We set out to achieve a strong magnon-photon coupling (polariton states) at terahertz (THz) frequencies using Fabry-Perot type cavities and antiferromagnetic (AF) crystals. Such polariton states can be exploited for quantum applications like computing, memories, transducers or sensing, i.e. operations on single photons or single quasiparticles of matter waves. In the THz range such a coupling still remains to be documented in depth. Also, we lack experimental data on THz magnon polaritons that have an advantage of narrow linewidths - a parameter crucial for possible quantum applications. Therefore, in the first stage of this project we will attempt to observe magnon-polaritons using THz optical methods. In the next stage, an electrical detection of magnetic polaritons will be undertaken with two approaches: (i) heavy metal layers will support detection of magnetic excitations as it is commonly practiced in spintronics; (ii) two-dimensional materials/structures with plasma resonances will serve as detectors - in these structures, we will be also looking for magnon-plasmon coupling. Electrical detection of polariton states is important because employing strong coupling into the AF spintronics might offer better responsivities to THz radiation and provide a tool for manipulating of AFs properties that may further enhance spintronic devices. Possible magnon-plasmon coupling could allow for information transfer between THz magnetic and plasmonic excitations.