Frontier, innovative research performed by the “PHOTONICS FOR HERITAGE SCIENCE (HS)” group for over twenty years has positioned IESL-FORTH among the leading centers worldwide for scientific research and technological development of cutting-edge laser and optical tools that offer new and efficient approaches to the diagnostics and conservation of works of art and antiquities. Emphasis is placed on: a) laser ablation methodologies for cleaning and restoration, b) laser spectroscopy for compositional analysis, c) multi spectral imaging and d) holographic metrology techniques for structural diagnosis.

The vision and the mission of this activity has been to develop state-of-the-art laser-based methods in order to a) enhance our understanding about cultural heritage (CH) materials and processes and b) provide versatile and effective tools for the analysis, diagnosis, preservation and restoration of archaeological/historical objects, works of art, and monuments.

The principal axes and the main developmental objectives of the individual activities are highlighted in the following:

 

Research Topics

Research at the Laser Cleaning (LC) group is developing novel laser ablation methodologies in order to meet a number of diverse conservation and cleaning challenges.

Highlights of this activity are:

  1. The initiation of a Bilateral collaboration between IESL-FORTH and the Conservation department of the PALACE MUSEUM in Beijing, CHINA with the aim to organize a common Laser Technology Joint Laboratory on Cultural Heritage with the name “NIKI” currently under the "One belt, One road initiative".
  2. The development of a prototype laser system and methodology for the removal of pollution encrustation from the Parthenon Sculptures, which ensures safe and controlled cleaning without discoloration side-effects. This methodology is being applied since 2002 in a number of sculptures at the Athenian Acropolis Monuments (i.e. the West Frieze, metopes and pedimental sculptures of the Parthenon, the >Frieze of the Athena Nike Temple, and the roof of the Caryatids’ porch in the Erechtheion).
    Since 2011 it has been also included in the regular conservation practice of the Acropolis Museum and along these lines an advanced laser laboratory has been set up on the visitors’ floor where the Caryatids are exhibited. Removal of pollution accumulations from their surface takes place in this laboratory while visitors can follow live the cleaning process is carried out. Further synergies between the Acropolis Museum and IESL-FORTH have been planned in the context of an “open common laboratory” in which modern laser-based diagnostic and imaging techniques will be used for expanding the knowledge and deciding the best conservation practices for the exhibits.

Current research and activities aimed at:

Additionally, the implementation of laser technology to other challenges in Heritage Conservation is investigated.

Recently research efforts have been focused on the restoration of cracks and other pathologies found on the surface of glazed ceramics using laser irradiation; cracked glazed surfaces have been restored on the principle of laser-induced local and controlled melting of the existing glaze material (Restoration of vitreous surfaces using laser technology).

The main direction of the optical imaging activity is to develop new methods for the non-contact, non-invasive, in-situ examination and continuous inspection of CH objects. Applications include:

on the basis of reflectance imaging and spectroscopy. The goal of this research is to investigate, quantify and expand the potential applications of spectral imaging on CH objects, while continuous technical developments both in hardware and software target to improve analytical capabilities.

Recently, a novel technique, Photoacoustic Imaging, predominantly developed in the context of biomedical research, has been applied on CH objects. The photoacoustic signal can overcome limitations of light and offer substantially improved detection sensitivity at high spatial resolution. The technique has been proved to be capable of uncovering “hidden” features in multi-layered CH objects such as paintings and determining the thickness of thin layers thus providing micrometric precision stratigraphic information. Finally, the potential of applying the photoacoustic signal for the in situ and real-time monitoring of laser cleaning interventions is currently investigated.

Laser Spectroscopic Analysis is necessary and sometimes vital for the examination of CH objects, since it provides information not only for their constituents but also for deterioration materials, pollutants and other substances that have developed throughout time on the objects and may lead to their aesthetic and structural decline. 

