Dynamic tomography of the spin-orbit coupling in nonlinear optics

Abstract

Spin-orbit coupling (SOC) light fields with spatially inhomogeneous polarization have attracted increasing research interest within the optical community. In particular, owing to their spin-dependent phase and spatial structures, many nonlinear optical phenomena which we have been familiar with up to now are being re-examined, hence a revival of research in nonlinear optics.To fully investigate this topic, knowledge on how the topological structure of the light field evolves is necessary, but, as yet, there are few studies that address the structural evolution of the light field. Here, for the first time, we present a universal approach for theoretical tomographic treatment of the structural evolution of SOC light in nonlinear optics processes. Based on a Gedanken vector second harmonic generation, a fine-grained slice of evolving SOC light in a nonlinear interaction and the following diffraction propagation are studied theoretically and verified experimentally, and which at the same time reveal several interesting phenomena. The approach provides a useful tool for enhancing our capability to obtain a more nuanced understanding of vector nonlinear optics, and sets a foundation for further broad-based studies in nonlinear systems.

Heralded Generation of Vectorially Structured Photons With a High Purity

“…However, due to the absence of SLM, this prism interferometer can only work for controlling the CV modes. Namely, this prism-based interferometer can be regarded as an integrated version of the Sagnac loop used in our recent experiments [28][29][30].…”

Spatial-Polarization-Independent Parametric Up-Conversion of Vectorially Structured Light

“…It should be noted that while long periodically poled crystals are high efficiency, they are not easy to devise in the two-crystal scheme because they introduce a Rayleigh-distance shift between the orthogonal polarization components of the SHG. In view of this, we have also demonstrated, both theoretically and experimentally, the SHG of vector light based on the Sagnac scheme with a thin type-I crystal, as well as a long type-0 crystal [37,38].…”

“…Notably, despite these works realized the SHG of vector light, compared with the input signal, the SOC state of the output SHG was also transformed. The transformation rule of the SOC state depends on the SoP reference frame of both the input signal and the converting apparatus [37]. However, for vector light (or photons) carrying classical (or quantum) information, the fundamental requirement for upconversion is that the apparatus does not disturb the other DoFs of the signals, especially for the SOC states.…”

Vectorial nonlinear optics: Type-II second-harmonic generation driven by spin-orbit-coupled fields

“…But the difference is that owing to the wide difference in the power densities of LG modes with different values of , the impacts of , the generated SHG fields both carry multi topological charges. Therefore, due to -dependent Gouy phase accumulation, the SHG beam profiles experience a 90 rotation from 0 z to the far field [35]. (b) Simulated SOC structures of FP-mode pumps for different angles 12  , their corresponding SoP-dependent orthogonal spatial mode pairs, and spatial profiles of NPs driven by them.…”

“…These SOCmediated NPs, on the one hand, introduce a host of vector nonlinear optical phenomena and rich functionalities that have no analog in scalar interactions, and, on the other hand, provide a promising way to generate, control, and characterize structured light. As a consequence, this emerging field has garnered growing interest in research and revived work on fundamental nonlinear optics [32][33][34][35][36][37][38][39][40][41][42][43][44].…”