Comprehensive spectral and imaging studies of marble to assess the environmental damage using ULF Raman and THz absorption studies

Puspita Chanda; Khushboo Singh; Uzair Aalam; Karl Bertling; Aparajita Bandyopadhyay; Aleksandar Rakic; Amartya Sengupta

doi:10.1117/12.2673785

9 August 2023 Comprehensive spectral and imaging studies of marble to assess the environmental damage using ULF Raman and THz absorption studies

Puspita Chanda, Khushboo Singh, Uzair Aalam, Karl Bertling, Aparajita Bandyopadhyay, Aleksandar Rakic, Amartya Sengupta

Author Affiliations +

Proceedings Volume 12620, Optics for Arts, Architecture, and Archaeology (O3A) IX; 126200F (2023) https://doi.org/10.1117/12.2673785
Event: SPIE Optical Metrology, 2023, Munich, Germany

Abstract

Taj Mahal, made of exquisite white calcite, continues to deteriorate due to the emission of sulphur dioxide, methane etc. by industries and vehicular exhaust caused by the dense population in the region. Our previous collaborative works on samples with Pietra-Dura works already showed damages and irregularities including surface discolouration due to methane, water inclusions in the volume, and sub-surface cracks employing micro-Raman spectroscopy, broadband Terahertz Time Domain Imaging (THz-TDI) and THz Laser Feedback Interferometry (THz-LFI). Here, two types of samples having similar artwork, but one made of marble having high sulphur content have been investigated. Employing energy dispersive X-Ray analysis (EDAX), the sulphur content in the previous calcite sample is found to be nil while the new one has 16% by weight. While visually the samples are similar, under optical and scanning electron microscopy (SEM), calcite presents grainier structure with larger porosity while the other one appears denser with finer porosity. In ultra-low-frequency (ULF) Raman spectroscopy, the calcite sample (less than 0.15% Mg content) produces a significant line at 1100 cm-1 while the marble with sulphur shows a markedly different spectral response with the significant line at 1010 cm-1 . Using both THz-TDI and THz Continues Wave (THz CW) imaging, we concluded that calcite marble has significantly larger THz penetration even at 1 THz, while the marble with high sulphur content has very low THz penetration even below 0.5 THz and high THz absorption offering higher THz reflectivity. These observations pave the way to objectively detect the extent of environmental damage to marble structures across the globe.

Citation Download Citation

Puspita Chanda, Khushboo Singh, Uzair Aalam, Karl Bertling, Aparajita Bandyopadhyay, Aleksandar Rakic, and Amartya Sengupta "Comprehensive spectral and imaging studies of marble to assess the environmental damage using ULF Raman and THz absorption studies", Proc. SPIE 12620, Optics for Arts, Architecture, and Archaeology (O3A) IX, 126200F (9 August 2023); https://doi.org/10.1117/12.2673785

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Terahertz radiation

Raman spectroscopy

Sulfur

Calcite

Scanning electron microscopy

Visualization

Spectroscopy

Show All Keywords

Keywords/Phrases

Search In:

Publication Years