The transmission and tuning properties of an electrically-controlled terahertz modulator based on cross-shaped subwavelength hole array is investigated. The metal-semiconductor forms a Schottky junction

where the depletion region modifies the substrate conductivity through an external reverse voltage bias. This achieves effective control of the resonance enhanced terahertz transmission. We introduce a simulation method which combines electrical specification of the substrate and electromagnetic mechanism of the device. Our proof-of-concept modulator achieves an intensity modulation depth of 76% by changing the external voltage bias from 0 to 16 volts. In addition

the silicon substrate and relative simple device structure achieve reduced fabrication cost and difficulty. This design approach and device structure can be also translated to other terahertz and optical frequency range

especially in the optical frequencies

where the switching performance could be more promising.