固体真实能带结构对超快电致吸收的影响研究

项目名称： 固体真实能带结构对超快电致吸收的影响研究

项目编号： No.61505023

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无线电电子学、电信技术

项目作者： 邓洪祥

作者单位： 电子科技大学

项目金额： 20万元

中文摘要： 超快电致吸收是指用超短脉冲激光(通常称为泵浦光)调制固体材料（半导体材料和绝缘材料）对探测光的吸收和透射。可用来研究固体材料在强激光辐照过程中的瞬态光学性质，有效能带，载流子的动力学行为等。根据强激光与固体材料相互作用的一般分类，可将泵浦光与固体的作用强度由弱到强分为多光子区，动态区及光学隧穿区。对于多光子区域和动态区域，由于激光强度不高，参与带间跃迁的主要是位于布里渊中心区域的电子，固体真实能带结构并不重要，可以用抛物型能带替代真实的能带。但当光强很强进入隧穿区域后，近几年的研究都显示这种近似已不适用，此时整个布里渊区域的电子都将起作用。因此在光学隧穿区域必须要考虑固体的真实能带结构。目前对超快电致吸收的研究都是采用抛物型能带近似，因此其无法适用于光学隧穿区域。通过研究固体真实能带结构对超快电致吸收影响，我们可以将超快电致吸收的研究从原先的多光子区域和动态区域扩展到光学隧穿区域。

中文关键词： 超快电致吸收；飞秒激光；固体能带结构；高功率激光；；激光诱导损伤

英文摘要： ultrafast electro-absorption is a setup that the transmission and absorption of detective light in solids is modulated by a ultra-short pump laser. It is used to study the transient optics, effective band structure in intense laser, ultra-fast dynamics of carrier et al. According to the general theory of interaction between solids and intense laser, the interaction strength between pump laser and solids can be classified, from weak to strong, as multi-photon regime, dynamic regime and tunneling regime, respectively. For multi-photon regime and dynamic regime, the intensity of pump laser is not so high and only electrons near the center Brillouin zone play effective role in band-band transition. Thus, in these regimes, the real band of solids can be simply replaced by parabolic band. However, in tunneling regime, many recent researches show that the electrons in Brillouin zone are all play important role and the parabolic approximation is no loner valid. Therefore, the real band structure of solids should be considered in tunneling regime. The parabolic band model is still used in present theories. So, it cannot be used in tunneling regime. In this application, the influence of real band structure of solids on ultrafast electro-absorption will be studied.

英文关键词： ultrafast electro-absorption;femtosecond laser;band structure of solids;high power laser;laser induced damage