The singularity is located nearer to the central axis for the pulses with higher order transverse modes and shorter pulse duration.

In the purpose of using non-diffracting beams to extending the depth-of-field of optical imaging system, the variation rules of the central spot of non-diffracting beams are investigated.

The results show that lightcraft's attitude stabilization is achieved by gyroscopic effect, and that due to the side force and the aerodynamic damp, lightcraft has the ability to ride a laser beam.