Ferromagnetic resonance isolator based on a photonic crystal structure with terahertz vortices

A new terahertz isolator based on the ferromagnetic resonance effect is suggested and analyzed. A two-dimensional photonic crystal consisting of a square lattice of gallium arsenide rods has been employed in the design of the device. Incident electromagnetic waves interact with one magnetized ferrite rod and two stubs inserted in the photonic crystal structure, generating a vortex-like field profile in the ferrite rod. Electromagnetic signals propagating in the forward direction are transmitted with low insertion losses, while their propagation in the backward direction is not allowed due to the high losses of the ferrite rod operating at the ferromagnetic resonance regime. Computational simulations show that the operating bandwidth is equal to 0.87 GHz around the central frequency 106.6 GHz. In this frequency band, the insertion losses are lower than − 1.68 dB, the reflection levels are better than − 16 dB, and the isolation levels are greater than − 15 dB.