In this letter, we report the room-temperature operation of an electrically controlled THz modulator. The modulation is achieved by reducing the electron density in a gated two-dimensional electron gas structure, which leads to an increase in the transmitted intensity of an incident beam of THz radiation. By depleting an electron gas of density 1012cm−2, we achieved a maximum modulation depth of 3% for a pulse of terahertz radiation covering the range of frequencies from 0.1 to 2 THz.

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