Timely and accurate detection of these deterioration materials can lead to proper conservation and restoration treatments, which can safeguard and actually save the CH objects. Moreover, a series of questions can be answered such as the authenticity of artworks, style of the painter, etc, aiding the art historians to extract important information about the artist and his/her era. Furthermore, spectroscopic techniques can be applied to monitor various processes related to the protection of CH objects, such as the controlled removal of unwanted layers/encrustations, etc. using either laser radiation or any other conventional tools and methods.

PhoHS laboratory of IESL-FORTH has many years of expertise in a series of laser spectroscopic techniques, such as LIBS, LIF, Raman, SERS as well as spectroscopic techniques that use other light sources like LED-IF and Diffuse Reflectance. Along with the laboratory setups, compact/portable laser-based analytical instruments have been developed for in situ and field-deployable applications combining different spectroscopies in hybrid arrangements.

 

Laser Interferometry for Structural Diagnostics. The main direction of this activity is to investigate deformation, deterioration and fracture mechanisms in order to evaluate the structural condition of materials and systems.

The remote optical sensing of almost invisible defects and alterations, which allows their location, measurement and exact positioning within the structure of the object,  as well as their monitoring through

  • environmental and climate changes,
  • conservation treatments,
  • natural or provoked ageing,
  • transportation or handling

are among the objectives of this research group.

This is achieved by the effective transfer of interferometric techniques and know-how to CH applications (artworks and monuments) and the continuous inspiration, design, development and implementation of new experimental processes, methodologies and instruments in order to exploit the full potential of laser metrology.

Since 2012 PhoHS at IESL-FORTH organises a series of training activities inviting conservators, conservation scientists, and other Heritage disciplines for an exciting journey to Crete to become acquainted with the latest developments on non-invasive optical technologies and explore their field applications in Cultural Heritage research and conservation.

The aim of OPTO-CH summer courses is to introduce participants to the applications of advanced laser-based technologies in Heritage Science. Lectures from experts on modern laser diagnostic and analytical techniques and laser cleaning methodologies are combined with practical demonstrations and laboratory hands-on sessions. Field experiments on-site at a selected monument in Crete are organised in order to demonstrate the applicability of the techniques in practice.

Further info at https://opto-ch.iesl.forth.gr/

 

 

