The Study Of Photorefractive Effect And Ferroelectric Domain Of Mn:Fe:KTN Crystal

Due to its excellent electro-optic effect and photorefractive effect,such as very large Kerr coefficient,high diffraction efficiency and fast electro-optic response time,potassium tantalite niobate(KTN)crystal has been widely applied in such fields like electro-holographic switching,holographic data storage,optical deflection and optical focus and so on.In this paper,the photorefractive effect and ferroelectric domain of the Mn:Fe:KTN crystal has been studied.The main work as follow has been done in this paper:1.The single center transport model and the double center transport model are investigated in theoretical,the refractive index change of Mn:KLTN and Mn:Fe:KTN crystal under different applied voltage,writing laser power,temperature and exposure time are analyzed.The electro-controlled light induced refractive index change of Mn:KLTN and Mn:Fe:KTN crystal by sheet light under different experiment conditions is measured by digital holographic interferometry in situ.The experimental results are in good agreement with the theory.2.Microscopy holographic interferometry system is involved,which can visualize the writing and erasing of the Bragg grating in situ.The refractive index change and the diffraction efficiency under different recording situations such as applied voltage,writing laser power,temperature,annealing rate and exposure time can be calculated as well and compared with theoretical results.The results of this research provide optimal writing parameters for the electro-controlled holographic optical switch.3.The method of holographic interferometry is used to make the photonic lattice into Mn:Fe:KTN crystal,and the periodic structure of the photonic lattice is visualized utilizing digital holographic microscopy.The theoretical analysis is carried out.4.The ferroelectric domain of crystal is observed by the polarization imaging technology.The phenomenon of the orientations of domain-wall,the thermoelectric effect,the self recovery,the version and the polarization of domain are also analyzed.The transmission light of the domain under different plorized light,applied voltage,temperature and annealing rate is given,and the preliminary analysis is carried out.The result of this research provides theoretical guidance for the growth and control of the domain.