An electro-optic tunable microwave delay-line using the piezoelectric-piezomagnetic superlattices with an external DC electric field

An Electro-optic tunable microwave slow-light delay-line using the piezoelectric (PZT) and piezomagnetic (CoFe2O4) superlattices (PPSs) with the external DC electric field is presented. Asymmetric coupled polaritonic band structures with respect to the forward and backward directions are induced by timespace inversion symmetry breaking due to the coexistence of ferroelectric and ferromagnetic domains. The group velocity and time-delays of electromagnetic waves in the proposed PPSs can be tuned freely by the external DC electric field via the electro-optic effect. The tunability is continuous and reversible. Thus, the proposed PPSs has a switch function that can realize the free switching between fast and slow waves by the external DC electric field. The slow-wave factors with regard to the forward and backward directions are also asymmetric. In addition, transmission spectra show that the proposed PPSs have an electro-optic tunable wavelength selection function. (C) 2020 Elsevier B.V. All rights reserved.