Terahertz absorption by cellulose: application to ancient paper artifacts

Peccianti, M., Fastampa, R., Mosca Conte, A., Pulci, O., Violante, C., Łojewska, J., Clerici, M. , Morandotti, R. and Missori, M. (2017) Terahertz absorption by cellulose: application to ancient paper artifacts. Physical Review Applied, 7, 064019. (doi: 10.1103/PhysRevApplied.7.064019)

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Abstract

Artifacts made of cellulose, such as ancient documents, pose a significant experimental challenge in the terahertz transmission spectra interpretation due to their small optical thickness. In this paper, we describe a method to recover the complex refractive index of cellulose fibers from the terahertz transmission data obtained on single freely standing paper sheets in the (0.2–3.5)-THz range. By using our technique, we eliminate Fabry-Perot effects and recover the absorption coefficient of the cellulose fibers. The obtained terahertz absorption spectra are explained in terms of absorption peaks of the cellulose crystalline phase superimposed to a background contribution due to a disordered hydrogen-bond network. The comparison between the experimental spectra with terahertz vibrational properties simulated by density-functional-theory calculations confirms this interpretation. In addition, evident changes in the terahertz absorption spectra are produced by natural and artificial aging on paper samples, whose final stage is characterized by a spectral profile with only two peaks at about 2.1 and 3.1 THz. These results can be used to provide a quantitative assessment of the state of preservation of cellulose artifacts.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Clerici, Professor Matteo
Authors: Peccianti, M., Fastampa, R., Mosca Conte, A., Pulci, O., Violante, C., Łojewska, J., Clerici, M., Morandotti, R., and Missori, M.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Physical Review Applied
Publisher:American Physical Society
ISSN:2331-7019
ISSN (Online):2331-7019
Copyright Holders:Copyright © 2017 American Physical Society
First Published:First published in Physical Review Applied 7:064019
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
Data DOI:10.5525/gla.researchdata.405

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
727471Quantum-enhanced THz spectroscopy and imagingMatteo ClericiEngineering and Physical Sciences Research Council (EPSRC)EP/P009697/1ENG - ENGINEERING ELECTRONICS & NANO ENG
771721EPSRC-ISF 2016: Quantum-enhanced THz detectorsMatteo ClericiEngineering and Physical Sciences Research Council (EPSRC)EP/P51133X/1ENG - ENGINEERING ELECTRONICS & NANO ENG