ECHOES - European Cloud for Heritage OpEn Science,
PERCEIVE- Perceptive Enhanced Realities of Colored collEctions through AI and Virtual Experiences
E-RIHS IP - European Research Infrastructure for Heritage Science Implementation Phase
China-Greece Belt and Road Joint Laboratory on CH Conservation Technology
4CH - Competence Centre on the Conservation of Cultural Heritage
SpArch - Spectrochemical Analysis of Archaeological Bio-Organic Residues
ΠΡΩΤΕΑΣ - Advanced System for collection and management of analytical data for documentation and conservation of large-scale paintings in an open laboratory
CALLOS - Conservation of Athens antiquities with Laser and Lidar technologies Open to Science and public
IPERION-HS, Integrating Platforms for the European Research Infrastructure ON Heritage Science
SSHOC -Social Sciences & Humanities Open Cloud
Heritage Resilience Against CLimatic Events on Site
POLITEIA-II "Advanced analytical, diagnostic, surveying and documentation technologies in Cultural Heritage - II"
PARTHENOS - “Pooling Activities, Resources and Tools for Heritage E-research Networking, Optimization and Synergies”
Integrated Platform for the European Research Infrastructure ON Culture Heritage
Photonics for Heritage Science - PAST PROJECTS
Open-air Laser-induced Breakdown Spectroscopy (LIBS)
I. Malegiannaki, D. Anglos
Analytical Strategies for Cultural Heritage Materials and their Degradation, Volume:1, Page:45-74, Year:2021, DOI:doi.org/10.1039/9781788015974-00045
Review and New Evidence on the Molluscan Purple Pigment Used in the Early Late Bronze Age Aegean Wall Paintings
S. Sotiropoulou, I. Karapanagiotis, K. S. Andrikopoulos, T. Marketou, K. Birtacha, M. Marthar
Heritage, Volume:4, Issue:1, Page:171-187, Year:2021, DOI:doi.org/10.3390/heritage4010010
Application of laser-induced breakdown spectroscopy and neural networks on archaeological human bones for the discrimination of distinct individuals
P. Siozos, N. Hausmann, D. Anglos
Journal of Archaeological Science: Reports, Volume:32, Page:102769, Year:2021, DOI:doi.org/10.1016/j.jasrep.2020.102769
Wall Mosaics: A Review of On-Site Non-Invasive Methods, Application Challenges and New Frontiers for Their Study and Preservation
A.Chaban, R. Deiana, V. Tornari
Journal of Imaging, Volume:6, Issue:10, Page:108, Year:2021, DOI:doi.org/10.3390/jimaging6100108
Listening to laser light interactions with objects of art: a novel photoacoustic approach for diagnosis and monitoring of laser cleaning interventions
Tserevelakis, G.J., Pouli, P., Zacharakis, G.
Heritage Science, Volume:8, Issue:1, Page:98, Year:2020, DOI:doi.org/10.1186/s40494-020-00440-w
Materials analyses of stone artifacts from the EBA to MBA Minoan Tholos tomb P at Porti, Greece (Crete), by means of Raman spectroscopy: Results and a critical assessment of the method
G. Flouda, A. Philippidis, A. Mikallou, D. Anglos
Journal of Archaeological Science: Reports, Volume:32, Page:102436, Year:2020, DOI:doi.org/10.1016/j.jasrep.2020.102436
Development of a hybrid photoacoustic and optical monitoring system for the study of laser ablation processes upon the removal of encrustation from stonework
A. Papanikolaou, G. J. Tserevelakis, K. Melessanaki, C. Fotakis, G. Zacharakis and P. Pouli
Opto-Electronic Advances, Volume:3, Issue:2, Page:190037-1, Year:2020, DOI:doi.org/10.29026/oea.2020.190037
Heat transfer effects on defect boundaries captured by digital holographic interferometry and infrared thermography workstation: An overview on experimental results
V. Tornari, M. Andrianakis, A. Chaban, K. Kosma
Experimental Techniques, Volume:44, Issue:1, Page:59-74, Year:2020, DOI:doi.org/10.1007/s40799-019-00336-w
Non-invasive photoacoustic detection of hidden underdrawings in paintings using air-coupled transducers
G. J. Tserevelakis, P. Siozos, A. Papanikolaou, K. Melessanaki, G. Zacharakis
Ultrasonics, Volume:98, Page:94-98, Year:2019, DOI:doi.org/10.1016/j.ultras.2019.06.008
Combined multiphoton fluorescence microscopy and photoacoustic imaging for stratigraphic analysis of paintings
G.J. Tserevelakis, V. Tsafas, K. Melessanaki, G. Zacharakis, G. Filippidis
Optics Letters, Volume:44, Page:1154-1157, Year:2019, DOI:doi.org/10.1364/OL.44.001154
Cleaning of gypsum-rich black crusts on granite using a dual wavelength Q-Switched Nd:YAG laser
J.S. Pozo-Antonio, A Papanikolaou, A. Philippidis, K. Melessanaki, T. Rivas, P. Pouli
Construction and Building Materials , Volume:226, Page:721-733, Year:2019, DOI:doi.org/10.1016/j.conbuildmat.2019.07.298
