Enhanced terahertz magnetic near-field by tapered waveguide in double split-ring resonator coupled Tb3Ga5O12 crystal

We report on the enhancement of the terahertz magnetic near-field which is realized by a tapered waveguide. A Tb
₃
Ga
₅
O
₁₂
crystal coupled with a double split-ring resonator was pumped by this tightly confined terahertz field, and the magnetic near-field was measured via the magneto-optic sampling. With the use of the tapered waveguide, the amplitude of the magnetic near-field is enhanced by about 2 times on account of the focusing of the pumping terahertz field.