Efficient Co/Pt THz spintronic emitter with tunable polarization

We report on the design of a spintronic emitter based on the Pt(3nm)/Co(3nm) structure, which enables the control over terahertz radiation polarization. Utilizing the field-induced magnetization rotation that takes place at low magnetic fields of up to 250Oe at room temperature, we have achieved the full range of terahertz polarization rotation from 0 degrees to 360 degrees. This rotation became possible due to the uniaxial magnetic anisotropy induced in the plane of the cobalt film during its fabrication. We evaluated the efficiency of the Co/Pt structure in generating terahertz radiation and found that the terahertz pulse energy flux reaches similar to 160 nJ/cm(2) at an excitation flux of 4 mJ/cm(2).