Study On The Theory And Experiment Of Optical Programmable Electronically Controlled Beam Deflection

Optical beam deflectors have broad application prospects in the fields of 3D printing,3D imaging,high-speed bio-imaging.Due to the characteristics of fast response,arbitrary deflection angle,small volume,no movable parts and high reliability,the optical deflection technology based on electro-optic effect is considered to be most suitable for achieving high-speed beam deflection,which is one of the main directions of the future development of optical deflection technology and has great application prospects.In this dissertation,based on Mn doped potassium lithium tantalate niobate(Mn:KLTN)crystal at its paraelectric phase,the high-speed optical programmable electronically controlled beam deflection technology is studied theoretically and experimentally,"equivalent prism"based and Airy channel based two electronically controlled beam deflection technology are proposed.Main work is as follows:1.The physical mechanism of field-induced dark decay lifetime enhancement of photorefractive grating is studied,and a potential well model is proposed which explains this physical mechanism well.The external field re-orients and strengthens the polar nanoregions(PNR_S)in the crystal,forming a potential well that limits carrier migration,thus prolonging the dark decay time.The relationship between the dark decay time and the external field is given.This research will have important application value in photorefractive storage,holographic optical elements and so on.2.An induced beam with a linear gradient distribution of light intensity is designed and written into Mn:KLTN crystal,which induces a refractive index change with gradient distribution.This effect is equivalent to a prism.Digital holographic interferometry is involved,which can visualize the writing dynamic process of this induced beam in situ.The curves of the"equivalent prism"based beam deflection angle with the applied electric field and induced light gradient are given.The experimental results are in good agreement with the theoretical analysis.On this basis,the array induced beam is designed,and multi angle and multi direction array electronically controlled deflection is achieved,which provides a way for the array deflector.3.Based on split-step Fourier transform method,the propagation processes of the Gaussian beam in and out of the Airy channel are simulated.Airy induced beam is generated by computer-generated holography,and its characteristics and influencing factors are analyzed.The writing and probing optical systems of Airy channel is designed and set up,the temporal and spatial evolution of the writing of Airy channel is visualized in situ by digital holographic interferometry,which provides its phase change distribution.The characteristics of the Airy channel based electronically controlled beam deflection are measured.The experimental results are consistent with the theoretical analysis,which verifies the effectiveness of this method.