اعلانات هامة

The knowledge of the angular spectrum of plane waves allows the accurate determination of a complex amplitude of the Gaussian beams during its propagation in free space between two planes: The first plane represented by the location of the beam waist; that is, when z=0 ; to the second parallel plane which is represented by different locations which propagate according to the z-axis in a homogeneous and isotropic material.                                                                    

One of the very effective methods of calculating the diffraction propagation of an arbitrary complex amplitude distribution – with its real and imaginary parts - is to decompose the distribution into a summation of plane waves, and to analyze all the components of these plane waves individually using the eigenvalues. This procedure is called “The Angular Spectrum Decomposition Method”.                                                          

This research aims to an analytical study and a numerical simulation of the physical properties of the variables of Gaussian beams propagation for the fundamental mode TEM00  in free space using the angular spectrum technique for both of the following lasers: He-Ne A=632.8nm and Argon A=514.4nm. The equations representing these variables are derived by using a pair of Fourier transformations via the angular spectrum propagation technique with spatial angular frequency variables.This study is represented by a special computational program written with Gaussian beams diffraction for laser modes. By this algorithmic writing, the study of many optical applications can be done. 

Keywords: Gaussian beam – Angular spectrum propagation –Fundamental mode  -Numerical simulation

إن معرفة الطيف الزاوي للأمواج المستوية تسمح لنا بدقة تحديد السعة العقدية للحزمة الغاوصية أثناء انتشارها في الفراغ الحر بين مستويين: الأول الممثل بموضع خصر الحزمة عند z=0  والثاني الموازية له والممثل بأبعاد مختلفة لقيم z المتصاعدة والتي تنتشر وفق المحور z في الأوساط المتجانسة والمتماثلة المناحي.