The mechanism of ArF laser-induced fluorescence of dense plume matter

2016 ◽  
Vol 31 (12) ◽  
pp. 2363-2374 ◽  
Author(s):  
Xiaochun Wang ◽  
Zhengyu Huang ◽  
Po-Chun Chu ◽  
Yue Cai ◽  
Kelvin S. Y. Leung ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Laser Induced Fluorescence ◽  
Emission Lines ◽  
Excitation Wavelength ◽  
Energy Structure ◽  
Arf Laser

In pulsed laser ablative sampling, photoexcitation of the nascent plume can be nonselective because the energy structure is band-like. As the plume disperses, the bands taper to discrete levels and analyte emission lines become narrow. Multi-analyte fluorescence at a single excitation wavelength is therefore possible.

scholarly journals A spectral library for laser-induced fluorescence analysis as a tool for rare earth element identification

2020 ◽  
Author(s):  
Margret C. Fuchs ◽  
Jan Beyer ◽  
Sandra Lorenz ◽  
Suchinder Sharma ◽  
Axel D. Renno ◽  
...  
Keyword(s):  
Rare Earth ◽  
Emission Line ◽  
High Energy ◽  
Laser Induced Fluorescence ◽  
Training Data ◽  
Emission Lines ◽  
Excitation Wavelength ◽  
Spectral Library ◽  
Energy Excitation ◽  
532 Nm

Abstract. With the recurring interest on rare-earth elements (REE), laser-induced fluorescence (LiF) may provide a powerful tool for their rapid and accurate identification at different stages along their value chain. Applications to natural materials such as rocks could complement the spectroscopy-based toolkit for innovative, non-invasive exploration technologies. However, the diagnostic assignment of detected emission lines to individual REE remains challenging, because of the complex composition of natural rocks in which they can be found. The resulting mixed spectra and the large amount of data generated demand for automated approaches of data evaluation, especially in mapping applications such as drill core scanning. LiF reference data provide the solution for robust REE identification, yet they usually remain in the form of tables of published emission lines. We show that a complete reference spectra library could open manifold options for innovative automated analysis. We present a library of high-resolution LiF reference spectra using the Smithsonian rare-earth phosphate standards for electron microprobe analysis.We employ three standard laser wavelengths (325 nm, 442 nm, 532 nm) to record representative spectra in the UV-visible to near-infrared spectral range (340–1080 nm). Excitation at all three laser wavelengths yielded characteristic spectra with distinct REE-related emission lines for EuPO4, TbPO4, DyPO4 and YbPO4. In the other samples, the high-energy excitation at 325 nm caused unspecific, broadband defect emissions. Here, lower energy laser excitation showed successful for suppressing non-REE-related emission. At 442 nm excitation, REE-reference spectra depict the diagnostic emission lines of PrPO4, SmPO4 and ErPO4. For NdPO4 and HoPO4 most efficient excitation was achieved with 532 nm. Our results emphasise on the possibility of selective REE excitation by changing the excitation wavelength according to the suitable conditions for individual REEs. Our reference spectra provide a database for transparent and reproducible evaluation of REE-bearing rocks. The LiF spectral library is available at https://zenodo.org/ and the registered DOI: http://doi.org/10.5281/zenodo.4054606 (Fuchs et al., 2020). It gives access to traceable data for manifold further studies on comparison of emission line positions, emission line intensity ratios and splitting into emission line sub-levels or can be used as reference or training data for automated approaches of component assignment.

scholarly journals Remote Laser Induced Fluorescence of Soils and Rocks

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 411
Author(s):  
Vasily N. Lednev ◽  
Alexey F. Bunkin ◽  
Sergey M. Pershin ◽  
Mikhail Ya. Grishin ◽  
Diana G. Artemova ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Fluorescence Spectra ◽  
Space Exploration ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Extraterrestrial Life ◽  
Future Space ◽  
Lidar Sensing ◽  
First Time ◽  
Different Soils

The laser induced fluorescence spectroscopy was systematically utilized for remote sensing of different soils and rocks for the first time, to the best of our knowledge. Laser induced fluorescence spectroscopy measurements were carried out by the developed nanosecond LIDAR instrument with variable excitation wavelength (355, 532 and 1064 nm). LIDAR sensing of different Brazil soil samples have been carried out in order to construct a spectral database. The laser induced fluorescence spectra interpretation for different samples has been discussed in detail. The perspectives of LIDAR sensing of organic samples deposited at soils and rock have been discussed including future space exploration missions in the search for extraterrestrial life.

scholarly journals Experimental analysis on the optimal excitation wavelength for fine-grained identification of refined oil pollutants on water surface based on laser-induced fluorescence

2021 ◽  
Author(s):  
Ming Xie ◽  
Yunpeng Jia ◽  
Ying Li ◽  
Xiaohua Cai ◽  
Kai Cao
Keyword(s):  
Oil Spill ◽  
Theoretical Basis ◽  
Water Surface ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Refined Oil ◽  
Fine Grained ◽  
Optimal Excitation ◽  
Oil Spill Identification

Abstract Laser-induced fluorescence (LIF) is an effective, all-weather oil spill identification method that has been widely applied for oil spill monitoring. However, the distinguishability on oil types is seldom considered while selecting excitation wavelength. This study is intended to find the optimal excitation wavelength for fine-grained classification of refined oil pollutants using LIF by comparing the distinguishability of fluorometric spectra under various excitation wavelengths on some typical types of refined-oil samples. The results show that the fluorometric spectra of oil samples significantly vary under different excitation wavelengths, and the four types of oil applied in this study are most likely to be distinguished under the excitation wavelengths of 395 nm and 420 nm. This study is expected to improve the ability of oil types identification using LIF method without increasing time or other cost, and also provides theoretical basis for the development of portable LIF devices for oil spill identification.

Laser-induced fluorescence (LIF) of lignin and lignin model compounds in Raman spectroscopy

Holzforschung ◽  
2013 ◽  
Vol 67 (5) ◽  
pp. 531-538 ◽  
Author(s):  
Anni Lähdetie ◽  
Paula Nousiainen ◽  
Jussi Sipilä ◽  
Tarja Tamminen ◽  
Anna-Stiina Jääskeläinen
Keyword(s):  
Raman Spectroscopy ◽  
Structural Information ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Raman Signal ◽  
Model Compounds ◽  
Worst Case ◽  
Lignin Model Compounds ◽  
Key Factor ◽  
Lignin Model

Abstract Raman spectroscopy is a technique that provides structural information on lignin and other components of wood and pulp in situ. However, especially lignin-containing samples may produce laser-induced fluorescence (LIF) that overlaps with Raman bands. In the worst case, this background signal can overwhelm the weaker Raman signal completely. In this study, the LIF of lignin was investigated with the excitation wavelength 532 nm applied in Raman spectroscopy to clarify the correlations between lignin structure and LIF intensity. Raman spectroscopic analyses with lignin model compounds illustrated that the 5-5′ structures induce LIF. It was also shown that the intensity of LIF was significantly less intense when the 5-5′ model compound was structurally rigid (as in dibenzodioxocin) compared with the flexible simple counterpart. The comparison between the free phenolic model compounds with the methylated analogue showed that the presence of the free phenolic structure was not a prerequisite for LIF. It was thus concluded that the conformation of the molecule is the key factor with respect to fluorescence. The role of conformational aspects was further investigated by comparing wood with chemical pulps and isolated lignins.

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