Refractive imaginary part

Figure Bl.26.13. Plot of versus K, the imaginary part of the refractive index.

Figure 7-13. (a) Linear absorption of DOO-PPV, (b) imaginary part of ) (proportional to two-photon absorption), and (c) real part ol (proportional to the nonlinear index of refraction. .). 

Imaginary part of complex principal refractive index Birefringence... 

Figure 11. Imaginary part of complex refractive index for polystyrene...

Ellipsometry is used to study film growth on electrode surfaces. It is possible to study films at the partial monolayer level and all the way up to coverage of thicknesses of thousands of angstroms while doing electrochemical measnrements. To get nseful data it is important to determine A and j/ for the bare electrode snrface and the surface with a film. These data are processed to derive the film thickness, d, and the refractive index, h, which consists of a real (n) and imaginary part (k), h = n- ik. So ellipsometry gives information on the thickness and refractive index of snrface hlms. 

From Eq. (3) derive the relations for the real and imaginary parts of the refractive index as Auctions of the permittivity and the electrical conductivity of a given medium. Note drat both n and k are defined as real quantities. 

The Z-scan technique, first introduced in 1989 [64, 65], is a sensitive single-beam technique to determine the nonlinear absorption and nonlinear refraction of materials independently from their fluorescence properties. The simplicity of separating the real and imaginary parts of the nonlinearity, corresponding to nonlinear refraction and absorption processes, makes the Z-scan the most widely used technique to measure these nonlinear properties however, it does not automatically differentiate the physical processes leading to the nonlinear responses. 

The real part of this nnmber is the normal refractive index n = c/v(c and v being the speed of light in vacnnm and in the medium, respectively). The imaginary part of the complex refractive index, k, is called the extinction coefficient. It is necessary to recall here that both magnitndes, n and k, are dependent on the frequency (wavelength) of the propagating wave co,N = N(co). 

The real and imaginary parts of the complex refractive index satisfy Kramers-Kronig relations sometimes this can be used to assess the reliability of measured optical constants. N(oj) satisfies the same crossing condition as X(w) N (u) = N( — u). However, it does not vanish in the limit of indefinitely large frequency lim JV(co) = 1. But this is a small hurdle, which can be surmounted readily enough by minor fiddling with JV(co) the quantity jV(co) — 1 has the desired asymptotic behavior. If we now assume that 7V( ) is analytic in the top half of the complex [Pg.28]

The rate at which electromagnetic energy is removed from the wave as it propagates through the medium is determined by the imaginary part of the complex refractive index. If the irradiances I0 and lt (or rather their ratio) are measured at two different positions z = 0 and z = h, then a, and hence k, can be obtained in principle from the relation... 

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