نتائج البحث - "Raman microscope"

1

المؤلفون: Mariko Adachi

المصدر: Journal of The Surface Finishing Society of Japan. 72:154-158

مصطلحات موضوعية: Materials science, Laser scanning, business.industry, General Engineering, Optoelectronics, Raman microscope, business

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::36b98a8b8bbd961b553bc47e21d4e5ac
https://doi.org/10.4139/sfj.72.154

2

Signature of Plasmonic Nanostructures Synthesised by Electrical Exploding Wire Technique on Surface-Enhanced Raman Scattering

المؤلفون: Hammed R Mahmood, Fouad G. Hamzah

المصدر: Iraqi Journal of Science. :167-179

الوصف: This work aims to fabricate two types of plasmonic nanostructures by electrical exploding wire (EEW) technique and study the effects of the different morphologies of these nanostructures on the absorption spectra and Surface-Enhanced Raman Scattering (SERS) activities, using Rhodamine 6G as a probe molecule. The structural properties of these nanostructures were examined using X-Ray diffraction (XRD). The morphological properties were examined using field emission scanning electron microscopy (FESEM) and scanning transmission electron microscopy (STEM). The absorption spectra of the mixed R6G laser dye (concentration 1Ã—10-6 M) with prepared nanostructures were examined by double beam UV-Vis Spectrophotometer. The Raman spectra of the R6G mixed with the prepared nanostructures were examined using a Horiba HR Evolution 800 Raman microscope system with an objective lens (50 Ã—). The FESEM and STEM images indicated that the Ag nanoparticles (AgNPs) with 35 nm average particle sizes were decorated on the surface of the AgNWs and the PDA layer by EEW technique, forming AgNW@AgNPs and AgNW@PDA@AgNPs nanostructures. The results indicated that the increased intensities of the absorption spectra peaks and the SERS arise from the hot spots and the roughness of the surface of nanostructures. The SERS enhancement factor of R6G (1Ã—10-6 M) was reached at 2.3Ã—107 and 2.5Ã—107, at the wave number of 1650 cm-1, for the AgNW@AgNPs and AgNW@PDA@AgNPs nanostructures, respectively, after being excited by (Î»exc. = 532 nm) laser source. It can be concluded that the AgNW@AgNPs and AgNW@PDA@AgNPs nanostructures were fabricated with an easy and simple way without the need for additional chemical compounds. These nanostructures attained a reliable and sensitive detection and can be utilized in a variety of SERS applications, such as chemical and biological sensors.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::55d52076c7bf8c43b54b74e31cf91f6f
https://doi.org/10.24996/ijs.2021.62.1.16

3

Measurement of lateral and axial resolution of confocal Raman microscope using dispersed carbon nanotubes and suspended graphene

المؤلفون: Shrawan Roy, Jeongyong Kim, Anir S. Sharbirin, Eunji Lee, Youngbum Kim, Lars-Gunnar Ranz, Thomas Dieing

المصدر: Current Applied Physics. 20:71-77

الوصف: A confocal Raman microscope (CRM) facilitates visualization of the spatial distribution of molecular bonds or phonon modes at the submicron level and has been extensively used in the characterization of nanomaterials and devices. The lateral and axial resolution is a key specification that defines the performance of CRM, however, the interpretation of spatial resolution in the literature is often ambiguous, making it often difficult to directly compare Raman images obtained under different conditions. In this report, a convenient and reliable measurement protocol using dispersed carbon nanotubes and suspended graphene as test specimens is proposed to facilitate the determination of the lateral and axial resolutions of a CRM. Spatial resolution values comparable to the results based on Rayleigh criterion calculations were obtained using Raman mapping images of test specimens. This was achieved without the need for complex deconvolution processes or the consideration of an asymmetric dielectric environment.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::75e52604368f99ad692632c0ee35143a
https://doi.org/10.1016/j.cap.2019.10.012

