Abstract

We report an active broadband terahertz modulator based on Fe₃O₄ nano-particles/Si structure, for which, the effects on it’s interface were measured in a THz time-domain spectroscopy system. As high as 92% modulation depth was achieved at an external excitation laser of 3.6 W/cm². This phenomenon can be explained by the accumulation of carriers in the interface of hybrid structure, which induce the intense absorption of terahertz transmission. The Fe₃O₄ nano-paricles thin film on Si substrate was easily attained by spin-coating widely commercial ferrofluids. The superior performance of this device on THz wave modulation compared to other terahertz modulators based on nano-materials and the ease of fabrication both illustrate that a promising method to modulate THz transmission has been realized.

© 2018 The Author(s)