Remote laser spectroscopy at standoff distances for heritage applications

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Li, Y, 2022. Remote laser spectroscopy at standoff distances for heritage applications. PhD, Nottingham Trent University.

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Abstract

In this project, remote standoff laser spectroscopy systems working at 3–15 m have been developed for cultural heritage research, employing Raman spectroscopy, laser induced breakdown spectroscopy (LIBS), and laser induced fluorescence spectroscopy (LIF). To address the problems encountered during in situ analysis due to environmental restrictions, the adoption of remote techniques offers advantages such as convenient deployment on the ground, allowing sensitive measurements over long integration time and there is no need to redeploy for different areas of interest. The research focuses on the design and development of remote standoff laser spectroscopy systems with special needs in heritage research considered, as well as their application for in situ analysis.

A remote standoff Raman system was developed and optimised. It is the first of its kind that is dedicated to cultural heritage research. It can identify most of common historic artist pigments. A daylight subtraction procedure enables the remote standoff Raman system to operate in the presence of indoor ambient light. Laser induced degradation effect was studied using various laser configurations on a range of common pigments. The remote standoff Raman system is proved to be safe for the analysis of most pigments tested when using typical integration time required for Raman measurements. In situ remote macro-Raman mapping is achieved in two field campaigns, revealing the pigments distribution on wall paintings and salt distribution in historical buildings in costal environments.

A remote standoff LIBS system was developed. Assisted with Raman and reflectance spectroscopy, a multimodal approach allowing in situ standoff depth-resolved material identification of wall paintings was demonstrated for the first time. The combined elemental, molecular and reflectance information contributes to a more complete data interpretation. Consequently, the stratigraphy of whitewashed wall paintings was successfully uncovered in a unique field campaign.

Item Type:	Thesis
Creators:	Li, Y.
Date:	June 2022
Rights:	The copyright in this work is held by the author. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed to the author.
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	14 Feb 2023 13:51
Last Modified:	14 Feb 2023 13:51
URI:	https://irep.ntu.ac.uk/id/eprint/48289