Research On Generation Of Airy Beams And Propagation Controlled By Using Spatial Light Modulator

In recent years, Airy beams have attracted wide interest due to its unique properties oftransverse self-accelerating, diffraction-free and self-healing properties in propagation.Depending on the spatial light modulator and computer phase holographic technology,the study of Airy beam on trajectory control, array generation and the experimentalsimulation of transmission in turbulence environments are proposed in this thesis.As a research foundation of the thesis, the theories of infinite energy Airy beams andfinite energy Airy beams are introduced. The method of generating Airy beams in linearspace is introduced. Firstly, the phase modulation characteristics of liquid crystal spatiallight modulator are measured for producing accureate cubic phase and ensuring theaccurate phase modulation in the subsequent experiments. Then, the transverseself-accelerating, diffraction and self-healing properties of Airy beams in propagationare demonstrated.To achieve arbitrary scanning of Airy beams in a larger angle range, anon-mechanical control method is proposed. By adding a controlled deflection gratingto the Airy cubic phase mask, a combined phase mask is generated. Simply adjustingthe parameters of deflection grating, the arbitrary scanning of Airy beams can beachieved. The demonstrations of this method have studied theoretically andexperimentally. To overcoming the shortcomings of the diffraction efficiency decreasesrapidly when the angle of deflection increases about conventional deflection grating, anoptimization phase deflection grating is proposed initially. The periodic distribution ofphase grating structure is selected. Through optimized addressing of the desired phasein the phase space of spatial light modulator, the deflection accuracy is improved, andhigh diffraction efficiencies at different angles are obtained.To solve the limitation of single beam which was used in the most study, a method ofusing the spatial light modulator to generate Airy beams array is proposed. TheDammann grating or optimized splitting grating is introduced into the design of phasemask. Superimposing the splitting phase grating and the Airy cubic phase pattern, thecombined functions of the two kinds grating are obtained. Employing this method, anarray of4×4spacing Airy beams are generated. A non-mechanical steering of Airybeams array is achieved by superimposing the combined phase mask with a controlleddeflection grating.In view of the transverse acceleration and self-healing properties of Airy beams, thereis a unique application in long distance propagation. However, there are a few reportson the Airy beams propagation in turbulence. So, the scintillation and spreadingbehavior are introduced briefly. The disturbing phenomenon of Airy beams and Circular Airy beam in weak turbulence is shown by numerical simulation. The transmission ofAiry beams in atmospheric turbulence is simulated experimentally by using a spatiallight modulator. The drift behavior of Airy beams and Circular Airy beams indisturbance is preliminarily studied, and are compared with the related Gaussian beam.Meanwhile, the effects of attenuation coefficient and phase modulation depth on thedrift of Airy beams in weak turbulent are discussed further.