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Computer simulation of modulated two-beam interference using monochromatic light

Hamed A.M.

Optica Applicata

2004

Vol. 34, nr 1

51-61

Two different models are suggested to describe the fringe shift obtained from the two beam interference modulated by the phase variations of transparent objects. The first model of the fringe shift assumes a linear triangular distribution, while the second model varies as a truncated Gauss function. The Abel transform enables computation of the refractive index distribution from the theoretical data of the fringe shift. The fringe shift of the phase object is represented in the harmonic term of the intensity distribution formula. A computer program is written to plot both of the fringe shifts of the models described and the corresponding refractive indices of the phase object. Comparative results are cited in the introduction which are based on an algebraic reconstruction technique (ART) using two models; one of them has a cosine phantom field which constructs an asymmetric single peak, while the other model has cosGauss function giving an asymmetric double-peak phantom. These results are compared with our results, which gives only a single peak in both cases of linear and quadratic variations, which is convenient for use in optical fibers.

Diffraction using an amplitude grating object of truncated inverted parabolic shape

Hamed A.M.

Optica Applicata

2002

Vol. 32, nr 4

833-841

A theoretical model of an inverted parabolic function is considered to represent an amplitude object. The intensity distribution of the diffraction pattern is calculated by applying Fourier transformations and convolution operations upon the object. A computer program is constructed to plot the intensity distribution of the diffraction pattern obtained. In the computations, the maximum heights of the inverted parabolic function are taken to be 2.5, 5, and 10 mm, while the object width is kept constant at 5 mm. The theoretical results of the intensity distribution are graphically represented using MATLAB program. Finally, a discussion and conclusions are presented.