Confocal Raman Line-Scanned Imaging of Complex Geological and Histological Thin Sections

Chemical imaging of complex multi-component materials has important potential for the analyst in many fields of research. Raman imaging is of particular interest for several reasons. The Raman spectra contain detailed information on chemical species and crystalline phase. Because the Raman effect is excited by optical radiation, the spatial resolution, which is proportional to the wavelength of the light, is better than 1 μm. and with near field optical techniques currently under development, there is potential for even higher spatial resolution in the chemical image.The methods used to produce an image fall into essentially two categories - global imaging and confocal mapping. When creating global images, a large area of the sample is bathed in laser light. The light scattered by the sample is filtered to select a Raman band, and then that light is used to create an image of the sample on a two-dimensional detector.

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Nanoscale Spatial Resolution in Far-Field Raman Imaging Using Hyperspectral Unmixing in Combination with Positivity Constrained Super-Resolution

Applied Spectroscopy ◽

10.1177/0003702820920688 ◽

2020 ◽

Vol 74 (7) ◽

pp. 780-790

Author(s):

Dominik J. Winterauer ◽

Daniel Funes-Hernando ◽

Jean-Luc Duvail ◽

Saïd Moussaoui ◽

Tim Batten ◽

...

Keyword(s):

Raman Spectroscopy ◽

Spatial Resolution ◽

Single Channel ◽

Near Field ◽

Resolution Enhancement ◽

Super Resolution ◽

Resolving Power ◽

Far Field ◽

Hyperspectral Unmixing ◽

Better Than

This work introduces hyper-resolution (HyRes), a numerical approach for spatial resolution enhancement that combines hyperspectral unmixing and super-resolution image restoration (SRIR). HyRes yields a substantial increase in spatial resolution of Raman spectroscopy while simultaneously preserving the undistorted spectral information. The resolving power of this technique is demonstrated on Raman spectroscopic data from a polymer nanowire sample. Here, we demonstrate an achieved resolution of better than 14 nm, a more than eightfold improvement on single-channel image-based SRIR and [Formula: see text] better than regular far-field Raman spectroscopy, and comparable to near-field probing techniques.

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Nanoscale chemical imaging by photoinduced force microscopy

Science Advances ◽

10.1126/sciadv.1501571 ◽

2016 ◽

Vol 2 (3) ◽

pp. e1501571 ◽

Cited By ~ 110

Author(s):

Derek Nowak ◽

William Morrison ◽

H. Kumar Wickramasinghe ◽

Junghoon Jahng ◽

Eric Potma ◽

...

Keyword(s):

Self Assembly ◽

Low Cost ◽

Near Field ◽

Chemical Species ◽

Real Space ◽

Chemical Imaging ◽

Chemical Components ◽

Chemical Information ◽

Force Microscopy ◽

The Individual

Correlating spatial chemical information with the morphology of closely packed nanostructures remains a challenge for the scientific community. For example, supramolecular self-assembly, which provides a powerful and low-cost way to create nanoscale patterns and engineered nanostructures, is not easily interrogated in real space via existing nondestructive techniques based on optics or electrons. A novel scanning probe technique called infrared photoinduced force microscopy (IR PiFM) directly measures the photoinduced polarizability of the sample in the near field by detecting the time-integrated force between the tip and the sample. By imaging at multiple IR wavelengths corresponding to absorption peaks of different chemical species, PiFM has demonstrated the ability to spatially map nm-scale patterns of the individual chemical components of two different types of self-assembled block copolymer films. With chemical-specific nanometer-scale imaging, PiFM provides a powerful new analytical method for deepening our understanding of nanomaterials.

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High-spatial resolution resistivity mapping of large-area YBCO films by a near-field millimeter-wave microscope

IEEE Transactions on Microwave Theory and Techniques ◽

10.1109/22.508246 ◽

1996 ◽

Vol 44 (7) ◽

pp. 1390-1392 ◽

Cited By ~ 40

Author(s):

M. Golosovsky ◽

A. Galkin ◽

D. Davidov

Keyword(s):

Millimeter Wave ◽

Spatial Resolution ◽

High Spatial Resolution ◽

Near Field ◽

Large Area ◽

Ybco Films

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The Application of High Resolution Chemical Imaging Techniques for Butyl Rubber Blends

Rubber Chemistry and Technology ◽

10.5254/1.3548209 ◽

2008 ◽

Vol 81 (2) ◽

pp. 265-275 ◽

Cited By ~ 3

Author(s):

Donald A. Winesett ◽

Andy H. Tsou

Keyword(s):

High Resolution ◽

Sample Preparation ◽

Spatial Resolution ◽

Secondary Ion Mass Spectrometry ◽

Imaging Techniques ◽

Chemical Species ◽

Chemical Imaging ◽

Rubber Blends ◽

Tof Sims ◽

Good Spatial Resolution

Abstract Atomic Force Microscopy (AFM), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) imaging, and Scanning Transmission X-ray Microscopy (STXM) are applied to identical series of elastomeric blends to evaluate the relative strengths and weaknesses of each imaging technique. AFM is a high resolution, high contrast technique with straight forward sample preparation that derives contrast through elastic modulus variations, but, when used in a conventional mode, has limited chemical specificity. ToF-SIMS imaging can map phases, detect trace levels (ppm) of additives and other chemical species based on relatively straight forward sample preparation, but has poorer spatial resolution and the instrumentation is expensive. STXM has excellent chemical specificity and good spatial resolution but is only available at a beamline and requires more advanced sample preparation. Each technique will be overviewed briefly and relative merits of each will be compared based on evaluations of some commercially relevant rubber blend materials.

