High angular-resolution automated visible-wavelength scanning angle Raman microscopy

Lesoine, Michael D.; Bobbitt, Jonathan M.; Zhu, Shaobin; Fang, Ning; Smith, Emily A.

doi:10.1016/j.aca.2014.07.040

Cited by 5 publications

(5 citation statements)

References 30 publications

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“…Similar trends are observed for sample 3‐Bi (Figure S2A) and sample 3‐Tri (Figure S3A). These representative calculated results suggest that it should be feasible to use SA Raman spectroscopy, with a signal that is proportional to the electric field intensity, to measure total film thickness as well as the location of polymer interfaces for both bilayer and trilayer films.…”

Section: Resultsmentioning

confidence: 90%

“…This way, the prism does not apply any pressure to the film or alter the film. A home‐built instrument, previously reported by Lesoine et al, was used to collect SA Raman spectra . A 532‐nm excitation source (Coherent, Santa Clara, CA) set to s‐polarized light was directed onto a sapphire prism by coupling the source into a polarization maintaining single mode fiber (Thorlabs, Newton, NJ).…”

Section: Methodsmentioning

confidence: 99%

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Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

Bobbitt

Smith

2017

J Raman Spectroscopy

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There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations for multilayer polymer films, and scanning angle (SA) Raman spectroscopy in combination with appropriate data models can provide this information. A SA Raman spectroscopy method was developed to measure the chemical composition of multilayer polymer waveguide films and to extract the location of buried interfaces between polymer layers with 7‐ to 80‐nm axial spatial resolution. The SA Raman method acquires Raman spectra as the incident angle of light upon a prism‐coupled thin film is scanned. Six multilayer films consisting of poly(methyl methacrylate)/polystyrene or poly(methyl methacrylate)/polystyrene/poly(methyl methacrylate) were prepared with total thicknesses ranging from 330 to 1,260 nm. The interface locations were varied by altering the individual layer thicknesses between 140 and 680 nm. The Raman amplitude ratio of the 1,605‐cm−1 peak for polystyrene and 812‐cm−1 peak for poly(methyl methacrylate) was used in calculations of the electric field intensity within the polymer layers to model the SA Raman data and extract the total thickness and interface locations. There is an average 8% and 7% difference in the measured thickness between the SA Raman and profilometry measurements for bilayer and trilayer films, respectively.

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Section: Resultsmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

Bobbitt

Smith

2017

J Raman Spectroscopy

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“…Furthermore, the multidimensionality of the data (cone diameter and intensity and Raman scattering as a function of incident angle) provides the ability to measure more sample properties compared to either SPR or Raman scattering techniques alone. This is highlighted by our related previous work using a technique called scanning angle Raman spectroscopy, [37][38][39][40][41][42][43][44][45] whereby the incident light is scanned over a wide range of angles while simultaneously collecting the reflected light from the prism side and Raman scattering on the sample side of the interface. Scanning angle Raman spectroscopy (in the absence of a gold film) was used to identify buried interfaces in a multi-layered system with ~10s of nanometer spatial resolution.…”

Section: Figmentioning

confidence: 99%

Combined measurement of directional Raman scattering and surface-plasmon-polariton cone from adsorbates on smooth planar gold surfaces

Nyamekye

Weibel

Bobbitt

et al. 2018

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Directional-surface-plasmon-coupled Raman scattering (directional RS) has the combined benefits of surface plasmon resonance and Raman spectroscopy, and provides the ability to measure adsorption and monolayer-sensitive chemical information. Directional RS is performed by optically coupling a 50 nm gold film to a Weierstrass prism in the Kretschmann configuration and scanning the angle of the incident laser under total internal reflection. The collected parameters on the prism side of the interface include a full surface-plasmon-polariton cone and the full Raman signal radiating from the cone as a function of incident angle. An instrument for performing directional RS and a quantitative study of the instrumental parameters are herein reported. To test the sensitivity and quantify the instrument parameters, self-assembled monolayers and 10 to 100 nm polymer films are studied. The signals are found to be well-modeled by two calculated angle-dependent parameters: three-dimensional finite-difference time-domain calculations of the electric field generated in the sample layer and projected to the far-field, and Fresnel calculations of the reflected light intensity. This is the first report of the quantitative study of the full surface-plasmon-polariton cone intensity, cone diameter, and directional Raman signal as a function of incident angle. We propose that directional RS is a viable alternative to surface plasmon resonance when added chemical information is beneficial.

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“…Monolayer sensitivity has been achieved using various TIR Raman formats (Figure 9). [186][187][188][189] While the TIR enhancement is typically less than the SERS enhancement, the TIR Raman signal is very reproducible, well modeled and does not require a roughened metal substrate. Also, the TIR Raman signal is collected over a longer distance than is possible with SERS, so the entire membrane and associated cytoskeleton can be probed.…”

Section: Total Internal Reflection (Tir) Raman Spectroscopymentioning

confidence: 99%

Optical Imaging of the Nanoscale Structure and Dynamics of Biological Membranes

2018

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Biological membranes serve as the fundamental unit of life, allowing the compartmentalization of cellular contents into subunits with specific functions. The bilayer structure, consisting of lipids, proteins, small molecules, and sugars, also serves many other complex functions in addition to maintaining the relative stability of the inner compartments. Signal transduction, regulation of solute exchange, active transport, and energy transduction through ion gradients all take place at biological membranes, primarily with the assistance of membrane proteins. For these functions, membrane structure is often critical. The fluidmosaic model introduced by Singer and Nicolson in 1972 evokes the dynamic and fluid nature of biological membranes.(1) According to this model, integral and peripheral proteins are oriented in a viscous phospholipid bilayer. Both proteins and lipids can diffuse laterally through the two-dimensional structure. Modern experimental evidence has shown, however, that the structure of the membrane is considerably more complex; various domains in the biological membranes, such as lipid rafts and confinement regions, form a more complicated molecular organization. The proper organization and dynamics of the membrane components are critical for the function of the entire cell. For example, cell signaling is often initiated at biological membranes and requires receptors to diffuse and assemble into complexes and clusters, and the resulting downstream events have consequences throughout the cell. Revealing the molecular level details of these signaling events is the foundation to understanding numerous unsolved questions regarding cellular life.

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High angular-resolution automated visible-wavelength scanning angle Raman microscopy

Cited by 5 publications

References 30 publications

Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

Combined measurement of directional Raman scattering and surface-plasmon-polariton cone from adsorbates on smooth planar gold surfaces

Optical Imaging of the Nanoscale Structure and Dynamics of Biological Membranes

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