Molecular optics laser examiner

An important development in Raman spectroscopy has been the coupling cf the spectrometer to an optical microscope. This allows the chemical and structural analysis described above to be applied to sample volumes only 1 across [38]. No more sample preparation is required than that for optical microscopy, and the microscope itself can be used to locate and record the area which is analyzed. This has obvious practical application to the characterization of small impurities or dispersed phases in polymer samples. This instrument, which may be called the micro-Raman spectrometer, the Raman microprobe or the Molecular Optics Laser Examiner [39] has also been applied to the study of mechanical properties in polymer fibers and composites. It can act as a non-invasive strain gauge with 1 fim resolution, and this type of work has recently been reviewed by Meier and Kip [40]. Even if the sample is large and homogeneous, there may be advantages in using the micro-Raman instrument. The microscope... 

In his Ph.D. thesis [61], Dhamelincourt detailed optical considerations for the design and implementation of a Raman microprobe and microscope, based on commercial optical microscopes, a design that was commercialized as the MOLE (Molecular Optical Laser Examiner) by Lirinord/Jobin Yvon. In this system, a beam splitter in a standard epi-illuminator (Fig. 3) was used to disentangle the incident laser beam from the Raman scattered beam. 

Molecular optical laser examiner (MOLE) Instrument eombining a laser excitation source with a microscope, resulting in a raman spectrum which can be used to fingerprint chemically small particles or thin films of complex compounds. 

The molecular structures of the surface vanadium oxide species on the different supports were examined with Raman spectroscopy. The Raman spectrometer system possessed a Spectra-Physics Ar+ laser (model 2020-05) tuned to the exciting line at 514.5 nm. The radiation intensity at the samples was varied from 10 to 70 mW. The scattered radiation was passed through a Spex Triplemate spectrometer (Model 1877) coupled to a Princeton Applied Research OMA III optical multichannel analyzer (Model 1463) with an intensified photo diode array cooled to 233 K. Slit widths ranged from 60 to 550 m. The overall resolution was better than 2 cm l. For the in situ Raman spectra of dehydrated samples, a pressed wafer was placed into a stationary sample holder that was installed in an in situ cell. Spectra were recorded in flowing oxygen at room temperature after the samples were dehydrated in flowing oxygen at 573 K. 

Laser-induced molecular dynamics we will examine below is driven by an oscillating electric field whose strength is comparable to the atomic Coulomb field. Solving for molecular dynamics in such strong optical field requires a non-perturbative approach. 

The remainder of this chapter is organized in four parts. ELECTRON SOLVATION TIMES IN POLAR LIQUIDS briefly summarizes the electron solvation data available from various laboratories by the NATO ASI 1987 conference date FEMTOSECOND LASER SPECTROSCOPY outlines the novel femtosecond laser spectroscopy techniques for studying ultrafast molecular motion EXPERIMENTAL RESULTS ON FEMTOSECOND KERR RESPONSES presents the femtosecond nonlinear optical data recently obtained by us for several simple organic liquids and, in concluding, examines how these ultrafast responses could be linked to future experiment and theory of electron localization and solvation. 

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