Light unpolarized

Note that this also involves the assumption of isotropic molecules, which have the same polarizability in all directions. Unpolarized light consists of equal amounts of vertical and horizontal polarization, so the fraction of light scattered in the unpolarized (subscript u) case is given by... 

Figure 10.6 Two-dimensional representation of i and i (broken lines) and their resultant ifotai (solid line) for scattering by a molecule situated at the origin and illuminated by unpolarized light along the x axis. The intensity in any direction is proportional to the length of the radius vector at that angle. (Reprinted from Ref, 2, p. 168.)...

The electric field of plane-polarized light oscillates in a single plane. It can be prepared hy passing ordinary, unpolarized light through a polarizer, which consists of a material that allows the light to pass only if the electric field is aligned in a certain direction. 

In general, when using unpolarized light, the vibrations both parallel and perpendicular to the interface are excited. However, when the light is polarized, selected dynamic dipoles are excited, from which the orientation of the dipoles can be inferred. 

If the foregoing created the impression that the electric and magnetic vectors of a propagating electromagnetic field are confined to vibrate in fixed planes, that was unintentional. A field like that would be plane polarized and to create that requires a special device known as a polarizer. Ordinary unpolarized light consists of an array of plane waves that are randomly oriented with respect to a plane perpendicular to the directions of propagation. 

The polymer-substrate (2-3) interface is assumed to be sharp and smooth, but the plasma-polymer (1-2) interface may be diffuse or rough. Unpolarized light of vacuum wavelength A is incident upon the system from region 1 at an angle 0, relative to the normal. 

For unpolarized light, this relation is a very good approximation for incidence angles d., < 15°. When f < 1, the observed ratio is x - (R-/R+) "4 < x°. If r12 were small, then the fact that f would compress the waveform symmetrically about the value R could be used to find x°, and hence Note that this analysis would also... 

Figures 19.1 (a) and (b) depict the ordinary or unpolarized light and plane-polarized light respectively.

Figure 1.10. Fluorescence microscopy pictures of two 1500-nm long zeolite L crystals containing DSC. Excitation with unpolarized light at 480 nm. Left Unpolarized observation. Middle and right Linearly polarized observation. The arrows indicate the polarization direction. (See insert for color representation.)...

For unpolarized light the irradiance ratio is the average of the ratios for parallel and perpendicular polarization... 

Thus, if unpolarized light or, indeed, light of arbitrary polarization is incident on the optical system described by the Mueller matrix (2.92), the transmitted light will be 100% right-circularly polarized. Note that matrix multiplication is not commutative the order of elements in a train must be properly taken into account. Further details about Mueller matrices and experimental means for realizing polarizers, retarders, and other optical elements are found in the excellent book by Shurcliff (1962). 

If unpolarized light of irradiance /, is incident on one or more particles, the Stokes parameters of the scattered light are... 

Equation (5.6) applies to incident unpolarized light it is important to remember that the angular distribution of the scattered light depends on the polarization of the incident light ... 

Figure 5.2 Degree of polarization of light scattered by a sphere small compared with the wavelength for incident unpolarized light.

Figure 8.10 Phase function for scattering of unpolarized light by an infinite cylinder. The arrows indicate minima according to diffraction theory.

Extinction is easy to measure in principle but may be difficult in practice, especially for large particles where it becomes difficult to discriminate between incident and forward-scattered light. Spheres and ensembles of randomly oriented particles do not linearly polarize unpolarized light upon transmission. But single elongated particles or oriented ensembles of such particles can polarize unpolarized light by differential extinction. 

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