Study On Propagation Properties Of Hollow Gaussian Light Beam

Hollow beam as a new type of beam is discovered in recent years. Its center intensity is zero. Due to the hollow beam with a novel and unique physical properties: for example, the barrel intensity distribution, the smaller dark spot size and propagation of invariance and with spin and orbital angular momentum and so on. Therefore, this unique light beam has a wide range of application prospects in the laser beam optics, binary optics, computer-generated hologram, micro-particle optical confinement, biological medicine. This paper mainly studies the propagation characteristics of hollow Gaussian beams. This work has important scientific significance. This major work and the results achieved are as follows:Firstly, the paper first introduces the definition of the hollow beam and background, and gives the method for producing the hollow beam in detail. Summary and analysis of a variety of evaluation criteria of laser beam quality, the common research methods in laser propagation and compare their advantages and disadvantages.Secondly, based on the theory of M2 factor of A.E.Siegman and the theory of general M2 factor of R.Martinez-Herro and others, We have studied the generalized propagation factor of the non-truncated and truncated hollow Gaussian beams in the rectangular coordinate system and cylindrical coordinates. The results show that the generalized beam propagation factor of the non-truncated hollow Gaussian beams only depend on the order of the number of n in the rectangular coordinate system cylindrical coordinate system, and the M2 factor increases along with the order of the hollow beam increases. When n=0, M2=1, here the hollow Gaussian corresponds to ideal Gaussian beam. The beam propagation factor of the truncated hollow beams in the rectangular coordinate system and cylindrical coordinate system riot only related to their order of n, but with the hollow beam truncation parameter. The results show that the M2 factor of hollow Gaussian beam decreases along with truncation parameterβincreases, when truncation parameterβbecome the larger, the M2 factor finally is to be stabilized.Thirdly, the propagation properties of hollow Gaussian beams through a paraxial ABCD optical system are studied by use of Collins formula, the corresponding analytical propagation expressions have been derived. By numerical calculation, the focusing properties of the hollow beam have been discussed in detail. On this basis, The propagation properties of hollow Gaussian beams passing through a lens series have been studied by use of non-apertured analytical propagation expressions.