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Abstract The advance of magnon spintronics requires understanding of time-domain magnon pulse transmission in order to develop high-speed information processing protocols. In this work, we demonstrate single-shot electrical detection of narrow-band magnon pulse transmission in a yttrium iron garnet thin-film delay line. The high signal-to-background ratio of magnon transmission band allows us to directly probe the magnon transmission electrically using a fast oscilloscope and to study its spectral evolution using Fast Fourier Transform (FFT) of the time-domain transmitted signal. At elevated input power, we show a magnon transmission reduction and a spectral distortion, which can be understood by the nonlinear magnon excitation in the transmission band defined by the antenna geometry. In addition, we also find that the higher- (lower-) frequency magnon spectral component exhibits a lower (higher) magnon group velocity, showing a dispersion agreeing with the Damon-Eshbach dependence. Our results provide important guidance of magnon pulse engineering for their applications in spin wave computing and coherent magnon information processing. 

Brillouin Light Scattering (BLS) spectroscopy is widely used for studying collective acoustic and magnetic excitations. In magnetism, it is employed as a versatile tool for measuring the characteristics of magnetic media, visualizing linear and nonlinear spin-wave spatiotemporal dynamics, investigating magnon–phonon interaction effects, and exploring fundamental phenomena such as the Bose–Einstein condensation of magnons. At the same time, magnetic BLS spectroscopy has so far suffered from a lack of possibilities to resolve short-wavelength magnons in arbitrary wavevector directions. Here, we demonstrate two-dimensional thermal magnon and phonon spectra measured in a single-crystal film of Yttrium Iron Garnet (Y3Fe5O12). The wide-range two-dimensional wavevector selectivity is accomplished in the backscattering geometry via independent rotations of the probing beam and the sample plane. The spectra were measured in the range of magnon and phonon wavelengths down to 400nm and are fully consistent with calculations that take into account exchange, dipole, and elastic interactions. Our results open the way to an in-depth study of the magnon, phonon, and magnon–phonon dynamics of solids.