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4

Improved Sensitivity of Surface-Enhanced Raman Scattering with Gold Nanoparticles-Insulator-Metal Sandwich Layers on Flat Sapphire Substrate

المؤلفون: Zhuo Yang, Chao Ping Chen, Wenbing Li, Bo Liu, Xin Tong, Jiali Zhang

المصدر: Nanomaterials
Volume 11
Issue 9
Nanomaterials, Vol 11, Iss 2416, p 2416 (2021)

الوصف: Surface-enhanced Raman scattering (SERS) as a high sensitivity analytical method for molecule detection has attracted much attention in recent research. In this work, we demonstrated an improved SERS substrate, which has the gold nanoparticles randomly distributed on a SiO2 interception layer over a gold thin film layer on the flat sapphire substrate (AuNP/SiO2/Au/Sapphire), over the dispersed gold nanoparticles on a silicon substrate (AuNP/Si), for detection of R6G (1 × 10−6 M) in a Raman microscope. The fabrication of sandwich layers on top of the sapphire substrate involves evaporation of a gold mirror as thick as 100 nm, plasma enhanced chemical vapor deposition of the silica insulator layer 10 nm thick, and evaporation of a thin gold layer 10 nm thick for forming gold nanoparticles. For comparison, a gold thin film with a thickness of 5 nm and 10 nm was evaporated on a silicon substrate, respectively (AuNP/Si), as the reference SERS substrates in the experiment. The AuNP/SiO2/Au/Sapphire substrate demonstrated improved sensitivity in detection of molecules in Raman microscopy, which can enable the molecules to be recognizable at a low laser power as 8.5 × 10−3 mW, 0.017 mW, 0.085 mW, and 0.17 mW for ultrashort exposure time. The simulation of AuNP/SiO2/Au/Sapphire substrate and AuNP/Si substrate, based on the finite-difference time-domain (FDTD) method, explained the improved sensitivity for detection of R6G molecules from the view of classical electromagnetics, and it suggested the optimized size for the gold nanoparticles and the optimized laser wavelength for Raman microscopy for further research.

وصف الملف: application/pdf

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9d6b6524cde279f351f67ba59fe618fb

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5

Femtosecond laser patterned superhydrophobic/hydrophobic SERS sensors for rapid positioning ultratrace detection

المؤلفون: Meng Wang, Xiangyun Gun, Zhixia Zheng, Chunbo Li, Kaichen Xu, Huan Yang, Can Yang, Gihong Pang

المصدر: Optics express. 29(11)

الوصف: Ultratrace molecular detections are vital for precancer diagnosis, forensic analysis, and food safety. Superhydrophobic (SH) surface-enhanced Raman scattering (SERS) sensors are regarded as an ideal approach to improve detection performance by concentrating analyte molecules within a small volume. However, due to the low adhesion of SH surfaces, the analyte droplet is prone to rolling, making it hard to deposit molecules on a predetermined position. Furthermore, the sediment with a very small area on the SH-SERS surface is difficult to be captured even with a Raman microscope. In this study, femtosecond laser fabricated hybrid SH/hydrophobic (SH/HB) surfaces are successfully applied to realize a rapid and highly sensitive SERS detection. By modulating dual surface structures and wetting behaviors, the analyte molecules can be enriched at the edge of HB pattern. This improves the convenience and speed of Raman test. On a hybrid SH/HB SERS substrate with a circular HB pattern at 300-µm-diameter, a femtomolar level (10−14 M) of rhodamine 6G can be detected by using analyte volumes of just 5 µL. The SERS enhancement factor can reach 5.7×108 and a good uniformity with a relative standard deviation of 6.98% is achieved. Our results indicate that the laser fabrication of hybrid SERS sensor offers an efficient and cost-effective approach for ultratrace molecular detection.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::99329c020caa639998194d4fb2b1c7a4
https://pubmed.ncbi.nlm.nih.gov/34154243

6

Absolute quantum advantage in microscopy

المؤلفون: Warwick P. Bowen, Catxere A. Casacio, Kai Barnscheidt, Michael A. Taylor, Boris Hage, Alex Terrasson, Muhammad Waleed, Lars S. Madsen

المصدر: Optical and Quantum Sensing and Precision Metrology.

