Generation Of Tunable Bessel Beams Based On Spatial Light Modulators

Recently,Study shows that bessel beams are widely used in the field of optical micromanipulation,laser processing,microscopy imaging and nonlinear optics by the nature of non-diffraction and self-healing of bessel beams.So Bessel beams(BBs)have been widely studied by domestic and overseas researchers.In this paper,we build a beam shaping set-up using Spatial light modulator(SLM)and proposed a new type of Bessel-like beams(BLBs)with central lobe size of the Bessel field calculated precisely theoretically along the propoagation distance.The main work includes the following aspects:(1)The beam characteristics of BBs,non-diffraction distance,cental lobe size,and the on-axis intensity,generated by axicon and linear axicon phase transform function are analyzed and calculated theoretically.What’s more,a numerical simulation method by using the angle spectrum method was deduced analysing the propagate characteristics of BBs.(2)A beam shaping and characterization set-up was built to generate BBs using SLM.Here we demonstrated the generation of different scaled BBs simulationly and experimently by loading different parameter in phase function,which turned out the reliability of the experimental system.Finally,Measured central main lobe width for the generated BBs ranges from1μm to 3μm.(3)We proposed two kinds of BLBs phase modulation functions whose size of the central lobe can be controled along the propoagation.The first type of BLBs(divergent and convergent modulation phase functions),the size of the central lobe of the phase varies linearly along the propoagation distance.The second type of BLBs(sinusoidal and cosine modulation phase functions),the central lobe size of the BLBs varies nonlinearly along the propoagation.The phase mask presented in this paper provides a simple and intuitive manipulation of the central lobe of the BLBs.The results may provide a powerful tool for many potentially demanding applications.