Strong light confinement and optical force enhancement in phosphorene with acoustic plasmons

Abstract

Abstract We analytically and numerically investigate the acoustic plasmon mode in phosphorene placed above a metallic substrate with a finite gap width. Combined with finite-difference time-domain simulations, we demonstrate the responses of evanescent waves in the phosphorene-insulator-metal (PIM) waveguide, involving field enhancement, light confinement, and optical force. It turned out that owing to a large amount of light energy squeezed inside the gap, the light confinement ratio and optical force along the armchair direction in the PIM waveguide can be up to 96% and 6930 pN mW−1, respectively. Our results may manifest in diverse optoelectronic applications like optical tweezers.