Tunable bandstop filtering specialities in superconducting Thue–Morse photonic multilayers

We theoretically investigate wide and tunable bandstop filters based on one-dimensional superconducting photonic multilayers. These multilayers are composed of superconductors (Nb) and semiconductors (GaAs), arranged in accordance with the Thue–Morse sequence. The wide transmission bandgap of the multilayers can be utilized as a bandstop filter, with greater accuracy achieved by larger sequence number and thinner semiconductor. Our results demonstrate that both the bandwidth and center frequency decrease as the ambient temperature and semiconductor thickness increase. Especially, the stopband disappears when the temperature exceeds the critical temperature (Tc) of Nb. On the other hand, increasing hydrostatic pressure and superconductor thickness leads to monotonous increases in both the bandwidth and center frequency. Moreover, for thin superconductors or high temperatures close to Tc, the quality factor is high and tunable in a wide range. Our work presents a flexible solution for optical bandstop filters, which may also find potential applications in optical switching and modulating. •Wide bandstop filters are achieved based on the transmission bandgap of 1D superconducting photonic multilayers.•Both the bandwidth and center frequency decrease as the ambient temperature and semiconductor thickness increase.•Quality factor of the bandstop filter is high and tunable for ultrathin superconductors or temperatures close to the critical temperature.