مصطلحات موضوعية: Photon, Materials science, Microscope, business.industry, law.invention, symbols.namesake, law, Microscopy, Quantum metrology, symbols, Optoelectronics, Raman microscope, business, Raman spectroscopy, Quantum, Squeezed coherent state

الوصف: State-of-the-art microscopes use intense lasers that can severely disturb biological processes, function and viability. This introduces hard limits on performance that only quantum photon correlations can overcome. Here we demonstrate this absolute quantum advantage, achieving signal-to-noise beyond the photodamage-free capacity of conventional microscopy. We achieve this in a coherent Raman microscope, which we use to image molecular bonds within a cell with both quantum-enhanced contrast and sub-wavelength resolution. This allows the observation of nanoscale biological structures that would otherwise not be resolved. Coherent Raman microscopes allow highly selective biomolecular finger-printing in unlabelled specimens, but photodamage is a major roadblock for many applications. By showing that this roadblock can be overcome, our work provides a path towards order-of-magnitude improvements in both sensitivity and imaging speed.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::ead53e3b919710928344a1deaf5977f8
https://doi.org/10.1117/12.2587141

7

Multiline illumination Raman microscopy for rapid cell imaging

المؤلفون: Yasuaki Kumamoto, Kentaro Mochizuki, Katsumasa Fujita

المصدر: Biomedical Imaging and Sensing Conference 2020.

مصطلحات موضوعية: inorganic chemicals, Materials science, business.industry, Confocal, technology, industry, and agriculture, Image processing, macromolecular substances, law.invention, symbols.namesake, Confocal microscopy, law, Microscopy, symbols, Image acquisition, Optoelectronics, Raman microscope, business, Raman spectroscopy, Raman scattering

الوصف: Acceleration of image acquisition rate in Raman microscopy has been required to fully utilize its analytical advantages for biological/medical applications. By introducing the multiple line illumination and parallel spectral detection capability, image acquisition rate in the Raman microscope was improved < 104 times, compared with the conventional confocal Raman. High-resolution spontaneous Raman imaging of cells/tissues was thus enabled with an image acquisition time of a few minutes. Subsequent high-throughput Raman imaging-based analyses were also performed, including multiplex Raman tag imaging, cell classification, microplastic detection.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::a108d734c6259ab192d6b1e5d33a496f
https://doi.org/10.1117/12.2573222

8

Backfolded acoustic phonons as ultrasonic probes in metal-oxide superlattices

المؤلفون: Jarji Khmaladze, F. Lyzwa, Matteo Minola, Bernhard Keimer, K. Fürsich, Benjamin P. P. Mallett, Andrew Chan, Christian Bernhard

المصدر: Physical Review Materials. 4

الوصف: Ultrasonics have been an incisive probe of internal interfaces in a wide variety of systems ranging from stars to solids. For thin-film structures, however, ultrasound is largely ineffective because the signal is dominated by the substrate. Using confocal Raman spectromicroscopy, we show that multiple reflection of sound waves at internal interfaces of a metal-oxide superlattice generates standing waves that are insensitive to the substrate. Such modes had previously been observed only in high-quality superlattices of elemental semiconductors, and their observation in complex metal-oxide heterostructures is testimony to recent progress in this field. We use the high spatial resolution of the Raman microscope to demonstrate the high sensitivity of the mode frequency to atomic-scale thickness variations of the superlattice. Spectroscopy of acoustic standing waves can hence serve as a powerful characterization tool of thin-film structures. In analogy to ultrasound spectroscopy of bulk solids, lineshape analysis of these modes has the potential to yield detailed information about the internal structure of the interfaces as well as the coupling of sound waves to the low-frequency spin, charge, and orbital dynamics in metal-oxide superlattices.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::6194ea1cc283fe720875a2053ebcdc2b
https://doi.org/10.1103/physrevmaterials.4.043606

