近日，以色列理工学院的Ido Kaminer及其研究小组取得一项新进展。经过不懈努力，他们探究由量子光驱动的高次谐波产生过程。相关研究成果已于2023年8月3日在国际知名学术期刊《自然—物理学》上发表。

该研究团队表明，高次谐波产生（HHG）的定义光谱特征，如高原和截止现象，对光的量子态很敏感。虽然相干光态和福克光态可以诱导HHG截止律，但热和压缩态会对其产生影响，使其被延长。相比相同强度的相干光态，这些状态能够产生更高的谐波。因此，通过塑造光的量子态可以产生更高的谐波。研究人员发展了由压缩光驱动的极端非线性光学理论，更一般地说是由任意量子态光驱动的理论，并引入了驱动场的量子态作为自由度。

据悉，高次谐波产生（HHG）是一种极端非线性过程，通过强脉冲光驱动物质发出高次谐波，达到极紫外和X射线光谱范围。迄今为止，HHG一直是由经典的电磁场产生的强激光脉冲所驱动。然而，光的量子态在强光与物质的非摄动相互作用中的作用仍未被探索。

附：英文原文

Title: High-harmonic generation driven by quantum light

Author: Gorlach, Alexey, Tzur, Matan Even, Birk, Michael, Krger, Michael, Rivera, Nicholas, Cohen, Oren, Kaminer, Ido

Issue&Volume: 2023-08-03

Abstract: High-harmonic generation (HHG) is an extreme nonlinear process in which intense pulses of light drive matter to emit high harmonics of the driving frequency, reaching the extreme ultraviolet and X-ray spectral ranges. So far, HHG has always been generated by intense laser pulses that are well described as a classical electromagnetic field. However, the role of the quantum state of light in non-perturbative interactions of intense light with matter has remained unexplored. Here we show that the defining spectral characteristics of HHG, such as the plateau and cutoff, are sensitive to the quantum state of light. While coherent and Fock light states induce the established HHG cutoff law, thermal and squeezed states substantially surpass it, extending the cutoff compared with a coherent light state of the same intensity. Shaping the quantum state of light thus enables the production of far higher harmonics. We develop the theory of extreme nonlinear optics driven by squeezed light, and more generally by arbitrary quantum states of light, introducing the quantum state of the driving field as a degree of freedom.

DOI: 10.1038/s41567-023-02127-y

Source: https://www.nature.com/articles/s41567-023-02127-y