the dominant process at high excitation, but the effective limits in the conversion are largely unknown. The current state of the art suggests that in field-induced optical rectification a maximum limit of the emission may exist and it is ruled by the photocarrier induced neutralisation of the medium's surface field. This would represent the most important impediment to the application of surface optical rectification in high-energy THz emitters. We experimentally unveil novel physical insights in the THz conversion at high excitation energies mediated by the ultrafast surface optical rectification process. The main finding is that the expected total saturation of the Terahertz emission vs pump energy does not actually occur. At high energy, the surface field region contracts towards the surface. We argue that this mechanism weakens the main saturation process, re-establishing a clearly observable quadratic dependence between the emitted THz energy and the excitation. This is relevant in enabling access to intense generation at high fluences.
History
Publication status
- Published
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- Published version
Journal
Nano EnergyISSN
2211-2855Publisher
ElsevierExternal DOI
Volume
46Page range
128-132Department affiliated with
- Physics and Astronomy Publications
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Dataset for this article is available through the related URL.Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2018-02-06First Open Access (FOA) Date
2018-02-06First Compliant Deposit (FCD) Date
2018-02-06Usage metrics
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