Incident laser beam

A diffuser G is illuminated with a He-Ne laser, trough a rectangular aperture A, which limits the illuminated area. A graduated screen is located at the observation plane 110(71, ), located at a distance D from the reference plane n(x,y), and perpendicularly arranged to the incident laser beam. The rotation axis y is also perpendicular to the beam. 

LIF Laser-induced fluorescence Incident laser beam excites Excited-state processes ... 

Several practical issues of the scatterometer must be considered in the case of characterizing nominally smooth surfaces. The incident laser beam may be collimated, but more commonly it is brought to a focus at a distance defined by the arc in which the detector rotates. In addition, a deflection mirror or an optical fiber might be used to direct light to the detector element. These features permit measurements close to the specular and transmitted beams, and this is critical to folly characterize the scattered light. This is especially significant since the scattered light intensity... 

Above a pump energy of 20 pJ for the incident laser beam a strong spectral narrowing of the PL-spcclra of m-LPPP could be detected. The recorded spectra... 

Phosphoric acid ester was used as a model for the estimation of concentration of a reagent in an adsorbed layer by optical measurements of the intensity of a beam reflecting externally from the liquid-liquid interface. The refractive index of an adsorbed layer between water and organic solution phases was measured through an external reflection method with a polarized incident laser beam to estimate the concentration of a surfactant at the interface. Variation of the interfacial concentration with the bulk concentration estimated on phosphoric acid ester in heptane and water system from the optical method agreed with the results determined from the interfacial tension measurements... 

In Raman measurements [57], the 514-nm line of an Ar+ laser, the 325-nm line of a He-Cd laser, and the 244-nm line of an intracavity frequency-doubled Ar+ laser were employed. The incident laser beam was directed onto the sample surface under the back-scattering geometry, and the samples were kept at room temperature. In the 514-nm excitation, the scattered light was collected and dispersed in a SPEX 1403 double monochromator and detected with a photomultiplier. The laser output power was 300 mW. In the 325- and 244-nm excitations, the scattered light was collected with fused silica optics and was analyzed with a UV-enhanced CCD camera, using a Renishaw micro-Raman system 1000 spectrometer modified for use at 325 and 244 nm, respectively. A laser output of 10 mW was used, which resulted in an incident power at the sample of approximately 1.5 mW. The spectral resolution was approximately 2 cm k That no photoalteration of the samples occurred during the UV laser irradiation was ensured by confirming that the visible Raman spectra were unaltered after the UV Raman measurements. 

The SERS spectra can be obtained on a conventional Raman spectrometer (see Figure 2). In this particular system, 632.8 nm radiation from a Helium-Neon laser is used with an excitation power of 5 mW. Signal collection is performed at 0° with respect to the incident laser beam. This coaxial excitation/collection geometry is achieved with a small prism, which is used to direct the excitation beam to the sample while allowing... 

Fig. 5.1. Direct visualization of filamentation in a 7.5 cm long crystal of BaF2. The incident laser beam enters from the right side...

Fig. 5.8. Spectrum of white light obtained upon irradiation of BaF2. Note the extent and flatness in comparison with the corresponding spectrum measured for the incident laser beam...

SHG can be extended to a true spectroscopy by varying the frequency of the incident laser beam. Electronic structures such as surface states and surface plasmon resonances show up in the frequency dependence of the signal [14]. 

A PMT mounted at right angles to the incident laser beam permits continuous recording of the light scattered at that angle. In addition, a 512-element linear photodiode array (not shown) is mounted on the ring electrode... 

An absolute value of M for each of these branched PVAcs was obtained from light-scattering measurements. In each case five polymer solutions were made up in tetrahydrofuran (THF) solvent and a Chromatix KMX-6 LALLSP instrument was employed to measure the intensity of light scattered from these solutions at 7° to the incident laser beam. A Chromatix KMX-16 laser differential refractometer was used to determine the refractive index increments, dn/dc, of the polymer solutions under ambient conditions. 

FIGURE 6.9a An experimental arrangement for observing the real-time flow of microscopic particle through the focal volume of the incident laser beam. 

Figure 7.11 shows the evolution of Raman spectra by increasing the light intensity of illumination. It is important to point out the existence of a certain threshold intensity of the incident laser beam—below 7th, the initial shape of the spectrum was recovered after turning off the illumination above it, the spectrum further transforms... 

Figure 17. Reflectivity (O) and Raman scattering intensities (9) for an Al-AlOx-4-pyridine-COOH-Ag tunneling junction prepared on a diffraction grating substrate, as a function of the angle between the incident laser beam and the normal to the grating surface (45). At the same angles that absorption by surface plasmons causes reflectivity dips, the Raman signal shows peaks.

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