  Understanding the ultrafast processes at their natural-time scale is crucial
for controlling and manipulating nanoscale optoelectronic devices under
light-matter interaction. Here, we demonstrate that ultrafast plasmon
resonances, attributed to the phenomenon of Extraordinary Optical Transmission
(EOT), can be significantly modified by tuning the spectral and temporal
properties of the ultrashort light pulse. In this scheme, all-optical active
tuning governs spatial and temporal enhancement of plasmon oscillations in the
EOT system without device customization. We analyze the spectral and temporal
evolution of the system through two approaches. First, we develop a theoretical
framework based on the coupled harmonic oscillator model, which analytically
describes the dynamics of plasmon modes in the coupled and uncoupled state.
Later, we compare the evolution of the system under continuous wave and pulsed
illumination. Further, we discuss time-resolved spectral and spatial dynamics
of plasmon modes through 3D-FDTD simulation method and wavelet transform. Our
results show that optical tuning of oscillation time, intensity, and spectral
properties of propagating and localized plasmon modes yields a 3-fold
enhancement in the EOT signal. The active tuning of the EOT sensor through
ultrashort light pulses pave the way for the development of on-chip photonic
devices employing high-resolution imaging and sensing of abundant atomic and
molecular systems.
