Polarized light linearly

In frequency regions where absorption is small the two indices of refraction , and n2 give rise to the phenomenon of double refraction. One of the most common uses for this property is in making wave retarders such as quarter-wave plates incident light linearly polarized with equal x and y field components is phase shifted upon transmission because of the two different phase velocities c/w, and c/n2. An entire field, usually referred to as crystal optics, arises out of this and further applications of crystal anisotropy. 

Fig. 2.4. Distribution Pb( ,

Figure 4. The MF PADs for single-photon ionization of ai and <22 symmetry orbitals of a model C3V molecule for light linearly polarized along different axes of the molecule (indicated in parentheses). Note that no photoionization can occur from the <22 orbital for light polarized along the z axis (molecular symmetry axis). The same dynamical parameters as for the calculations of the LF PADs shown in Fig. 3 were used. For further details see Ref. [55],...

In the following discussion, A and B refer to the trans and cis isomers, respectively. We assume that A- B photoconversion occurs upon excitation of a purely polarized transition with light linearly polarized along the laboratory axis Z, and we define a site-fixed, right-handed orthogonal system of axes for each of the isomers A and B in which the molecule can exist, such that the angle between the and Zb axes is x- In isomers A and B, the electric dipole moments and responsible for excitation of a photochemical... 

Figure 4.3 shows the photo-orientation, i.e., the dichroism, observed in the azo-silane SAMs. These spectra were obtained after 3 minutes of irradiation with linearly polarized UV light. It is clear that the absorption, Absx, recorded with the probe light linearly polarized perpendicular to the initial UV-light polarization, is higher than the absorption, Abs//, recorded with the probe light linearly polarized parallel to the initial UV-light polarization. Identical spectra were recorded for both Abs// and Absx prior to UV irradiation (only... 

For all the azo-polyglutamate LBK-polymer films, all the WGS experiments mentioned above were repeated by setting the UV and blue lights linearly polarized, in the plane of the sample, successively parallel and perpendicular to the dipping direction the same results were obtained for both UV and blue-light directions of polarization. In other words, no photoselection effect has been detected in these LBK structures. This is in contrast to the results obtained in a spin-cast film from the Pi.io polymer used in this study, and can be due to the subtle manner of the reorientation of the azobenzenes imposed by the LBK deposition technique, because efficient photoselection, following photoisomerization induced reorientation, can easily be achieved in spin-casted azo-polymer films [7-13]. This effect is discussed in the next section. 

We go back to the model discussed in 4.1.1, viz, a twisted stack of thin birefringent layers. The principal refractive indices of each are and n, and the angle of twist between the successive layers is p. Let r , t , r and t be the reffexion and transmission coefficients for a single layer for light linearly polarized along its principal axes at normal incidence. For polarization along the a axis. 

Fig. 7.5 Level scheme for optical pumping of Zeeman levels by light linearly polarized in the y-direction. Each of the two excited Zeeman levels can decay in three final-state sublevels. Superposition of the two different routes...

Curves are drawn for the cases of the incident light linearly polarized in the scattering plane, lu, and perpendicular to it, ly The dashed and solid curves represent the scattering dipole located at x = 0.01a, y = z = 0 and x=0.7a,y=z=0, respectively... 

In addition to measuring solid samples by the methods just described, the orientation of dyes in suspension has been investigated using electric dichroism (199-205). Electric linear dichroism (ELD) measures the change in the absorption of incident light linearly polarized parallel and perpendicular to the applied electric field direction, as schematically shown in Figure 19. This technique has been applied extensively for dye-polyelectrolyte solutions. For cationic dye-clay systems, the roll and tilt angles of dyes at the surface of clays have been derived by detailed analysis of the ELD. It should be noted that electric dichroism can be performed only in solution of low ionic conductivity. IntCTcalation compounds... 

Another solution is 8=( + 1,0,0) 0=0. This solution corresponds to a light linearly polarized along the molecular director. This solution is always stable. 

Incident light linearly polarized in the x-direction (a = 0°) becomes, after transmission through a A/4 polarizer with its slow axis in the x-direction... 

Because lights are transverse waves, only the transverse (2, 3 directions) deviations of the reflective index can cause the shift of the Bragg wavelength. Substituting Eqs. (10.4), (10.5) and (10.6) into Eq. (10.3), the peak wavelength shifts for the light linearly polarized in the second and third directions are given below ... 

Figure 4. Optical properties of a cholesteric liquid crystal (Type dextro incident light linearly polarized)...

Stokes vector, intensity of light linearly polarized at n degrees J = Bessel functions J = Jones matrix k = extinction coefficient m = dimensionality of z M = Mueller matrix, normalized Mueller-Jones matrix M vij = Mueller-Jones matrix n = refractive index Nq, N[, = complex refractive indices ... 

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