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对紫外激光诱导近化学计量比钽酸锂晶体铁电畴反转进行了实验研究。波长为351 nm的连续紫外激光被聚焦在近化学计量比钽酸锂晶体的-z表面,同时沿与晶体自发极化相反的方向施加均匀外电场。实验证实紫外激光辐照可以有效地降低晶体畴反转所需的矫顽电场,采用数字全息干涉测量技术检测证实在激光辐照区域实现局域畴反转。研究表明采用紫外激光诱导可以实现对近化学计量比钽酸锂晶体铁电畴反转的局域控制。提出了物理机理的理论分析,认为外电场和激光辐照场的共同作用在晶体内部产生高浓度、大尺寸的缺陷结构,缺陷一定程度上降低畴体成核和畴壁运动所需要克服的退极化能和畴壁能,实现激光诱导畴反转。
The UV laser-induced nearly stoichiometric lithium tantalate crystal ferroelectric domain inversion experiments were carried out. A continuous UV laser with a wavelength of 351 nm is focused on the -z surface of a near-stoichiometric lithium tantalate crystal while a uniform external electric field is applied in the opposite direction of the spontaneous polarization of the crystal. Experiments show that ultraviolet laser irradiation can effectively reduce the coercive field required for crystal domain inversion. The detection of digital domain holographic interferometry confirms the local domain inversion in the laser irradiation area. The results show that the local control of near-stoichiometric reversal of ferroelectric domains in lithium tantalate crystals can be achieved by UV laser-induced. The theoretical analysis of the physical mechanism is proposed. It is considered that the combined action of the external electric field and the laser irradiation field produces a high-concentration and large-size defect structure inside the crystal. The defects reduce the nucleation and domain wall movement to some extent, Polarization energy and domain wall energy, to achieve laser-induced domain inversion.