Nonreciprocal nano-optics with spin-waves in synthetic antiferromagnets

TL;DR

This paper demonstrates a versatile platform using spin-waves in synthetic antiferromagnets for wavefront engineering, focusing, and interference, highlighting their potential for nanoscale optically-inspired devices with robust interference patterns.

Contribution

It introduces a novel magnonic platform utilizing tailored spin-textures for controlling spin-waves, emphasizing nonreciprocity and resilience to back-reflection in synthetic antiferromagnets.

Findings

Demonstrated wavefront shaping and focusing of spin-waves

Achieved diffraction-limited spin-wave beams and interference patterns

Showed resilience of interference patterns due to nonreciprocity

Abstract

Integrated optically-inspired wave-based processing is envisioned to outperform digital architectures in specific tasks, such as image processing and speech recognition. In this view, spin-waves represent a promising route due to their nanoscale wavelength in the GHz frequency range and rich phenomenology. Here, we realize a versatile optically-inspired platform using spin-waves, demonstrating the wavefront engineering, focusing, and robust interference of spin-waves with nanoscale wavelength. In particular, we use magnonic nanoantennas based on tailored spin-textures for launching spatially shaped coherent wavefronts, diffraction-limited spin-wave beams, and generating robust multi-beam interference patterns, which spatially extend for several times the spin-wave wavelength. Furthermore, we show that intriguing features, such as resilience to back-reflection, naturally arise from the spin-wave nonreciprocity in synthetic antiferromagnets, preserving the high quality of the interference patterns from spurious counterpropagating modes. This work represents a fundamental step towards the realization of nanoscale optically-inspired devices based on spin-waves.