Remote high-sensitivity Raman spectroscopy with fiber optics, diode lasers, and CCD spectrometers

1992 ◽  
Author(s):  
Richard L. McCreery
Keyword(s):  
Raman Spectroscopy ◽  
Fiber Optics ◽  
Diode Lasers ◽  
High Sensitivity

Remote, Long-Pathlength Cell for High-Sensitivity Raman Spectroscopy

1987 ◽  
Vol 41 (1) ◽  
pp. 126-130 ◽  
Author(s):  
Scott D. Schwab ◽  
Richard L. McCreery
Keyword(s):  
Fiber Optics ◽  
Laser Light ◽  
Capillary Tube ◽  
High Sensitivity ◽  
Sample Tube ◽  
Increased Sensitivity ◽  
Sampling Systems ◽  
Power Densities ◽  
Objective Being ◽  
Focused Beam

Fiber optics were used to interface a Raman spectrometer to a long (1 m) sample tube, with the objective being increased sensitivity. Internal reflection of the laser light and the Raman scatter within the sample tube permitted a long solution length to be sampled, increasing the Raman sensitivity by factors of 30–50 over conventional capillary tube sampling systems. In addition, the sample was subjected to much lower power densities than with systems employing a focused beam, thus minimizing radiation damage. Detection limits of 10−9 to 10−8 M were achieved for resonance Raman scatterers, and normal Raman scatterers could be detected at the 1 × 10−5 M level.

scholarly journals Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski
Keyword(s):  
Raman Spectroscopy ◽  
Cell Walls ◽  
Structural Changes ◽  
Spatial Information ◽  
Technological Development ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Plant Tissues ◽  
Wide Range ◽  
Identification Technique

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.

scholarly journals 2D Propagation Simulation of Variation Parameters of U-shape Fiber Optic

2020 ◽  
Vol 10 (2) ◽  
pp. 153-158
Keyword(s):  
Fiber Optics ◽  
Power Flow ◽  
Fiber Optic ◽  
Power Transmission ◽  
Simulation Analysis ◽  
Reducing Power ◽  
High Sensitivity ◽  
Curvature Radius ◽  
Sensor Applications ◽  
Core Fiber

Fiber optic has extraordinary properties and is suitable in sensor applications due to its special potential. Currently, macro bending characteristics of newly developed hetero core fiber optic element are designed and evaluated. This paper presents the preliminary results obtained from the numerical simulation analysis of the bending sensitivity of U-shape fiber optics toward the 2D electromagnetic wave in terms of mesh, curvature radius, core fiber size, and turn number. Fiber optics with core sizes of 4, 9, 50, and 62.5 μm were designed. In addition, the combination of core diameters 50-4-50, 50-9-50, 62.5-4-62.5, and 62.5-9-62.5 μm is evaluated to compare the outcome of transmission power in terms of hetero core structure of fiber optic. Simulation is performed using COMSOL Multiphysics simulation tool. The developed U-shape fiber optic is designed to sense the distortion of reducing power transmission by comparing input and output power. Results show that the selected mesh depends on the size of geometry bending fiber optics, and fine and finer mesh is the best for U-shape fiber optic. Furthermore, the power flow on the fiber decreases with the decreasing curvature radius and increasing turn number. The fiber with a core size combination of 62.5–4–62.5 um has high sensitivity in terms of loss. The attained results possess higher potential in the field of sensor applications, such as displacement, strain, pressure, and monitoring respiration, on human body. This study serves as a basis for further investigation of nanomaterial coating on fiber optics, thereby enhancing its credibility for sensing.

scholarly journals Ultrahigh sensitive Raman spectroscopy for subnanoscience: Direct observation of tin oxide clusters

2019 ◽  
Vol 5 (12) ◽  
pp. eaax6455 ◽  
Author(s):  
Akiyoshi Kuzume ◽  
Miyu Ozawa ◽  
Yuansen Tang ◽  
Yuki Yamada ◽  
Naoki Haruta ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Tin Oxide ◽  
Density Functional ◽  
Rational Design ◽  
High Sensitivity ◽  
Density Functional Theory Calculations ◽  
Surface Enhanced Raman Spectroscopy ◽  
Atomic Scale ◽  
Practical Applications ◽  
Surface Enhanced Raman

Subnanometric metal clusters exhibit anomalous catalytic activity, suggesting innovative applications as next-generation materials, although identifying and characterizing these subnanomaterials in atomic detail remains a substantial challenge because of the severely weak signal intensity for the conventional analytical methods. Here, we report a subnanosensitive vibrational technique established based on the surface-enhanced Raman spectroscopy, demonstrating the first-ever detailed vibrational characterization of subnanomaterials. Furthermore, combining with density functional theory calculations, we reveal that inherent surface structures of the tin oxide subnanoclusters determine the size-specific spectral and catalytic characteristics of these clusters. The high-sensitivity characterization methodology elaborated here can provide a comprehensive understanding of the chemical and structural natures of subnanomaterials, which facilitate the rational design of subnanomaterials on the atomic scale for practical applications, such as in catalysts, biosensors, and electronics.

The utilization of diode lasers for Raman spectroscopy

1995 ◽  
Vol 51 (11) ◽  
pp. 1779-1799 ◽  
Author(s):  
S.M. Angel ◽  
M. Carrabba ◽  
T.F. Cooney
Keyword(s):  
Raman Spectroscopy ◽  
Diode Lasers

Red-Excitation Dispersive Raman Spectroscopy is a Suitable Technique for Solid-State Analysis of Respirable Pharmaceutical Powders

2005 ◽  
Vol 59 (3) ◽  
pp. 286-292 ◽  
Author(s):  
Reinhard Vehring
Keyword(s):  
Raman Spectroscopy ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Instrument Design ◽  
Background Suppression ◽  
Pharmaceutical Powders ◽  
Limit Of Quantification ◽  
Mass Fractions ◽  
Suitable Technique ◽  
Spray Dried

Dispersive Raman spectroscopy with excitation by a red diode laser is suitable for quantitative crystallinity measurements in powders for pulmonary drug delivery. In spray-dried mixtures of salmon calcitonin and mannitol, all three crystalline polymorphs of mannitol and amorphous mannitol were unambiguously identified and their mass fractions were measured with a limit of quantification of about 5%. The instrument design offered high sensitivity and adequate background suppression, resulting in a low limit of detection in the range of 0.01% to 1%. This spectroscopy method has significant advantages over established techniques regarding specificity, sensitivity, and sample requirements.

Stress imaging in structural challenging MEMS with high sensitivity using micro-Raman spectroscopy

2017 ◽  
Vol 79 ◽  
pp. 104-110 ◽  
Author(s):  
Peter Meszmer ◽  
Raul D. Rodriguez ◽  
Evgeniya Sheremet ◽  
Dietrich R.T. Zahn ◽  
Bernhard Wunderle
Keyword(s):  
Raman Spectroscopy ◽  
High Sensitivity ◽  
Stress Imaging ◽  
Micro Raman Spectroscopy

High Sensitivity Vibrational Mode Detection with Doppler Raman Spectroscopy

2018 ◽  
Author(s):  
David R. Smith ◽  
Jeffrey J. Field ◽  
David Winters ◽  
Scott Domingue ◽  
Jesse W. Wilson ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Vibrational Mode ◽  
High Sensitivity ◽  
Mode Detection
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