Fig. 3: Electromechanically reconfigurable optical nano-kirigami.

a Calculated and b experimental reflection spectra in normal direction for a pinwheel array under different DC voltages as noted. Inset, calculated electric field distributions in the xz-plane (y = 0) under V = 0 and 31 V (with Δd = 300 nm and λ = 750 nm), respectively. Image size: 2.5 × 2 μm². The distorted wave shape at V = 31 V indicates the diffraction to other directions under deformations since \(\lambda \ll w\) (see Supplementary Fig. 6a). In experiments, the reflection stops changing when V > 32 V and the spectrum increases back to the initial 0 V condition after turning off the voltage at 35 V. c Amplitude of modulation contrast (defined as \(\left| {\Delta {{R}}/{{R}}} \right|\)) versus applied voltage at λ = 750 nm. Inset, modulation contrast versus time when the voltage is turned on and off at 20 V and λ = 550 nm. d Calculated vertical displacement (Δd) versus applied voltage for a pinwheel and a type-i spiral, respectively, of which the pull-in voltages are identified at 35 and 73 V. Inset, simulated structures with corresponding maximum Δd (units: nm). e Calculated (Cal) and experimental (Exp) reflection spectra of the type-i spirals in the inset of f under V = 0 and 60 V (with Δd = 70 nm), respectively. Inset, electric field distributions of the 2D and 3D spirals in xy-plane (z = 0) at λ = 1842 nm. Image size: 1.5 × 1.5 μm². f Modulation contrast versus wavelength when the DC voltage varies with a sequence 40 → 0 → 50 → 0 → 60 → 0 V (from bottom to top). Structural parameters: w = 2 µm, p = 2.5 µm, d = 300 nm for pinwheels; w = 1.225 µm, p = 1.5 µm, d = 300 nm for spirals. Scale bar: 1 µm.