Refractive index dispersion curve

This analytical approach is difficult to apply to individual pigments because physical data relating to refractive index, dispersion curves and the absorption curves in the solid state are not available. A colligative approach, based on the Kubelka-Munk analysis which characterises pigments by only two constants, an absorption and a scattering coefficient, has been applied with considerable success to the computation of the proportions of pigments in mixtures needed to match a given colour. Much of the book Colour physics for industry is devoted to this topic [37]. 

Room temperature coefficients of refractive index dispersion curves... 

Figure 9 Refractive index dispersion curves for j8-BaB204...

Figure 3 (a) refractive index dispersion curves before and after poling 1 in the dark under nitrogen purge open squares for the TE mode unpoled film, open circles for the TM mode unpoled film, filled squares for the TE mode poled film, filled circles for the TM mode unpoled film (b) refiactive index dispersion curves before and after poling 1 in air with exposure to a fluorescent desk lamp at 125°C. 

Figure 10 Schematic representation of the refractive index dispersion curves of side-chain polymers and main-chain polymers with two-dimensional charge-transfer...

Figure 3.10 presents a typical function An uj). It can be seen that the dispersion curve is a superposition of two curves. The relatively wide component curve describes the anomalous refractive-index dispersion within the limits of the Doppler profile. The maximum refractive-index variation due to linear absorption is reached when the field frequency is tuned off resonance by an amount approximately equal to the Doppler half-width ... 

The narrow curve of reversed sign is due to the refractive-index dispersion in the saturated absorption region. The maximum dispersion value here is reached at a frequency detuning equal to the half-width of the narrow saturated absorption resonance ... 

The effects of temperature on the color development of the porous film in chlorobenzene were shown in Table 6 [23]. The coloration was reversible thermochromism. The refractive index of the materials generally decreases as the temperature increases, and the temperature dependence of the liquid is greater than that of the solid. For example, the temperature dependence (A/id/°C) of PVA and chlorobenzene was found to be 3.0 x 10 and 4.5 x 10" at 589.3 nm. Consequently, it is interpreted that the wavelength of the crosspoint between the dispersion curves of PVA and chlorobenzene shifts from the long side to the short side with increasing tem-... 

Using the refractive index value of the pyrazine LB film, we calculated the mode dispersion curves of the TM fundamental and the TM second-harmonic waves in the waveguide device composed of a waveguiding pyrazine layer and a fused quartz substrate when Nd YAG laser is used as a fundamental light (Fig. 18). These curves show that the Cerenkov type phase matching is possible in the range of the thickness from 410 nm to 510 nm. 

Dispersion of the radiative rate constant by local variations of the refractive index at the solid/gas interface. This could explain the tailing of the decay curves even at very low loadings, with lifetime components that are two to three times as long as the intrinsic radiative lifetimes in solution/85 This could also explain the disappearance... 

This scheme of frequency tripling was successfully tested with fuchsin in hexafluorisopropanol (a solvent selected for its low index of refraction and relatively flat dispersion curve) to frequency-triple the output of a neodymium laser 67,68) With an input power of 10 MW/cm2 a third-harmonic output of 0.2 mW/cm2 was measured. This low value was mainly due to the relatively high absorption of fuchsin at 355 nm. An improvement of the efficiency by a factor of 80 was found with hexamethylindocarbocyanine iodide in hexafluorisopropanol because of the much lower absorption of this dye at 355 nm. Since the absorption minimum of this dye is at 383 nm, one could expect an additional efficiency increase by a factor of 70 for a fundamental laser wavelength of 1.15 / 69>. Other cyanine dyes have been used for frequency tripling a fundamental wavelength of 1.89 /mi 70>. 

Figure 6. The guided mode dispersion curves for a birefringent film and an optically isotropic substrate. Both the fundamental and harmonic curves are shown. The TE mode utilizes the ordinary refractive index and TM primarily the extraordinary index. Note the change in horizontal axis needed to plot both the fundamental and harmonic dispersion curves. Phase-matching of the TEq(co) to the TMo(2o>) is obtained at the intersection of the appropriate fundamental and harmonic curves.

Absorption is one consequence of a (vibrational) transition, the spectral behaviour of the refractive index reflects the same phenomenon. Within the spectral interval of an absorption band the refractive index follows a dispersion curve. Kramers-Kronig integral equations (for applications in optics see Caldwell and Eyring, 1971 Hopfe et al., 1981 ... 

A set of s-polarized spectra of a polymer slab obtained with different angles of incidence is shown in Fig. 6.4-10 the small dispersion-like features are centred at the oscillator frequencies and follow the shape of the refractive index. With closely neighboured or even overlapping resonances, the anomalies are difficult to resolve since a dispersion curve extends over a wider spectral interval than the related absorption band does. This impedes e.g. the compilation of band tables to be used for searching in conventional spectral libraries. By no means an automatic peak-locating routine designed for absorption bands in transmission spectra must be applied the bands would appear to be shifted. In order to convert reflectance spectra into absorption-proportional ones. 

This procedure has been used to determine droplet size in sprays. Oseillations in the curve relating x and D can be smoothed out by the use of an incident laser beam having a broad speetral bandwidth [83]. An accumulation of independent scattering intensities from multiple scatterers ean be used to measure the mean droplet size of a group [84]. This procedure has been applied to water sprays and the experimental data confirmed by phase Doppler anemometry [85]. The applicability of the polarization ratio technique is strongly influenced by the complex refractive index of the dispersed media and is limited to media having a relative refractive index below about 1.44 [86]. 

Dispersion Variation of the velocity of light (and hence its refractive index i in a material (such as a crystal) as a function of the wavelength of the light. As a result of dispersion (for example, by a prism), white light is split (dispersed) into its component colors. The velocity of light in a medium usually increases smoothly as the wavelength increases, but if the incident radiation is strongly absorbed the curve becomes discontinuous at that point (anomalous dispersion). 

Figure II. Resolved perpendicularly polarized 189 nm absorption band of a-helical poly-L-alanine (see Table 2A and Figure 2IB), left-hand ordinate, dashed curve. Plotted on the right-hand ordinate as the solid curve is the contribution to the refractive index of the single band, calculated using equation 19. Note that the dispersion curve is anomalous in an absorption region rather than monotonic, as is the water curve of Figure 12.

Figure 12. Solid curve the refractive index of water showing a simple, monotonic dispersion curve. Dotted curve the contribution of the 189 nm band of iV-methylacetamide at a 1 M concentration added on to the water curve using equation 19. The point to be made is that there is no way to match the background curve of a good solvent to the anomalous dispersion of a chromophoric system under study. Such matching is commonly attempted to remove light scattering problems which depend on the difference in refractive index of the particle, n, with that of the solvent, n, i.e., (tip—nf). The dashed curve adds the second dispersion term in equation 25. Also included is the calculated refractive index of particulate poly-L-glutamic acid (PGA) (see section 4(cKii))-...

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