Holographic method

The holographic method is a relatively new imaging technique developed about three decades ago. Since then, this method has been used in the study of airborne and liquid-borne particulate systems in their real world environments [21]. In a holographic experiment, images are formed in a two-step process. In the first step, a collimated coherent light is used to illuminate the sample. A hologram is formed by the far-field diffraction patterns of all the particles in the 

Since a hologram is recorded using a pulsed laser of a very short duration and since the particles are recorded in their real environment (suspension, aerosol, etc.), this method effectively records the sample at one particular moment. A more detailed study can be performed in the second step at some later time. This 

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This work presents the theoretieal results and their experimental verifications concerning two possible methods for predicting the material discontinuities shape and severity. The methods are developed for the case of the eddy current transducer with orthogonal coils, for two situations for long crack-tjfpe discontinuities, a metod based on the geometrical diffraction has been used, while in the ease of short discontinuities the holographic method is prefered. 

Since ED by a surface is a complicated process, there is no routine method available to directly and accurately extract atomic positions from the experimental data. Direct holographic methods have been proposed [24], but have not yet... 

D. Gabor (Imperial College, London) invention and development of the holographic method. 

Experimental applications include the direct deposition of patterns as small as 0.5 im in semiconductor applications using holographic methods, and the production of rods and coreless boron and silicon carbide fibers (see Ch. 19). 

A holographic method is basically a two-step imaging process that captures in permanent form the sizes and locations of... 

It is also feasible to measure both droplet size and velocity simultaneously with the holographic method. Such a measurement system has been developed by Murakami and Ishikawa. 65()l They used two pulse lasers of different wavelengths to record two holograms on two different films, separated by an appropriate time interval. The displacements of moving particles were measured on a superimposed picture of the two films to determine the velocities of the particles. 

Unfortunately, the experimental data cannot be correlated directly with the crystal structure, because some of the information needed is lost in recording the X-ray intensity pattern. Indeed, the diffracted X-ray beam is a vector, and it has both an intensity and a phase angle. The information concerning phase angle is lost during measurement of the X-ray intensity. The phase angle could, perhaps, be recorded by a holographic method, but X-ray lasers do not as yet exist. 

A holographic method has been used to investigate the cis-trans isomerization which occurs in the dye methyl red dissolved in poly(methyl methacrylate) and polystyrene SO Back isomerization... 

Combination with Spectroscopy, CBED and Holographic Methods... 

Fig. 30. Results of orthogonal circular polarization holographic optical data storage on BR-D96N film by Fourier transformation holographic method, (a) stored file (b) encoded binary monochromic image (c) retrieval diffractive image (d) decoded result (e) retrieved file (1) measurement of size of hologram (one grid of the scale corresponds to lOjim).

Meltz G, Morey W W and Glenn W H, Forming of Bragg grating in optical fibres by a transverse holographic method . Opt. Lett., 1989, 14, 823-5. 

McCarvill and Bell ° have described the use of torsional test for the determination of adhesive joint strength, and dynamic loss has been used to measure tire cord adhesion to rubber. Holographic method has been suggested as one non-destructive method for... 

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