Polarized measurements in Raman microscopy

Lagugné‐Labarthet, François

doi:10.1039/b605698a

Cited by 13 publications

(6 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…† The protocol for ascribing the electrical field vector distribution to the topography variations is described elsewhere. [25][26][27][28]46,47 Upon exposure of the polymer films to irradiation with AE451 interference patterns and the simultaneous acquisition of the topography development, the polarization was switched to the PP interference pattern, the position of irradiation change is marked by thick white arrows in Fig. 4.…”

Section: Reversible Switching Of the Polymer Film Topography During Changing Of Irradiation Conditionsmentioning

confidence: 99%

“…When incoming light has a local electric field vector distribution/modulation in terms of either intensity or polarization, achieved by using, for instance, two beam interference lithography, the formation of local phases of aligned azobenzenes and their coupling to the polymer matrix result in anisotropic photo-mechanical stress large enough to induce macroscopic deformation of the polymer material. [26][27][28] Recently it was reported that the stress within the polymer material could be as high as several hundreds of MPa. 29,30 Large opto-mechanical stress generated within polymer films is manifested by local scission of covalent bonds when polymer chains are covalently attached to a solid surface.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A comparative study of photoinduced deformation in azobenzene containing polymer films

et al. 2016

View full text Add to dashboard Cite

In this paper two groups supporting different views on the mechanism of light induced polymer deformation argue about the respective underlying theoretical conceptions, in order to bring this interesting debate to the attention of the scientific community. The group of Prof. Nicolae Hurduc supports the model claiming that the cyclic isomerization of azobenzenes may cause an athermal transition of the glassy azobenzene containing polymer into a fluid state, the so-called photo-fluidization concept. This concept is quite convenient for an intuitive understanding of the deformation process as an anisotropic flow of the polymer material. The group of Prof. Svetlana Santer supports the re-orientational model where the mass-transport of the polymer material accomplished during polymer deformation is stated to be generated by the light-induced re-orientation of the azobenzene side chains and as a consequence of the polymer backbone that in turn results in local mechanical stress, which is enough to irreversibly deform an azobenzene containing material even in the glassy state. For the debate we chose three polymers differing in the glass transition temperature, 32 °C, 87 °C and 95 °C, representing extreme cases of flexible and rigid materials. Polymer film deformation occurring during irradiation with different interference patterns is recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the kinetics of film deformation. We also demonstrated the unique behaviour of azobenzene containing polymeric films to switch the topography in situ and reversibly by changing the irradiation conditions. We discuss the results of reversible deformation of three polymers induced by irradiation with intensity (IIP) and polarization (PIP) interference patterns, and the light of homogeneous intensity in terms of two approaches: the re-orientational and the photo-fluidization concepts. Both agree in that the formation of opto-mechanically induced stresses is a necessary prerequisite for the process of deformation. Using this argument, the deformation process can be characterized either as a flow or mass transport.

show abstract

Section: Reversible Switching Of the Polymer Film Topography During Changing Of Irradiation Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A comparative study of photoinduced deformation in azobenzene containing polymer films

et al. 2016

View full text Add to dashboard Cite

show abstract

“…31 In this case, polarized Raman spectroscopy can provide information about the symmetry of the vibration and hence can facilitate the assignment of spectral bands. Much work involving polarized Raman spectroscopy has been carried out in materials science on polymers, 30 nanowires, 32 and crystals. 33 34 wool and feather, 35 filamentous matters, [36][37][38][39][40][41] plant cell walls, 42 muscle, 43 bone, 44 and teeth.…”

Section: Theorymentioning

confidence: 99%

Polarized Raman Microspectroscopy Can Reveal Structural Changes of Peritumoral Dermis in Basal Cell Carcinoma

Piot²,

Durlach³

et al. 2008

Appl Spectrosc

View full text Add to dashboard Cite

Polarized Raman microspectroscopy can provide precious information regarding the orientation and ordering of the molecules in a sample without staining or particular preparation. This technique is used for the first time on a human skin section to probe the molecular modifications of the surrounding dermis in superficial basal cell carcinoma. Spectra using polarized and conventional Raman microspectroscopies were recorded on dermis bordering either the tumor or healthy epidermis. Band areas and spectral decomposition on selected vibrations were computed. Significant differences in dermal collagen vibration bands are detected using both polarized and conventional micro-spectroscopies, but the spectral changes between tumor and healthy tissues are enhanced using polarized Raman microspectroscopy. The analysis of these spectral differences highlights structural modifications of the triple helix of collagen. We see polarized Raman microspectroscopy as a potential tool that could be implemented for clinical analyses to guide clinicians and surgeons in the treatment of aggressive skin cancers. The information obtainable could also help better elucidate the molecular mechanisms induced in basal cell carcinoma development.

show abstract

“…Such polarization measurements are of particular interest in revealing the crystallographic nature of materials. [6,7] However, in nanoscience applications, this limited spatial resolution excludes the precise characterization of individual objects or domains that are much smaller than the diffraction limit. In this context, tip-enhanced Raman spectroscopy (TERS), which employs a metallic tip scanning the near-field of the probed object, presents significant advantages that can lead to a better spatial resolution.…”

Section: Introductionmentioning

confidence: 99%

Imaging of single GaN nanowires by tip‐enhanced Raman spectroscopy

Marquestaut

Talaga

Servant

et al. 2009

J Raman Spectroscopy

View full text Add to dashboard Cite

Raman imaging of a single [110]GaN nanowire using a combination of an atomic force microscope (AFM) and an inverted confocal microscope was investigated. The Raman spectra and associated maps of this single object, the diameter of which was of 200 nm, were collected in both confocal mode and with the interaction of an AFM tip to benefit from local tip enhancement effect. Beyond the pure tip-enhanced Raman scattering (TERS) effect, the setup was developed to integrate a commercial AFM and spectrometer to permit simultaneous topography and vibrational imaging with spatial and spectral resolutions determined by the respective instruments. Data exchange and communication of the Raman spectrometer and the AFM were optimized to display both height and Raman intensity for a set of Z positions at the AFM tip for each (x,y) position on the sample. The experiments were conducted with both a straight tip coated with gold at an excitation of λ = 647 nm and with a tilted tip coated with silver at an excitation wavelength of λ = 514 nm. The TERS signal was observed for a given phonon mode of the [110] nanowire, providing an optical resolution that corresponds to the size of the object.

show abstract

Polarized measurements in Raman microscopy

Cited by 13 publications

References 61 publications

A comparative study of photoinduced deformation in azobenzene containing polymer films

A comparative study of photoinduced deformation in azobenzene containing polymer films

Polarized Raman Microspectroscopy Can Reveal Structural Changes of Peritumoral Dermis in Basal Cell Carcinoma

Imaging of single GaN nanowires by tip‐enhanced Raman spectroscopy

Contact Info

Product

Resources

About