Polarization-tunable THz emitters composed of ferromagnetic heterostructures and liquid crystals

摘要

We demonstrate a magnetically and electrically polarization-tunable terahertz emitter that integrates a ferromagneticheterostructure and large birefringence liquid crystals.The ferromagnetic heterostructure acts as the THz source aswell as the electrode on the optical pumping side. The liquidcrystal cell acts as the phase retarder. The state of thepolarization can be switched between liner and circularpolarization by changing the direction of the external magneticfield in a non-contact way. The phase retardation betweene and o wave can be electrically tuned with a highefficiency. This compact and economical THz emitter canbe widely used for polarization sensitive researches andengineering applications.