近日，韩国科学技术院（KAIST）Ra, Young-Sik团队研究了完整表征多模二阶非线性光学量子过程。相关论文于2025年11月11日发表在《自然—光子学》杂志上。

多模光学过程的完整表征为理解复杂的光学现象铺平了道路，从而导致了新型光学技术的发展。然而，到目前为止，表征主要集中在线性光学过程，尽管非线性光学过程对光子技术很重要。

研究组报告了多模二阶非线性光学量子过程的完整实验表征-也称为玻色子高斯通道。他们的阻抗高效表征方法在16模量子过程中得到了证明，捕获了非幺正量子演化的全部信息，满足了所需的物理条件。这种完整的表征可以识别特征正交及其相关的放大和噪声特性。

此外，研究组通过表征各种非线性光学量子过程，包括热态产生，非线性相互作用的模式相关损耗和量子噪声通道，证明了该方法的广泛适用性。这种方法为表征非线性光学过程提供了一种通用而有效的技术，将有利于发展可扩展的光子技术。

附：英文原文

Title: Completely characterizing multimode second-order nonlinear optical quantum processes

Author: Gwak, Geunhee, Roh, Chan, Yoon, Young-Do, Kim, M. S., Ra, Young-Sik

Issue&Volume: 2025-11-11

Abstract: Complete characterization of a multimode optical process has paved the way for understanding complex optical phenomena, leading to the development of novel optical technologies. Until now, however, characterizations have mainly focused on linear optical processes, despite the importance of nonlinear optical processes for photonic technologies. Here we report the complete experimental characterization of multimode second-order nonlinear optical quantum processes—also known as bosonic Gaussian channels. Our resource-efficient characterization method, demonstrated on a 16-mode quantum process, captures the full information of non-unitary quantum evolution and satisfies the required physical condition. This complete characterization enables the identification of eigenquadratures and their associated amplification and noise properties. Moreover, we demonstrate the broad applicability of our method by characterizing various nonlinear optical quantum processes, including cluster-state generation, mode-dependent loss with nonlinear interaction and a quantum noise channel. Our method, by providing a versatile and efficient technique for characterizing a nonlinear optical process, will be beneficial for developing scalable photonic technologies.

DOI: 10.1038/s41566-025-01787-x

Source: https://www.nature.com/articles/s41566-025-01787-x