Extensive elemental mapping unlocks Mg/Ca ratios as climate proxy in seasonal records of Mediterranean limpets
N. Hausmann, A. L. Prendergast, A. Lemonis, J. Zech, P. Roberts, P. Siozos, D. Anglos
Scientific Reports, Volume:9, Page:3698, Year:2019, DOI:doi.org/10.1038/s41598-019-39959-9
Laser cleaning of paintings: in situ optimization of operative parameters through non-invasive assessment by optical coherence tomography (OCT), reflection FT-IR spectroscopy and laser induced fluorescence spectroscopy (LIF)
P. Moretti, M. Iwanicka, K. Melessanaki, E. Dimitroulaki, O. Kokkinaki, M. Daugherty, M. Sylwestrzak, P. Pouli, P. Targowski, K.J. van den Berg, L. Cartechini and C. Miliani
Heritage Science, Volume:7, Page:44, Year:2019, DOI:doi.org/10.1186/s40494-019-0284-8
Combined photoacoustic imaging to delineate the internal structure of paintings
A Dal Fovo, G. Tserevelakis, A. Papanikolaou, G. Zacharakis, R. Fontana
Optics Letters, Volume:44, Issue:4, Page:919-922, Year:2019, DOI:doi.org/10.1364/OL.44.000919
Introducing the HERACLES Ontology – Semantics for Cultural Heritage Management
Tobias Hellmund, Philipp Hertweck, Désirée Hilbring,Jürgen Mossgraber, George Alexandrakis, Paraskevi Pouli, Amalia Siatou and Giuseppina Padeletti
Heritage, Volume:1, Page:377-391, Year:2018, DOI:dx.doi.org/10.3390/heritage1020026
Laser-Assisted Removal of Graffiti from Granite: Advantages of the Simultaneous Use of Two Wavelengths
J. S. Pozo-Antonio, A. Papanikolaou, K. Melessanaki, T. Rivas, P. Pouli
Coatings, Volume:8, Issue:4, Page:124, Year:2017, DOI:doi.org/10.3390/coatings8040124
‘‘POLYGNOSIS’’: the development of a thesaurus in an Educational Web Platform on optical and laser-based investigation methods for cultural heritage analysis and diagnosis
N. Platia, M. Chatzidakis, C. Doerr, L. Charami, Ch. Bekiari, K. Melessanaki, K. Hatzigiannakis, P. Pouli
Heritage Science, Volume:5, Issue:50, Page:1, Year:2017, DOI:doi.org/10.1186/s40494-017-0163-0
Portable laser-induced breakdown spectroscopy/diffuse reflectance hybrid spectrometer for analysis of inorganic pigments
P. Siozos, A. Philippidis, D. Anglos
Spectrochimica Acta Part B , Volume:137, Issue:1, Page:93-100, Year:2017, DOI:doi.org/10.1016/j.sab.2017.09.005
A method for the registration of spectral images of paintings and its evaluation
A. Zacharopoulos, K. Hatzigiannakis, P. Karamaoynas, V. M. Papadakis, M. Andrianakis, K. Melessanaki, X. Zabulis
Journal of Cultural Heritage , Volume:29, Page:10-18, Year:2017, DOI:doi.org/10.1016/j.culher.2017.07.004
Nonlinear imaging microscopy for assessing structural and photochemical modifications upon laser removal of dammar varnish on photosensitive substrates
M. Oujja, S. Psilodimitrakopoulos, E. Carrasco, M. Sanz, A. Philippidis, A. Selimis, P. Pouli, G. Filippidis, M. Castillejo
Physical Chemistry Chemical Physics, Volume:19, Page:22836-22843 , Year:2017, DOI:doi.org/10.1039/C7CP02509B
Elemental mapping of Mg/Ca intensity ratios in marine mollusc shells using laser-induced breakdown spectroscopy
N. Hausmann, P. Siozos, A. Lemonis, A. C. Colonese, H. K. Robson, D. Anglos
J. Anal. At. Spectrom., Volume:32, Page:1467-1472 , Year:2017, DOI:doi.org/10.1039/C7JA00131B
Materials analyses of pyrotechnological objects from LBA Tiryns, Greece, by means of Laser-Induced Breakdown Spectroscopy (LIBS): Results and a critical assessment of the method
A. Brysbaert, P. Siozos, M. Vetters, A. Philippidis, D. Anglos
Journal of Archaeological Science , Volume:83, Page:49-61, Year:2017, DOI:dx.doi.org/10.1016/j.jas.2017.06.007
A multi-technique approach, based on mobile/portable laser instruments, for the in-situ pigment characterization of stone sculptures on the island of Crete dating from Venetian and Ottoman period
Z. E. Papliaka, A. Philippidis, P. Siozos, M. Vakondiou, K. Melessanaki, D. Anglos
Heritage Science, Volume:4, Issue:15, Year:2016, DOI:doi.org/10.1186/s40494-016-0085-2
SERS and 2D-Fluorescence for the investigation of aminoacids and egg proteins
A. Philippidis, Z. E. Papliaka, D. Anglos
Microchemical Journal, Volume:126, Page:230-236, Year:2016, DOI:doi.org/10.1016/j.microc.2015.12.008
Laser-assisted removal of dark cement crusts from mineral gypsum (selenite) architectural elements of peripheral monuments at Knossos
G. Grammatikakis, K.D. Demadis, K. Melessanaki, P. Pouli
Studies in Conservation, Volume:60, Page:S3-S11 , Year:2015, DOI:doi.org/10.1179/0039363015Z.000000000201

