Active Tunable Extraordinary Optical Transmission in the Visible Regime

Active tuning of components in the photonic integrated circuits (PICs) is crucial for achieving programmable devices, especially in the visible regime [1]. However, the operational bandwidth and response time of photonic devices remains fixed after manufacturing [2]. In this study, we demonstrate (i) all-optical and (ii) electro-optical control of extraordinary optical transmission (EOT) in the visible regime for on-demand tunable and scalable PICs. In the all-optical control scheme, the intensity and spectral position of the EOT signal are dynamically tuned by modifying the dynamics of surface plasmon resonances (SPR) in the EOT structure through ultrashort light pulse. The degrees of freedom for such optical control are the temporal shape, duration, and spectral bandwidth of the ultrashort pulse. Using a coupled harmonic oscillator model, we develop a theoretical framework to describe the dynamics of localized (LSP) and propagating (SPP) plasmon mode in the EOT structure under continuous wave (CW) and pulsed illumination. Further, we discuss time-resolved spatial and temporal dynamics of plasmon modes through 3D-finite difference time domain (FDTD) simulations and wavelet transform. Our results show that modulating the spectral bandwidth (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda_{exc}$</tex>) and duration (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\tau$</tex>) of optical pulse tune the spectral and temporal properties of SPP and LSP modes which not only enhance the EOT signal efficiency to 95% but also improves it response time by increasing the lifetime of fast decaying SPR up to 100 fs [3].