Liao Chen-Ting, Sandhu Arvinder, Camp Seth, Schafer Kenneth J, Gaarde Mette B
College of Optical Sciences and Department of Physics, University of Arizona, Tucson, Arizona 85721, USA.
Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
Phys Rev Lett. 2015 Apr 10;114(14):143002. doi: 10.1103/PhysRevLett.114.143002. Epub 2015 Apr 6.
We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared (IR) field. We study the interplay between the IR-induced phase shift of the microscopic time-dependent dipole moment and the resonant-propagation-induced reshaping of the macroscopic XUV pulse. Our experimental and theoretical results show that as the optical depth increases, this interplay leads initially to a broadening of the IR-modified line shape, and subsequently, to the appearance of new, narrow features in the absorption line.
我们通过使用极紫外（XUV）阿秒脉冲序列来探测在强红外（IR）场影响下的光学厚氦靶，研究了超越单原子响应的激光修饰原子的吸收线形状。我们研究了红外诱导的微观时间相关偶极矩的相移与共振传播诱导的宏观XUV脉冲重塑之间的相互作用。我们的实验和理论结果表明，随着光学深度的增加，这种相互作用最初导致红外修饰线形状的展宽，随后导致吸收线中出现新的窄特征。
