Space-time duality in magnonics: Temporal diffraction in magnonic waveguides

•Propagation of short spin wave (SW) packets is governed by the laws of diffraction in compliance with the space–time duality.•Characteristic time delay τ<τchar=2πa2T0 (a is pulse’s half-width and T0=1ω0 its temporal period (λ in optics)) separates the near-field Fresnel (τ<τchar) and far-field (τ>τchar) Fraunhofer type of distortion of a magnonic pulse.•Temporal focusing (pulse compression and amplification) in the focal plane τfoc=ω0α2 can be done by introducing a linear phase modulation expit2α2.•By analogy with Fourier optics, a temporal lens forms in its “focal plane” a Fourier transform of the signal fed to the input of a magnonic waveguide.•The discovered functional features (ii) and (iii) open up new possibilities for the creation of a new generation of magnonic information processing devices.