Combined TPEF and SHG Imaging for the Microstructural
Characterization of Different Wood Species Used in Artworks

Year: 2022

Authors: Dal Fovo A., Mattana S., Marchetti M., Anichini M., Giovannelli A., Baria E., Fontana R., Cicchi R.

Autors Affiliation: National Research Council, National Institute of Optics (CNR-INO), Largo E. Fermi 6, 50125 Firenze, Italy;

Department of Physics, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, Italy;

European Laboratory for Non-Linear Spectroscopy (LENS), Via N. Carrara 1, 50019 Sesto Fiorentino, Italy

National Research Council, Institute of BioEconomy (CNR-IBE), Via Madonna del Piano 10,
50019 Sesto Fiorentino, Italy;

National Research Council, Research Institute on Terrestrial Ecosystems (CNR-IRET), Via Madonna del
Piano 10, 50019 Sesto Fiorentino, Italy

Abstract: The morphological and chemical conformation of wood microstructures is characteristic
of individual species and strongly influences the macromechanical properties of the material, as
well as its sensitivity to deterioration factors. Noninvasive techniques enabling the visualization of
wood microstructures, while simultaneously providing compositional information, can significantly
facilitate the analysis of wooden artworks for conservation purposes. In this paper, we present the
application of combined two-photon excited fluorescence (TPEF) and second-harmonic generation
(SHG) imaging as a versatile diagnostic tool for the microcharacterization of three hardwood species
never analyzed by this method. Multimodal mapping of the molecular constituents based on the
detected nonlinear signals provides useful information for studying the biological and biochemical
deterioration of wood, opening a new field of application for a well-established and widely used
imaging technology.

Journal/Review: PHOTONICS

Volume: 9      Pages from: 170  to: 181

KeyWords: second-harmonic generation; two-photon excited fluorescence; wood microstructure;
cellulose; lignin; starch