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

TL;DR

This paper explores how spin-orbit coupling influences type-II second-harmonic generation in vectorial laser modes, combining theoretical analysis and experimental validation to deepen understanding of SOC-mediated nonlinear optics.

Contribution

It provides a general theory for vectorial SHG driven by SOC and experimentally confirms the critical role of SOC in nonlinear optical interactions.

Findings

SOC significantly influences vectorial SHG processes

Theoretical predictions match experimental results

Foundation for future SOC-based nonlinear optical applications

Abstract

Vectorial nonlinear optics refers to the investigation of optical processes whose nonlinear polarization (NP) undergoes spin-orbit coupling (SOC) interactions where, in general, the driving light field or the new field generated by the interaction containing the SOC property. To contribute to fundamental knowledge in this domain, we examine the type-II second harmonic generation (SHG) induced by vectorial laser modes. First, we provide a general theory to analyze the vectorial SHG process. Second, by using two typical vector modes as examples, we show how the SOC of the pump field dictates nonlinear interaction. Finally, we corroborate our theoretical predictions through experiments to confirm the crucial role of the SOC in nonlinear interactions. These results enhance our fundamental understanding of SOC-mediated nonlinear optics and lay the foundation for further fundamental studies as well as possible applications.