Refractive index dispersion

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... 

From the air/liquid interface, the SHG signal is typically observed in reflection, where the coherent harmonic beam propagates along the same direction as the reflected fundamental beam. The possibility of significant refractive index dispersion in the liquid means that for SHG experiments on the liquid/liquid interface, the harmonic beam path may deviate from the reflected fundamental. 

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

After several tests, it is possible to estimate approximately the optimal relative intensities needed to obtain large photoinduced nonlinearities within relatively short preparation periods. The dependence of the generated SH signal is a function of the phase difference AO between the writing beams at CD and 2co frequencies. The relative phase difference AO can be varied by tilting a BK7 plate of known thickness and refractive index dispersion. ... 

At the top of Figure 6.15, the refractive index dispersion associated with an optical transition at a frequency greater than 2o) is schematically illustrated. The diflFerence in refractive index A q produces a phase diflFerence A< ) after the waves have traversed a distance L. Phase-matched versus non-... 

Figure 6.15. Refractive index dispersion and harmonic conversion efficiency versus interaction kngthfor various degrees of phase mismatch Ak.

Optical properties Refractive index Dispersion Reflection Refraction Absorption Transmission Color... 

The measured refractive index dispersions for benzylic amide [2] catenane, fumrot and norot are displayed in Figs. 15-17, respectively. In all cases we observe a birefringence due to the order created during the thin film deposition and favored by... 

Figure 15. Refractive index dispersion in a vacuum evaporated thin film of benzylic amide [2] catenane...

Figure 18. Refractive index dispersion in evaporated thin films of pure (triangles), monosubstitued (circles) and disubstitued fumrot (squares) (cf. Fig. 10). Full figures show ordinary whereas the open the extraordinary index of refraction, respectively. Solid lines are Sellmeier fits...

For most materials the reflected energy is only 5-10%, but in regions of strong absorptions the reflected intensity is greater. The data obtained appear different from normal tra(nsmission spectra, as derivative-iike bands result from the superposition of the normal extinction coefficient spectrum with the refractive index dispersion (based upon the Fresnel relationships from physics). However, the reflectance spectrum can be corrected by using the Kramers-Kronig (K-K) transformation. The corrected spectrum appears similar to the familiar transmission spectrum. 

Fig. 13. Refractive index dispersion for AlFj-doped ZrF4-BaF2-GdF3 glasses (A) 2 mol% AIF3 and (B) 6 mol% AIF3. (Mitachi and Miyashita 1983).

The Abbe number (vd) measures the extent of wavelength dispersion of the refractive index. Polymers possessing a high Abbe number, such as PMMA, show low refractive index dispersion and are useful for lens and other optical elements. As shown in Table IV, the Abbe number of the zero-birefringence polymers (poly(MMA-co-BzMA), PMMA-Stilbene, and PMMA-Tolan) having phenyl groups were lower than that of PMMA. The Abbe number of a polymer is represented as. 

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. 

Although this condition can be troublesome to set up experimentally, it does have the advantage that all of the signal can be easily collected. But for gas-phase studies where the refractive index dispersion is small, collinear beams can usually be used. 

S. T. Wu, A semiempirical model for liquid-crystal refractive index dispersions, J. Appl. Phys. 69, 2080 (1991). 

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