Fresnel diffraction of spin waves

Abstract

The propagation of magnetostatic forward volume waves excited by a constricted coplanar waveguide is studied via inductive spectroscopy techniques. A series of devices consisting of pairs of sub-micrometer size antennae is used to perform a discrete mapping of the spin wave amplitude in the plane of a 30-nm thin YIG film. We found that the spin wave propagation remains well focused in a beam shape of width comparable to the constriction length and that the amplitude within the constriction displays oscillations, two features which are explained in terms of near-field Fresnel diffraction theory.

Controlled interconversion of quantized spin wave modes via local magnetic fields

“…Supplementary Movies1. Corresponding animation of the first three odd modes (n=1, 3,5) and the summation of the odd modes (n=1, 3,5,7,9,11) spatial normalized magnetization distribution in YIG microstripe as shown Fig. 1(c) in one period.…”

“…[1][2][3][4] Additional functionality can be gained from the fact that spin waves can also be coupled to other wave-like excitations, such as photons 5,6 and phonons. 7 Furthermore, many classical wave phenomena, such as diffraction, 8,9 reflection and refraction, [10][11][12] interference 13,14 and the Doppler effect 15,16 were observed with spin waves. At the same time, quantum mechanical interactions, such as the magnon scattering [17][18][19] and their interactions with other quasiparticles 20 were observed as well, and provide additional avenues for utilizing spin waves.…”

Optically Inspired Nanomagnonics with Nonreciprocal Spin Waves in Synthetic Antiferromagnets

“…To exploit the rich phenomenology of spin waves for integrated optically inspired processing, generating coherent spatially engineered wavefronts and controlling the propagation and interference of multiple spin‐wave beams are crucial. In addition, nonreciprocity, arising from the dipolar interactions, nonreciprocal coupling between spin waves and antennas, and the breaking of the top/bottom symmetry of the ferromagnetic films, represents an additional degree of freedom for the realization of devices.…”

“…[6] On the other hand, spin waves offer the potential for nanoscale integrability and provide an interesting physical system for developing unconventional computational frameworks, such as neural networks and reservoir computing. [7] To exploit the rich phenomenology of spin waves [8][9][10][11][12][13][14] for integrated optically inspired processing, generating coherent spatially engineered wavefronts and controlling the propagation and interference of multiple spin-wave beams are crucial. In addition, nonreciprocity, arising from the dipolar interactions, [15][16][17][18] nonreciprocal coupling between spin waves and antennas, [12] and the breaking of the top/ bottom symmetry of the ferromagnetic films, [19] represents an additional degree of freedom for the realization of devices.One of the most versatile methods for spin-wave emission is based on using patterned shaped microantennas, for generating a localized oscillating magnetic field in correspondence Integrated optically inspired wave-based processing is envisioned to outperform digital architectures in specific tasks, such as image processing and speech recognition.…”

Reversible tuning of omnidirectional band gaps in two-dimensional magnonic crystals by magnetic field and in-plane squeezing

“…The last one means the depen-dence on the direction and length of the wave vector k. Such propagation effects can lead to several interesting features in planar magnetic systems, e.g., the virtual separation of the thin film into subsystems and the band collapse, [38][39][40] the mirage effect, 41 the spin-wave lensing and flow control. [42][43][44][45][46] The aim of the current work is to explain the influence of the squeezing and the external field change on the mode softening in the context of propagation effects. We study mechanisms of the k-dependent frequency shift in the spin-wave spectrum and show these mechanisms to be useful for the design and tuning of the omnidirectional magnonic gaps.…”