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Dataset for Paper: High-energy terahertz surface optical rectification

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posted on 13.05.2020 by Luke Peters, Jacob Tunesi, Alessia Pasquazi, Marco Peccianti
Data for a research paper published in Nano Energy April 2018

The data provided is the data used to compile each of the 10 figures in the research paper. The .txt files contain the variables for the measured raw data contained in the related .mat file.

The format of the raw data is .mat - MATLAB binary -v7, which is compatible and portable to GNU Octave version >4.0 (tested). You will need access to the Matlab environment or GNU Octave environment to view these files.


Abstract

The 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.


Funding

The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007-2013/ under REA grant agreement no. [630833] and [327627]. We acknowledge the support of the U.K. Quantum Technology Hub for Sensors and Metrology, EPSRC, under Grant EP/M013294/1. J.T. acknowledges the support of the EPSRC through the studentship EP/N509784/1. This research received funding from the European Union’s Horizon 2020 research and innovation programme, grant agreement no 725046.

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