Heads

Dr. Pouli Paraskevi
Senior application Scientist
Prof. Anglos Demetrios
University Faculty Member

Scientific Staff

Prof. Fotakis Costas
Professor Emeritus
Prof. Sotiropoulou Sophia
University Faculty Member

Technical Staff

Mr. Hatzigiannakis Kostas
Technical Scientist
Mr. Andrianakis Michalis
Technical Scientist
Ms. Melessanaki Kristalia
Technical Scientist
Mr. Englezis Apostolos
Technical Scientist

Research Associates

Dr. Tornari Vivi
PostDoctoral Fellow
Dr. Siozos Panagiotis
PostDoctoral Fellow
Dr. Philippidis Aggelos
PostDoctoral Fellow
Dr. Kokkinaki Olga
PostDoctoral Fellow
Dr. Pinon Hermida Victor
PostDoctoral Fellow
Dr. Tserevelakis George
PostDoctoral Fellow
Dr. Roumpou Maria
PostDoctoral Fellow

Students

Ms. Konstantinou Maria Eleni
Ph.D. student

Alumni

Prof. Austin Nevin
Alumni
Dr. Hausmann Niklas
PostDoctoral Fellow
Dr. Kogou Sotiria
PostDoctoral Fellow
Ms. Papanikolaou Athanasia
PostDoctoral Fellow
Dr. Papliaka Zoi Eirini
PostDoctoral Fellow
Dr. Kosma Kyriaki
Alumni
Dr. Papadakis Vassilis
Alumni
Ms. Bernikola Irini
Alumni
Ms. Kelegkouri Lamprini
M.Sc. student
Dr. Giakoumaki Anastasia
PostDoctoral Fellow
Mr. Chatzigiannis Dimitrios
Ph.D. student
Mr. Spanos Lampros
Ph.D. student
Ms. Malegiannaki Irene
M.Sc. student
Ms. Dimitroulaki Evdoxia
M.Sc. student
Mr. Intzes Dimitrios
Undergraduate trainee
Ms. Klironomou Evgenia
Undergraduate trainee
Ms. Avgerou Nefeli
Undergraduate trainee

PhoHS Infrastructure and Portable Instrumentation 

Access provider: Photonics for Heritage Science, IESL, FORTH

The researchers of IESL-FORTH, respond to the need for on-site material analysis with the development of portable or transportable instrumentation that has been optimized for in situ applications. A long list of related activities includes integrated analytical approaches applied in several field campaigns at museums and archaeological sites in Greece, Europe and the Middle East. The developed portable instrumentation includes:

  • Laser Induced Breakdown Spectroscopy system
  • Diffuse reflectance Spectroscopy
  • micro-Raman Spectroscopy system,

Services

  • Analysis and chemical characterization of materials in archaeological objects, artworks or historic monuments such as metals, stones, glass, paints and pigments, organic materials, etc.
  • In-depth analysis of multilayered surfaces
  • Investigation of degradation materials on different substrates

 

Related info

http://www.iesl.forth.gr/research/laser.aspx

 

