The absorption index, k, introduces an exponential decay in E (and E ) with increasing z (see eq. [3]). Recalling that the intensity, I, is related to the electric field amplitude E, according to I lE 2 it follows from eqs. [3] and [4] that [Pg.76]

With increasing absorption index k, the absorption of very small particles increases. [Pg.26]

Table 23 Refractive index, n, and absorption index, k, of the ordinary ray for sapphire in the ultra-violet spectral range, at 25°C, from [49, 50] |

Figure 6.4-14 Spectra of the refractive index n, the absorption index k, and the degree of (phase) polarization Ppi, of quartz glass as derived from ellipsometric measurements. |

The top curve in Figure 8 applies to pigments with a high absorption index k and low refractive index rt (e.g., carbon black) and shows that the optimal particle size lies below a given limit. [Pg.26]

In contrast with other methods, spectra recorded by specular reflection show dispersion-like shaped bands because both the refractive index (n) and the absorption index (k) contribute to reflection. These can nevertheless be separated [Pg.311]

Mie applied the Maxwell equations to a model in which a plane wave front meets an optically isotropic sphere with refractive index n and absorption index k [1.33-1.36]. Integration gives the values of the absorption cross section and the scattering cross section Q these dimensionless numbers relate the proportion of absorption [Pg.28]

In Mie s theory, the scattering diameter Qg and the absorption diameter are related to the particle size D, the wavelength A, and the optical constants of the material (refractive index n and absorption index k). [Pg.22]

Figure 6.4-5 Simulated spectra of a strong oscillator (strength/ = 200 10 cm with resonance at t> real and imaginary part of the dielectric function = s + k", refractive index n and absorption index k, ellipsometric parameters A and ip, as well as reflectance R for the angles of incidence and the polarization states stated. |

Fig. 57. Harmotome. IR reflection spectra (a) reflectivity, (b) imaginary part of the dielectric function e , (c) real part of the dielectric function e , (d) imaginary part of the refractive index k (absorption index), (e) real part of the refractive index n [88S3], |

The considerations before refer to the non-absorbing case when and n are real quantities. In order to characterize the optical properties completely absorption must be included. This can be achieved by taking the optica] and dielectric functions to be complex quantities comprising two real figures each. The (real) refractive index n is complemented by the real absorption index k to constitute the complex refractive index [Pg.576]

Fourier transform infrared microscopes are equipped with a reflection capability that can be used under these circumstances. External reflection spectroscopy (ERS) requires a flat, reflective surface, and the results are sensitive to the polarization of the incident beam as well as the angle of incidence. Additionally, the orientations of the electric dipoles in the films are important to the selection rules and the intensities of the reflected beam. In reflectance measurements, the spectra are a function of the dispersion in the refractive index and the spectra obtained are completely different from that obtained through a transmission measurement that is strongly influenced by the absorption index, k. However, a complex refractive index, n + ik can be determined through a well-known mathematical route, namely, the Kramers-Kronig analysis. [Pg.118]

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