An on-chip reconfigurable meta-absorber for optical switch, information authentication, all-optical logic, and...

We present a reconfigurable meta-absorber (RMA) based on electric split-ring resonators (eSRRs), each featuring a central cantilever and two lateral cantilevers. By applying a DC bias voltage, the cantilevers are bent downward, effectively changing their lengths. Under transverse magnetic illumination, varying the length of the central cantilever continuously tunes the main resonant wavelength from 3.857 μm to 5.692 μm. At fixed wavelengths, the absorptivity can be controlled by altering the polarization angle of the incident light, enabling operation as an optical switch. When the lengths of two lateral cantilevers are simultaneously adjusted, it produces resonant wavelength shifts of approximately 300 nm. Information encryption can be achieved by appropriately adjusting the states of the cantilever and incident wave. Additionally, by encoding different combinations of cantilever lengths and incident polarization modes as input signals, and using the resulting absorptivity for logic readout, the device realizes seven distinct logic gates. Moreover, the RMA exhibits a high sensitivity up to 1.80 μm per RIU to the refractive index change of the surrounding medium. The design of the RMA offers a viable pathway toward integrating optical switching, information authentication, opto-logic functions and sensing on a single chip.