Electronically Controlled Broadband Terahertz Amplitude Modulator Based on Ionic Liquid/PEDOT:PSS:DMSO Composite Structure

Electronically controlled modulation devices operating in the terahertz (THz) band offer a crucial foundation for the integration and minimization of THz systems. In this work, we offer a broadband THz amplitude modulator that can be electrically controlled. The modulator is based on a composite structure made of ionic liquid and polymer mixture poly (3-ethoxythiophenyl): poly (4-phenylsulfonate) (PEDOT: PSS: DMSO). By applying merely +4 V excitation and -4 V turn-off voltage, a 40% amplitude modulation depth may be produced in the frequency region of 0.1-1.5 THz due to the joint action of electrons in the polymer and ions in the ionic liquid. The measurement of the resistance change of the polymer surface provides an explanation and confirmation of the mechanism of polymer action in this occurrence. This work provides a material selection for a simple preparation, inexpensive, and effective modulation of THz amplitude for an ionic liquid gate electronic controlled THz modulator. It is also expected that this work can be helpful for the miniaturization and integration development of THz modulators.