Generating method of non-diffracting beam with long-distance propagation and controllable parameters

In order to eliminate the restriction of optical device geometrical parameters on the propagation characteristics of non-diffracting beams and to achieve the controllability of the characteristic parameters of non-diffracting beams propagating in long-distance space, the generation method of parameter controlled non diffracting beam over long distance is studied in this paper. First of all, by studying the electric field distribution of the axicon refraction shadow area, it is found that although the paraxial area beyond the critical surface of the axicon non-diffractive area is in the paraxial area of the geometric refraction shadow, there is still a spherical wave whose intensity follows first kind of zero-order Bessel function distribution. On this basis, a non-diffracting light generation method is proposed which is not limited by the distance of the propagation space. Finally 7 the parameters of the non-diffracing light propagation characteristics are tested in the range of nearly 12 m, and it is found that the difference between the experimental and theoretical values is less than 0.1 mu m. The non-diffracting beam is generated by collimating spherical diffracted light spots of the first kind of zero-order Bessel function distribution, which is essentially different from the traditional method of generating interference and non-diffracting light beams and is easy to generate large-scale space non-diffracting beams. In general, this method is particularly suitable for the use in non-energy conditions, such as largescale linear reference space, beam space communications, and has enormous engineering application value.