Laser spectroscopies for elemental and molecular analysis in art and archaeology

Spectroscopic methods using laser sources have significantly improved our capacity to unravel the chemical composition of works of art and archaeological remains. Lasers enhance the performance of spectroscopic techniques which require intense light sources and specific analytical protocols assuring a microanalytical approach for analysis have been established. This review focuses on laser spectroscopic methods used in the field of cultural heritage diagnostics. Different materials and works of art have been investigated using laser spectroscopies and include Bronze Age ceramics, Minoan archeological remains, Ancient Roman buildings, Renaissance wall paintings and sculptures, manuscripts containing iron gall inks and colorants. Emphasis in this work is given to both the analytical capabilities of laser-based techniques for elemental and/or molecular analysis and in-situ use, spatial resolution and microanalysis, and a wide range of applications is described Spectroscopic methods are classified according to the elemental (LIBS, LA-ICP-MS) and molecular (LIF/LIDAR, Time resolved absorption spectroscopy, Laser desorption ionization mass spectrometries) information they yield. For non-destructive laser-induced fluorescence (LIF/LIDAR) and time-resolved fluorescence spectroscopy, imaging applications are described. The advantages provided by combined complementary techniques including but not limited to LIBS-LIF-Raman and LIBS-XRF are presented, as are recent advances in terms of chemical imaging. Finally, advances and applications of THz spectroscopy and non-linear spectroscopy and imaging are outlined.