In the case of a volume hologram (or Bragg hologram), the Bragg condition occurs and hence
Bragg diffraction in the formation of the image, as the optical path difference between wavefronts reflected from successive layers of material (photopolymer in this case) is an integral multiple of the wavelength.
The XRD analysis of this silica xerogel was performed by using Scherer equation in the form, D = kl/Bcosth, where the shape factor k is equal to 0.89, th is the
Bragg diffraction angle, l is the wavelength of X-rays having value equal to 1.5418 A and B is the full width of the observed peak at half maximum (FWHM).
The [d.sub.100] lattice constant of the (100)-oriented AlN thin films was calculated and it was about 0.27 nm using the following
Bragg diffraction equation:
Bragg diffraction occurs for an electromagnetic radiation when wavelength is of the same order of magnitude of the atomic spacing, if incident upon a crystalline material.
In the case of
Bragg diffraction (y0 > 0, yh <0) in the range
"This gives rise to entirely new optical properties due to
Bragg diffraction from the lattice planes of the opal.
XRD technique was used to ascertain a wide variety of structural information including; crystal interatomic spacing,
Bragg diffraction angle, and crystallite size of the deposited films.
More specifically, chapters discuss polarized light, electromagnetic waves in anisotropic materials, description of light propagation with rays, stratified birefringent media, space-grid time-domain techniques, organic optical materials, practical polarization optics with the microscope, optics of liquid crystal textures, refractive birefringent optics, diffractive optics with anisotropic materials, and
Bragg diffraction.
It can be clearly seen that the curves of M-PPS, HTM-PPS, and 12hM-HTM-PPS are identical to each other, showing all crystalline
Bragg diffraction. However, FHTM-12hM-PPS shows the characteristic of no crystalline
Bragg diffraction and has only a broad amorphous diffraction.
The arrays are brightly colored and act as diffraction gratings for white light according to the
Bragg diffraction equation (4,5):
The calculated function describes the scattered background and the position, shape and intensities of the
Bragg diffraction peaks.