It is demonstrated experimentally that a spin-torque nano-oscillator (STNO) rapidly sweep-tuned by a bias voltage can be used for time-resolved spectrum analysis of frequency-manipulated microwave signals with complicated multi-tone spectra. The critical reduction in the time of spectrum analysis comes from the naturally small time constants of a nano-sized STNO (1-100 ns). The demonstration is performed on a vortex-state STNO generating in a frequency range around 300 MHz, with frequency down-conversion and matched filtering used for signal processing. It is shown that this STNO-based spectrum analyzer can perform analysis of multi-tone signals, and signals with rapidly changing frequency components with time resolution on a μs time scale and frequency resolution limited only by the 'bandwidth' theorem. The proposed concept of rapid time-resolved spectrum analysis can be implemented with any type of micro and nano-scale frequency-swept oscillators having low time constants and high oscillation frequency.
@article{arxiv.2004.03508,
title = {Experimental demonstration of a rapid sweep-tuned spectrum analyzer with temporal resolution based on a spin-torque nano-oscillator},
author = {A. Litvinenko and V. Iurchuk and P. Sethi and S. Louis and V. Tiberkevich and J. Li and A. Jenkins and R. Ferreira and B. Dieny and A. N. Slavin and U. Ebels},
journal= {arXiv preprint arXiv:2004.03508},
year = {2023}
}