Controlling the dynamics of the plasmonic field in the nano-femtosecond scale by chirped femtosecond laser pulse

Abstract

Arbitrary control of the electromagnetic field in femto-nano scale has attracted significant research attention in nano-photonics. Although the electromagnetic field controlled in femto-nano scale could be realized by illuminating metallic nanoparticles with femtosecond chirped laser pulses, the quantitative relation of the laser chirp and the temporal evolution of the plasmonic field hasn’t yet been fully revealed. Here, active control of the localized plasmonic field is demonstrated by a chirped femtosecond laser pulse in an asymmetric Au nano-cross system within nm-fs scale using the finite differential time domain method. The transferring of the plasmonic field between the two poles of the nanocross is determined by the laser chirp and exhibits linear dependence on the time interval between the corresponding plasmonic resonant frequencies dispersed in the chirped laser pulse. The arrival time and amplitude of the peak field from the plasmonic hot spot are determined by the superposition of the induced field excited by the on-resonant and off-resonant frequency components distributed in the chirped laser pulse. The peak field would arrive behind the resonant frequency component for sufficient oscillation of the localized field. This relative delay between the resonant frequency and field peak is influenced by the temporal distribution of the resonant frequency in the chirped pulse and the response of localized field interpreted by the damped harmonic oscillator model. This result demonstrates that larger near-field enhancement is determined by not only the temporal sequence of the frequency component modulated by chirp but also the temporal distribution of the resonant frequency.

Real-time tracking of coherent oscillations of electrons in a nanodevice by photo-assisted tunnelling

“…A bound electronic system, such as plasmons in the nanoantenna junction with the restoring force from the ions of the nanoantennas, can be simply modelled as a driven damped harmonic oscillator 40 , 41 . The electric field of the plasmon oscillations ( E Pl ) can be expressed as; where is the resonance frequency of the plasmons, E Laser is the electric field of the driving laser pulse, and is the intrinsic damping rate of the plasmon oscillations, which is determined by the bandwidth of the spectrum of the plasmonic resonance.…”

Ultrafast Dynamics of Extraordinary Optical Transmission through Two-Slit Plasmonic Antenna

“…However, as for the dynamic behavior of EOT, it is currently an ongoing topic for exploring the potential capability to actively and flexibly manipulate the EOT in spatial-temporal regimes [ 17 ]. Recently, the femtosecond laser has discovered great potential for manipulating the dynamic properties of the surface plasmon resonance of nano-geometry [ 18 , 19 , 20 , 21 , 22 ]. Müller et al theoretically investigated the dynamics on a metallic transmission grating with femtosecond laser illumination and demonstrated the special importance of surface plasmon polariton (SPP) waves for controlling the spectral properties of EOT [ 23 ].…”

All-Optical Control of Ultrafast Switching between the Hybridized Plasmonic Fields of Au Nanorod Dimer in fs-nm Scale with Dispersed Femtosecond Laser

“…However, there are few reports on experimental observation of the ultrafast switching process (within femtosecond time scale) of a nanoscale hot spot and coherent control of its dynamic process. Flexible manipulation of the localized field with a large intensity contrast in nanostructure has the potential to realize an all-optical controlled modulator in a photonic circuit and chemical reaction in femtochemistry. − Intuitive observation of the ultrafast switching process with high spatiotemporal resolution is lacking, which limits the understanding of laser dispersion on the dynamics of the localized field. Quantitative control of the switching speed has not been achieved yet for the near field from the metal nanostructure with a chirped laser pulse.…”