Fig. 1: Hybrid device of plasmonic superconductor and the superconductivity modulation by plasmon excitation.

a Schematic of the gold nanoparticles (AuNPs)/hexagonal boron nitride (hBN)/NbSe₂ device under light illumination. b Optical image of a typical device A1 with a two-terminal measurement configuration and scanning electron microscope (SEM) image of the AuNPs organized on top of hBN/NbSe₂. The pink and cyan dashed lines outline the NbSe₂ and hBN flakes. c Left axis: Optical absorption spectra of the AuNPs on a quartz substrate. The black arrows denote the on (off)-resonant plasmon excitation by 532(1064)-nm light. Right axis: T_c modulation coefficient versus illumination wavelength. The error bars are obtained by the linear fittings in Supplementary Fig. 4. d–f Sample resistance R of device A1 as functions of temperature T and photon flux N₅₃₂ (N₁₀₆₄) under on(off)-resonant plasmon excitation by 532(1064)-nm light illumination. A contact resistance R_c = 54.5 Ω has been deducted. The white dashed lines denote the superconducting transitions where R reaches 50% of the normal state resistance. e–g Typical R-T curves for dark and on/off resonance cases (at the same photon flux of 4.68 × 10¹³ s⁻¹mm⁻²). h Superconducting critical temperature T_c versus photon flux N under on(off)-resonant plasmon excitation. T_c is defined by the temperature at which R reaches 50% of the normal state resistance. Linear fittings yield T_c modulation coefficients of −1.38 × 10⁻¹⁴ Ksmm² and −0.16 × 10⁻¹⁴ Ksmm² for on- and off-resonant plasmon excitations, respectively. i T_c modulation coefficient as a function of the number of layers of NbSe₂. The red circles and black squares are experimental data and theoretical predictions, respectively. The experimental data (red circles) are collected from twelve NbSe₂ devices with different thicknesses. The error bars are obtained by the same method as in c.