Voltage-actuated thermally tunable on-chip terahertz filters based on a whispering gallery mode resonator

A tunable integrated terahertz (THz) filter is one of the basic elements for realizing integrated reconfigurable THz communication systems. The state-of-the-art tunable THz filters are discrete or vertically pumped for integrated devices. Here, we propose and demonstrate voltage-actuated thermally tunable on-chip THz bandpass and bandstop filters based on a whispering gallery mode resonator. The quality factors of the bandpass and bandstop filters attain 1867 and 1909, respectively, at approximately 0.4795 THz. Widely continuous tunability is realized by adjusting the voltage applied to a micro-heater. As far as we know, this is the first Letter on on-chip tunability in the THz domain. It provides a simple and reliable tuning method for on-chip THz devices. Furthermore, the implementation of tunable bandpass and bandstop filters plays an important role in THz signal processing.