Study On Axicon Cone Bessel Beam And Local Hollow Beam

Since the birth of axicon in 1954,the research on this optical element has never been interrupted.In more than half a century,researchers have successively obtained zero order Bessel beams,high order Bessel beams and local hollow beams through axicon mirrors.These new beams have gradually been widely recognized and applied in many fields because of their unique optical properties.For example,Bessel beam is used in laser processing,laser collimation and so on,while local hollow beam is used in micro super-resolution,optical capture and other fields.Although researchers have carried out in-depth research on axicon,there are still many aspects worthy of discussion,such as dark field microscopy and scanning holography.In this paper,the Bessel beam and the local hollow beam produced by the axicon are studied1?The limiting resolution of optical system is introduced.In this paper,several methods of super-resolution optical microscopy that break through the limit resolution are briefly summarized.At the same time,the imaging properties and characteristics of open field microscopy and dark field microscopy are also discussed,and the imaging differences between open field microscopy and dark field microscopy are compared.It can be seen that the resolution and contrast of dark field microscopy are improved compared with that of open field microscopy.2?This paper summarizes the principle of traditional optical tweezers,and analyzes the combination of optical tweezers system and dark field microscope system to improve the resolution.The parallel beam generates a local hollow beam through an axicon,which is transformed into a proper size through a lens.After entering the dark field condenser,it is compressed and converged to form a ring optical tweezers.The particles in the culture dish can be captured near the ring light.The scattered light of the captured particles provides us with the outline of the ring light and realizes the visualization of the ring light under the dark field microscopic imaging.By adjusting the distance between the observed particles and the dark field condenser,the size and intensity distribution of the ring light can be changed.When the size of the ring light is close to that of the single particle,the particle is stabilized at the maximum intensity gradient,and the contrast of the micro imaging is also improved,and the resolution reaches beyond the diffraction limit.3?In this paper,an improved scheme of efficient extraction of high frequency information in optical scanning holography(OSH)system is proposed.One pupil is replaced by the Laguerre Gaussian(LG)beam axicon.Compared with the result of edge extraction using ring pupil,this scheme improves the ability of anti noise and imaging quality,reduces noise interference,improves the effect of dark field illumination,is more conducive to the extraction and observation of useful information,and can also achieve the edge extraction in a specific direction.