Ferroelectric Domain Control of Nonlinear Light Polarization in MoS2 via PbZr0.2Ti0.8O3 Thin Films and Free‐Standing Membranes

Abstract Two‐dimensional (2D) transition metal dichalcogenides (TMDCs) such as MoS 2 exhibit exceptionally strong nonlinear optical responses, while nanoscale control of the amplitude, polar orientation, and phase of the nonlinear light in TMDCs remains challenging. In this work, by interfacing monolayer MoS 2 with epitaxial PbZr 0.2 Ti 0.8 O 3 (PZT) thin films and free‐standing PZT membranes, the amplitude and polarization of the second harmonic generation (SHG) signal are modulated via ferroelectric domain patterning, which demonstrates that PZT membranes can lead to in‐operando programming of nonlinear light polarization. The interfacial coupling of the MoS 2 polar axis with either the out‐of‐plane polar domains of PZT or the in‐plane polarization of domain walls tailors the SHG light polarization into different patterns with distinct symmetries, which are modeled via nonlinear electromagnetic theory. This study provides a new material platform that enables reconfigurable design of light polarization at the nanoscale, paving the path for developing novel optical information processing, smart light modulators, and integrated photonic circuits.