近日，西班牙巴塞罗那科技学院的J. Rivera-Dean与广东以色列理工学院的M. F. Ciappina等人合作并取得一项新进展。他们对激发态原子系统中，高次谐波产生后光的压缩态进行了研究。相关研究成果已于2024年12月23日在国际知名学术期刊《物理评论A》上发表。

据悉，高次谐波产生（HHG）近期作为一种前景广阔的方法崭露头角，能够生成涵盖从红外到极紫外波段频率的非经典光态。

在这项工作中，研究人员从理论上探讨了通过将被初始激发至第一激发态的原子系统中的，高次谐波产生（HHG）过程来生成光的压缩态。研究表明，在驱动场和低阶谐波模式中均存在显著的单模压缩现象。

此外，研究人员还描述了生成态中的双模压缩特性，包括基频模式与谐波模式之间，以及谐波模式相互之间的压缩特性。利用这些相关性，研究人员通过预报测量（特别是通过在受双模压缩影响的其中一个模式中进行光子减法）展示了光学薛定谔猫态的生成。

附：英文原文

Title: Squeezed states of light after high-order harmonic generation in excited atomic systems

Author: J. Rivera-Dean1,*, H. B. Crispin2,3,4,5,6, P. Stammer1,7, Th. Lamprou8, E. Pisanty9, M. Krüger4,5,6, P. Tzallas8,10, M. Lewenstein1,11, and M. F. Ciappina2,3,4,†

Issue&Volume: 2024-12-23

Abstract: High-harmonic generation (HHG) has recently emerged as a promising method for generating nonclassical states of light with frequencies spanning from the infrared up to the extreme ultraviolet regime. In this work, we theoretically investigate the generation of squeezed states of light through HHG processes in atomic systems that were initially driven to their first excited state. Our study reveals significant single-mode squeezing in both the driving field and low-order harmonic modes. Additionally, we characterize two-mode squeezing features in the generated states, both between fundamental and harmonic modes, and among the harmonic modes themselves. Using these correlations, we demonstrate the generation of optical Schrdinger kitten states through heralding measurements, specifically via photon subtraction in one of the modes influenced by two-mode squeezing.

DOI: 10.1103/PhysRevA.110.063118

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.063118