Infrastructure Equipment

IESL-FORTH holds a number of laser systems with different wavelength, pulse duration and energy output characteristics available for laser cleaning investigations such as:

  • Transportable Q-switched Nd:YAG lasers (Quantel Q-smart 850, LITRON TRLi, Spectron SL-805 modified, Quanta Palladio, BMI 5022 DNS 10) emitting both nano- and pico-second (EKSPLA SL 312) laser pulses at various wavelengths (such as 1064, 532, 355, 266 & 213 nm)
  • Various excimer lasers emitting nano, pico and femto-second pulses in the UV
  • A patented transportable ns Nd:YAG system with dual-wavelength beam output, developed for the laser cleaning project of the Athens Acropolis Monuments especially dedicated to remove pollution crust from stonework without any discoloration or damage
  • A transportable LQS Nd:YAG system (ElEn, EOS1000) emitting IR pulses at longer pulse-widths
  • An Er:YAG laser system (LITRON NANO L 200-20-Er) emitting at 2094 nm 
  • A continuous CO2 laser system (Coherent Diamond C20) for the patented application related to the laser conservation of glazed objects.

Various workstations adaptable for different laser cleaning applications with the ability to integrate different optical and opto-mechanical components for the most appropriate beam delivery and control are available such as:

  • Handheld units (using a articulated mirrored arm) 
  • Automated beam scanning units for micrometer control and guidance of the laser beam to the sample (i.e. the painting surface).

The latter, a computer-driven mechanized component, can be adjusted on the basis of fluence values, spot size and pulse repetition rate enabling thus the homogeneous scanning of predefined areas.

Furthermore, a number of multi-modal diagnostic instruments for in-situ assessment of the cleaning result and monitoring of the laser ablation procedure are also availableThese can be selected according to the specifications of each individual cleaning case and may be one or more of the following:

  • Spectral Imaging to visualise the cleaning state
  • Laser-Induced Fluorescence (LIF) to evaluate the thinning of varnish
  • Vis-NIR Diffuse Reflectance spectroscopy to chemically characterise the irradiated surfaces

PhoHS group has developed an innovative, transportable ns Nd:YAG system with dual-wavelength (2λ) beam output.

The 2λ prototype, is capable of operating at two wavelengths simultaneously (infrared at 1064nm and ultraviolet at 355nm) and is able to remove thick pollution accumulations in a controlled and safe way for both the object and the operator. The combination of the two wavelengths ensures that no discoloration or damaging phenomena occur on the original substrate while revealing its unique ancient surface. The system is being used on the Athenian Acropolis Sculptures since 2000 till nowadays.

 The two-wavelength laser cleaning methodology was suggested and developed in 2001 aiming to address a number of conservation challenges and side-effects; yellowing discoloration of stone surfaces being the most characteristic. The methodology allows the regulation of different laser material ablation regimes and thus can be adapted to different cleaning issues with emphasis to cases in which conventional laser cleaning methodologies (i.e. using IR wavelengths) are not effective or successful. As a general rule for the combination of the 1064nm and 355nm their relative ratio is determined on the basis of the composition and morphology of the material to be removed. In order to remove relatively thick and inhomogeneous crusts the contribution of the IR beam (which is highly absorbed by the bulk of the crust) must be dominant, while for thinner soiling layers UV favoured ablation is recommended. Further research and fine-tuning, of the 2λ methodology on different cleaning challenges provided encouraging results as for example the combination of 1064nm and 532 nm, which has been found particularly promising for the removal of biological encrustation from stonework.

Ιn 2012 the International Institute for Conservation of Historic and Artistic Works (IIC) appreciated the collaborative efforts of the Acropolis Museum and IESL-FORTH to remove controllably dark pollution crusts and reveal the authentic marble sculptures on the basis of this prototype laser system which was operating openly (but safely) at the Museum. The 2012 Keck award was jointly given to the two organisations highlighting the Laser rejuvenation of Caryatids opens to the public at the Acropolis Museum: A link between ancient and modern Greece”.