The effect of spot size on the fractal optical modulation

الملخص EN

The present paper analyze the signal emitting from the reticle during changing the spot size of laser falling on the disk and show the optimum frequency and the amount of energy window in different pattern of modulator (Reticle).

All results obtained by establish a special program named “Disk optical modulator version 3" using the language visual basic 6 contains many parameters.

All model of optical modulator consist of twenty sectors, ten sectors are opaque and other ten sectors are transmitted for the laser.

The number of sectors depends on several factors as chopping frequency, power transparent and modulation transfer function.

It has been demonstrated by simulations, the optimal value of modulation transfer function achieved when spot size of laser 0.3 mm and any increasing in spot size lead to decrease in MTF value.