Singh Sachleen, Nape Isaac, Forbes Andrew
Opt Express. 2025 Jun 30;33(13):27615-27625. doi: 10.1364/OE.562028.
Tailoring the degrees of freedom (DoF) of light for a desired purpose, so-called structured light, has delivered numerous advances over the past decade, ranging from communications and quantum cryptography to optical trapping and microscopy. The shaping toolkit has traditionally been linear in nature, only recently extended to the nonlinear regime, where input beams overlap in a nonlinear crystal to generate a structured output beam. Here we show how to enhance the fidelity of the structured output by aligning light with light. Using orbital angular momentum modes and difference frequency generation as an example, we demonstrate precise control of the spatial overlap in both the transverse and longitudinal directions using the structure of one mode as a virtual structured (in amplitude and phase) light-based aperture for the other. Our technique can easily be translated to other structured light fields as well as alternative nonlinear processes such as second harmonic generation and sum frequency generation, enabling advancements in communication, imaging, and spectroscopy.
为了实现特定目的而调整光的自由度（DoF），即所谓的结构化光，在过去十年中取得了众多进展，涵盖从通信和量子密码学到光学捕获和显微镜等领域。传统上，整形工具本质上是线性的，直到最近才扩展到非线性领域，即输入光束在非线性晶体中重叠以产生结构化输出光束。在这里，我们展示了如何通过光与光的对齐来提高结构化输出的保真度。以轨道角动量模式和差频产生为例，我们利用一种模式的结构作为另一种模式基于光的虚拟结构化（幅度和相位）孔径，演示了在横向和纵向方向上对空间重叠的精确控制。我们的技术可以很容易地应用于其他结构化光场以及诸如二次谐波产生和和频产生等替代非线性过程，从而推动通信、成像和光谱学的发展。