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Near Field Scanning Optical Microscopy and Spectroscopy of Electronic Materials and Structures

MRS Proceedings ◽

10.1557/proc-406-183 ◽

1995 ◽

Vol 406 ◽

Cited By ~ 4

Author(s):

W. M. Duncan

Keyword(s):

Spatial Resolution ◽

Electronic Materials ◽

Near Field ◽

Optical Microscope ◽

Chemical Information ◽

Scanning Optical Microscopy ◽

Thickness Variations ◽

Physical And Chemical ◽

Near Field Scanning ◽

Better Than

AbstractA Near Field Scanning Optical Microscope (NSOM) with spectroscopic capability is applied to imaging semiconductor and microelectronic structures. NSOM combined with spectroscopic analysis provides physical and chemical information of thin films and defects with ultra high spatial resolution. We have studied epitaxial and bulk samples and partially fabricated SiO2/Si CMOS structures to investigate the spatial resolution and imaging modes of NSOM. Reflected intensity contrast in NSOM yields images of defect networks in InGaAs/InAlAs/GaAs epitaxial layers and shows thickness variations in SiO2 films on Si. Surface topological changes observed in NSOM demonstrate a spatial resolution of significantly better than 0.25 μm. Fluorescence imaging is examined for chemically identifying materials and defects.

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Generalized Heterodyne Configurations for Photo-induced Force Microscopy

10.26434/chemrxiv.9633407 ◽

2019 ◽

Author(s):

Le Wang ◽

Devon Jakob ◽

Haomin Wang ◽

Alexis Apostolos ◽

Marcos M. Pires ◽

...

Keyword(s):

Spatial Resolution ◽

Repetition Rate ◽

Modulation Frequency ◽

High Harmonic ◽

Chemical Imaging ◽

Heterodyne Detection ◽

Force Microscopy ◽

Wide Range ◽

The Difference ◽

Afm Cantilever

<div>Infrared chemical microscopy through mechanical probing of light-matter interactions by atomic force microscopy (AFM) bypasses the diffraction limit. One increasingly popular technique is photo-induced force microscopy (PiFM), which utilizes the mechanical heterodyne signal detection between cantilever mechanical resonant oscillations and the photo induced force from light-matter interaction. So far, photo induced force microscopy has been operated in only one heterodyne configuration. In this article, we generalize heterodyne configurations of photoinduced force microscopy by introducing two new schemes: harmonic heterodyne detection and sequential heterodyne detection. In harmonic heterodyne detection, the laser repetition rate matches integer fractions of the difference between the two mechanical resonant modes of the AFM cantilever. The high harmonic of the beating from the photothermal expansion mixes with the AFM cantilever oscillation to provide PiFM signal. In sequential heterodyne detection, the combination of the repetition rate of laser pulses and polarization modulation frequency matches the difference between two AFM mechanical modes, leading to detectable PiFM signals. These two generalized heterodyne configurations for photo induced force microscopy deliver new avenues for chemical imaging and broadband spectroscopy at ~10 nm spatial resolution. They are suitable for a wide range of heterogeneous materials across various disciplines: from structured polymer film, polaritonic boron nitride materials, to isolated bacterial peptidoglycan cell walls. The generalized heterodyne configurations introduce flexibility for the implementation of PiFM and related tapping mode AFM-IR, and provide possibilities for additional modulation channel in PiFM for targeted signal extraction with nanoscale spatial resolution.</div>

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Mapping and Monitoring of the Land Use/Cover Changes in the Wider Area of ltanos, Crete, Using Very High Resolution EO Imagery With Specific Interest in Archaeological Sites

10.31219/osf.io/3vrth ◽

2019 ◽

Cited By ~ 1

Author(s):

Sawyer Reid stippa ◽

George Petropoulos ◽

Leonidas Toulios ◽

Prashant K. Srivastava

Keyword(s):

High Resolution ◽

Spatial Resolution ◽

Satellite Images ◽

Archaeological Site ◽

Digital Photography ◽

Archaeological Sites ◽

Large Area ◽

High Resolution Imagery ◽

Site Mapping ◽

Rule Sets

Archaeological site mapping is important for both understanding the history as well as protecting them from excavation during the developmental activities. As archaeological sites generally spread over a large area, use of high spatial resolution remote sensing imagery is becoming increasingly applicable in the world. The main objective of this study was to map the land cover of the Itanos area of Crete and of its changes, with specific focus on the detection of the landscape’s archaeological features. Six satellite images were acquired from the Pleiades and WorldView-2 satellites over a period of 3 years. In addition, digital photography of two known archaeological sites was used for validation. An Object Based Image Analysis (OBIA) classification was subsequently developed using the five acquired satellite images. Two rule-sets were created, one using the standard four bands which both satellites have and another for the two WorldView-2 images their four extra bands included. Validation of the thematic maps produced from the classification scenarios confirmed a difference in accuracy amongst the five images. Comparing the results of a 4-band rule-set versus the 8-band showed a slight increase in classification accuracy using extra bands. The resultant classifications showed a good level of accuracy exceeding 70%. Yet, separating the archaeological sites from the open spaces with little or no vegetation proved challenging. This was mainly due to the high spectral similarity between rocks and the archaeological ruins. The satellite data spatial resolution allowed for the accuracy in defining larger archaeological sites, but still was a difficulty in distinguishing smaller areas of interest. The digital photography data provided a very good 3D representation for the archaeological sites, assisting as well in validating the satellite-derived classification maps. All in all, our study provided further evidence that use of high resolution imagery may allow for archaeological sites to be located, but only where they are of a suitable size archaeological features.

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