Nanosecond time-resolved characterization of a pentacene-based room-temperature MASER

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Nanosecond time-resolved characterization of a pentacene-based room-temperature MASER

Salvadori, E; Breeze, JD; Tan, KJ; Sathian, J; Richards, B; Fung, MW; Wolfowicz, G; ... Kay, CW; + view all (2017) Nanosecond time-resolved characterization of a pentacene-based room-temperature MASER. Science Reports , 7 , Article 41836. 10.1038/srep41836. Green open access

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Abstract

The performance of a room temperature, zero-field MASER operating at 1.45 GHz has been examined. Nanosecond laser pulses, which are essentially instantaneous on the timescale of the spin dynamics, allow the visible-to-microwave conversion efficiency and temporal response of the MASER to be measured as a function of excitation energy. It is observed that the timing and amplitude of the MASER output pulse are correlated with the laser excitation energy: at higher laser energy, the microwave pulses have larger amplitude and appear after shorter delay than those recorded at lower laser energy. Seeding experiments demonstrate that the output variation may be stabilized by an external source and establish the minimum seeding power required. The dynamics of the MASER emission may be modeled by a pair of first order, non-linear differential equations, derived from the Lotka-Volterra model (Predator-Prey), where by the microwave mode of the resonator is the predator and the spin polarization in the triplet state of pentacene is the prey. Simulations allowed the Einstein coefficient of stimulated emission, the spin-lattice relaxation and the number of triplets contributing to the MASER emission to be estimated. These are essential parameters for the rational improvement of a MASER based on a spin-polarized triplet molecule.

Type:	Article
Title:	Nanosecond time-resolved characterization of a pentacene-based room-temperature MASER
Location:	England
Open access status:	An open access version is available from UCL Discovery
DOI:	10.1038/srep41836
Publisher version:	http://doi.org/10.1038/srep41836
Language:	English
Additional information:	Copyright © The Author(s) 2017. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
UCL classification:	UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology
URI:	https://discovery.ucl.ac.uk/id/eprint/1540339