Laser-induced emission, fluorescence and Raman hybrid setup: A versatile instrument to analyze materials from cultural heritage

Syvilay, Delphine; Bai, Xueshi; Wilkie-Chancellier, Nicolas; Texier, Annick; Martinez, L.; Serfaty, Sylvia; Detalle, Vincent

doi:10.1016/j.sab.2017.12.006

Cited by 13 publications

(5 citation statements)

References 13 publications

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“…Given the more stringent requirements for measurements to be non-invasive in heritage material analysis, it was thought that remote standoff Raman spectroscopy for heritage science should use CW lasers unlike other remote Raman spectroscopy applications (e.g., explosives detection) where pulsed laser was typically used [ 19 – 21 ]. It is worth noting that pulse lasers are employed in hybrid laser-based systems involving Raman spectroscopies for cultural heritage applications recently [ 22 – 24 ]. However, there is limited data on the damage threshold comparisons for CW and pulsed lasers on relevant materials.…”

Section: Laser-induced Degradation Testsmentioning

confidence: 99%

A study of potential laser-induced degradation in remote standoff Raman spectroscopy for wall paintings

et al. 2022

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A mobile remote standoff Raman spectroscopy system operational at typical distances of 10 m was developed specifically for research of historical sites and wall paintings recently. Here we present an upgrade to that system informed by a thorough experimental investigation of the relevant laser-induced degradation issues. Reflectance spectroscopy as a more sensitive technique than Raman spectroscopy was used for monitoring and a new phenomenon of reversible alterations was detected in many paint samples at very low laser intensities of less than 1 W/cm2 when Raman measurements detected no changes. Contrary to conventional wisdom, the intensity threshold for safe operation was found to decrease significantly for larger incident irradiation area in the case of a vermilion oil paint sample. Damage threshold in intensity for each material needs to be determined for different spot sizes, which can be orders of magnitude lower for 1 mm spot size compared with micro-Raman. Results from this study is also relevant to portable Raman systems which use similarly large spot sizes. However, the larger spot size still generates more Raman photons overall under safe operation than micro-Raman systems. Continuous-wave (CW) lasers are found to be best suited to efficient, that is more Raman signal detected over a given measurement time, and safe Raman operation than ns-pulse lasers at the same wavelength. While the damage threshold in intensity for ns-pulse lasers is much higher than that of CW lasers, the pulse energy allowed in one pulse for safe operation is still too low to allow detection of Raman signal, and the need for multiple pulses makes pulse laser inefficient owing to the low repetition rate necessary to ensure adequate heat dissipation between pulses. The safety of the upgraded system was evaluated and found that no permanent laser-induced degradation was detected within 60 s of laser irradiation for any of the paint samples.

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Section: Laser-induced Degradation Testsmentioning

confidence: 99%

A study of potential laser-induced degradation in remote standoff Raman spectroscopy for wall paintings

et al. 2022

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“…Since living cell is a highly dynamical system, separate sequential measurements of fluorescence and Raman tend to misdirect the location where Raman spectrum is observed. In order to avoid this misplacement, there have been various attempts to observe Raman and fluorescent spectra simultaneously [4][5][6][7][8][9][10][11][12]. In the present study, we demonstrate a new approach "simultaneous Raman/GFP microspectroscopy."…”

Section: Introductionmentioning

confidence: 95%

Organelle specific simultaneous Raman/green fluorescence protein microspectroscopy for living cell physicochemical studies

Wattanavichean

Nishida

Ando

et al. 2020

Journal of Biophotonics

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We demonstrate a novel bio-spectroscopic technique, "simultaneous Raman/GFP microspectroscopy". It enables organelle specific Raman microspectroscopy of living cells. Fission yeast, Schizosaccharomyces pombe, whose mitochondria are green fluorescence protein (GFP) labeled, is used as a test model system. Raman excitation laser and GFP excitation light irradiate the sample yeast cells simultaneously. GFP signal is monitored in the anti-Stokes region where interference from Raman scattering is negligibly small. Of note, 13 568 Raman spectra measured from different points of 19 living yeast cells are categorized according to their GFP fluorescence intensities, with the use of a two-component multivariate curve resolution with alternate least squares (MCR-ALS) analysis in the anti-Stokes region. This categorization allows us to know whether or not Raman spectra are taken from mitochondria. Raman spectra specific to mitochondria are obtained by an MCR-ALS analysis in the Stokes region of 1389 strongly GFP positive spectra. Two mitochondria specific Raman spectra have been obtained. The first one is dominated by protein Raman bands and the second by lipid Raman bands, being consistent with the known molecular composition of mitochondria. In addition, the second spectrum shows a strong band of ergosterol at 1602 cm −1 , previously reported as "Raman spectroscopic signature of life ofanti-Stokes Raman spectroscopy, mitochondria, Raman spectroscopic signature of life, Schizosaccharomyces pombe, simultaneous Raman/GFP microspectroscopy, yeast

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“…In these works, researchers have proposed many methods. [ 27–29 ] For instance, Lednev et al combined Raman and LIBS by double pulse laser, [ 27 ] in which one is for getting LIBS spectra and the other is for getting Raman spectra. Choi et al detected the Raman and LIBS signal simultaneously from focused position and non‐focused position using a single pulse.…”

Section: Introductionmentioning

confidence: 99%

“…[ 28 ] Syvilay et al used more than one spectrometer and laser to build a hybrid system. [ 29 ] However, these methods only focused on how to get these two kinds of spectra more conveniently. Recently also some works focused on how to merge LIBS spectra and Raman spectra in classification.…”

Section: Introductionmentioning

confidence: 99%

Feature‐level fusion of laser‐induced breakdown spectroscopy and Raman spectroscopy for improving support vector machine in clinical bacteria identification

Teng

Wang

Cui

et al. 2021

J Raman Spectroscopy

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In clinical field, the diagnosis of many diseases and their development stages depend on the detection of the corresponding bacteria. Raman spectroscopy and laser‐induced breakdown spectroscopy (LIBS) are two novel spectral diagnostic technologies for clinical bacteria identification. Both of them have been used in clinical detection combined with optimized support vector machine (SVM). In this paper, two feature‐level fusion methods (before feature selection fusion [BFSF] and after feature selection fusion [AFSF]) were proposed to improve the performance of SVM classifier and reduce the analyzing time (including the parameter tuning, model training, and testing time) simultaneously by combining data of LIBS and Raman spectroscopy. Using the most important 10 feature lines as the inputs of the optimized classifier, the analyzing time could be reduced to 1 to 2 min and the correct classification rate (CCR) achieved 95.67%. Without optimizing SVM parameters, the two proposed methods could achieve rapid and accurate classification of pathogenic bacteria further. The AFSF method showed better results with less fusion features while the BFSF method achieved higher CCR at 100% with more features. Both two methods costed around 0.2 s for analysis. These indicate that the proposed feature‐level fusion methods can improve the performance of SVM for bacteria detection. Maintaining the highest diagnostic accuracy, they can achieve the minimum analyzing time.

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Laser-induced emission, fluorescence and Raman hybrid setup: A versatile instrument to analyze materials from cultural heritage

Cited by 13 publications

References 13 publications

A study of potential laser-induced degradation in remote standoff Raman spectroscopy for wall paintings

A study of potential laser-induced degradation in remote standoff Raman spectroscopy for wall paintings

Organelle specific simultaneous Raman/green fluorescence protein microspectroscopy for living cell physicochemical studies

Feature‐level fusion of laser‐induced breakdown spectroscopy and Raman spectroscopy for improving support vector machine in clinical bacteria identification

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