9

A Miniature Fibre-Optic Raman Probe Fabricated by Ultrafast Laser-Assisted Etching

المؤلفون: Nicholas John Weston, Calum A. Ross, Rainer J. Beck, Brian J. E. Smith, Jonathan D. Shephard, Robert R. Thomson, David Guillaume MacLachlan

المصدر: Micromachines
Volume 11
Issue 2
Micromachines, Vol 11, Iss 2, p 185 (2020)

الوصف: Optical biopsy describes a range of medical procedures in which light is used to investigate disease in the body, often in hard-to-reach regions via optical fibres. Optical biopsies can reveal a multitude of diagnostic information to aid therapeutic diagnosis and treatment with higher specificity and shorter delay than traditional surgical techniques. One specific type of optical biopsy relies on Raman spectroscopy to differentiate tissue types at the molecular level and has been used successfully to stage cancer. However, complex micro-optical systems are usually needed at the distal end to optimise the signal-to-noise properties of the Raman signal collected. Manufacturing these devices, particularly in a way suitable for large scale adoption, remains a critical challenge. In this paper, we describe a novel fibre-fed micro-optic system designed for efficient signal delivery and collection during a Raman spectroscopy-based optical biopsy. Crucially, we fabricate the device using a direct-laser-writing technique known as ultrafast laser-assisted etching which is scalable and allows components to be aligned passively. The Raman probe has a sub-millimetre diameter and offers confocal signal collection with 71.3% ±
1.5% collection efficiency over a 0.8 numerical aperture. Proof of concept spectral measurements were performed on mouse intestinal tissue and compared with results obtained using a commercial Raman microscope.

وصف الملف: application/pdf

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::311afd8dc3405df0fe9b35a7d17b0ca6

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10

A Miniature Fibre-optic Raman Probe Fabricated by Ultrafast Laser Assisted Etching

المؤلفون: Brian J. E. Smith, Rainer J. Beck, David Guillaume MacLachlan, Robert R. Thomson, Jonathan D. Shephard, Calum A. Ross, Nicholas John Weston

مصطلحات موضوعية: Optical fiber, Materials science, business.industry, Optical Biopsy, Signal, optics, law.invention, Numerical aperture, symbols.namesake, Etching (microfabrication), law, symbols, Optoelectronics, Raman microscope, business, Raman spectroscopy, Ultrashort pulse

الوصف: Optical biopsy describes a range of medical procedures in which light is used to investigate disease in the body, often in hard-to-reach regions via optical fibres. Optical biopsies can reveal a multitude of diagnostic information to aid therapeutic diagnosis and treatment with higher specificity and shorter delay than traditional surgical techniques. One specific type of optical biopsy relies on Raman spectroscopy to differentiate tissue types at the molecular level and has been used successfully to stage cancer. However, complex micro-optical systems are usually needed at the distal-end to optimise the signal-to-noise properties of the Raman signal collected. Manufacturing these devices remains a critical challenge, particularly in a way suitable for large scale adoption. In this paper, we describe a novel fibre-fed micro-optic system designed for efficient signal delivery and collection during a Raman spectroscopy based optical biopsy. Crucially, we fabricate the device using a direct-laser-writing technique known as ultrafast laser assisted etching which is scalable and allows components to be aligned passively. The Raman probe has a sub-millimetre diameter and offers confocal signal collection with 71.3 ± 1.5% collection efficiency over a 0.8 numerical aperture. Proof of concept spectral measurements were performed on mouse intestinal tissue and compared with results obtained using a commercial Raman microscope.

وصف الملف: application/pdf

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::12b632a3adccd69d3f36da1b4b9264fa

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