标题： 通过瞬态吸收中的圆二色性进行飞秒全光谷极化检索 显示英文标题

标题： Attosecond All-Optical Retrieval of Valley Polarization via Circular Dichroism in Transient Absorption

摘要： 我们提出了一种方案，通过阿托秒圆二色性（CD）瞬态吸收光谱来检索二维六边形材料中的超快谷极化（VP）动力学。该方法基于由圆偏振探测脉冲引起的第一个导带和更高导带之间的CD跃迁。第一个导带中非等价谷的种群不平衡比例地映射到具有相反螺旋度的两个探测脉冲的吸收系数差异上，从而实现了前所未有的亚飞秒时间分辨率下对应VP动力学的定量检索。我们通过从头算计算在h-BN和MoS2中理论上证明了该方案，实现了VP动力学的准确检索，特别是瞬态VP切换过程，在250 as的时间分辨率下。 显示英文摘要

摘要： We propose a scheme for retrieving the ultrafast valley polarization (VP) dynamics in two-dimensional hexagonal materials via attosecond circular dichroism (CD) transient absorption spectroscopy. This approach builds on the CD transition between the first and higher conduction bands induced by the circularly polarized probe pulses. The population imbalance at nonequivalent valleys in the first conduction band is proportionally mapped onto the difference in absorption coefficients of two probe pulses with opposite helicities, supporting an unprecedented quantitative retrieval of the corresponding VP dynamics with subfemtosecond time resolution. We theoretically demonstrate the scheme for h-BN and MoS2 through ab initio calculations, achieving an accurate retrieval of the VP dynamics, particularly the transient VP switching processes, with a time resolution of 250 as.