| 研究実績の概要 |
Nonreciprocal photonic responses play a crucial role in advanced photonics applications, ranging from from one-way window to quantum computing. In non-centrosymmetric antiferromagnets (AFMs), nonreciprocity can manifest through nonlinear optical effects like second-harmonic generation (SHG), featured by varying efficiencies for spin-reversal domains. So far, techniques harnessing nonreciprocity-driven domain contrast are limited, and effective and flexible control over such nonreciprocity remains largely unachieved. Moreover, a comprehensive roadmap for controlling these nonreciprocal photonic behaviors from a material symmetry perspective is lacking. Drawing insights from group theory, we experimentally demonstrated a general method to modulate SHG domain contrast and nonreciprocity, using a prototypical van der Waals layered AFM MnPS3 as proof of concept. Through targeted application of electric field, we effectively manipulated the interferences among multipole SHG sources inherent in the crystal, directly changing the nonreciprocity. This approach offers distinct advantages, including broad-band feasibility, rapid response governed by electric signals, minimal device complexity, and a wide choice of antiferromagnet materials. Additionally, we have compiled a detailed listing of applicable magnetic point groups and optimal electric field orientations, establishing a guiding framework for electrically controlling nonlinear optical nonreciprocity in AFMs.
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