The Research Of Characteristics Of Periodically Poled Of KTP Crystal

This work is supported by national Nature Science Foundation. In this dissertation, quasi-phase-matched technology is researched in theoretical ways. The properties and analysis of periodically poling of KTP crystal are obtained through experimental research.The Quasi-Phase-Matched technology is a method in which fabricate a periodical structure on optical crystal to make it satisfy phase match condition in nonlinear frequency conversion. KTP crystal has a lots of outstanding properties of electro-optics, piezoelectricity, pyroelectricity and optical nonlinearity, especially it's coercive field is only a tenth of LiNbO3, so it has been used widely in the region of Quasi-Phase-Matched technology.The periodical polarization reversion of KTP crystal utilizing electric field suffers from it's high conductivity. Before polarization reversion, we reduced the conductivity of surface of KTP by Rb exchang method and the whole process of polarization reversion is monitored utilizing electro-optic effect. Major contributions are as follows:1,Based on Maxwell's equations, the couple mode equations between three light waves are educed and the formula of the efficiency of SHG is gained.2,The major concepts, such as spontaneous polarization, pyroelectric effect, piezoelectricity etc.,are described.3,The dielectric, optical and optic damage properties of KTP crystal are analyzed in this dissertation.4,The KTP crystal is periodically poled by electric field utilizing metal and liquid electrodes.5,The monitoring method utilizing electro-optic effects of KTP crystal is analyzed theoretically. The whole process of periodically reversion of KTP is monitored and the results are agreed with theoretical analysis.6,The confocal cavity and three-mirror folded cavity used in SHG are analysized and optimizing condition is discussed. Then the experiment of SHG of 1064nm fundamental light with PPKTP is carried out and we obtained 8mW green light under 710mW fundamental light and the efficiency of SHG in single-pass is 1.13%. There is no other similar achievement reported in China.