Terahertz-Frequency Signal Source Based on an Array of Antiferromagnetic Spin Hall Oscillators

Abstract

Terahertz-frequency (TF) signals have many promising applications in applied physics and technology. However, to date, there are no rather large-power (>100$\mu$W) compact and reliable sources of coherent TF radiation. One of the prospective approaches to develop such TF signal sources is based on the utilization of magnetic dynamics in the spin Hall oscillators (SHOs) based on antiferromagnets (AFMs). While a single antiferromagnetic SHO can typically emit output TF signal power $\sim10\mu$W or less, this power can be substantially improved if an array of synchronized SHOs is used. In this paper, we evaluate the output power of a TF signal source based on an array of antiferromagnetic SHOs embedded in a high-Q dielectric resonator and consider two limiting cases: the case of independent SHOs and the case of ideal phase-locked SHOs. Our calculations show that even a small number ($\leq$10) of synchronized SHOs embedded in a high-Q dielectric resonator can provide output TF signal power of $\sim100-1000\mu$W (depending on their operation frequency), which might be sufficient for the majority of practical applications.