Enhanced Transmission and Reflection of Few-Cycle Pulses by a Single Slit

Abstract

We show that a physical mechanism responsible for the enhanced transmission and reflection of ultrashort (few-cycle) pulses by a single subwavelength slit in a thick metallic film is the Fabry-Perot-like resonant excitation of stationary, quasistationary, and nonstationary waves inside the slit, which leads to the field enhancement inside and around the slit. The mechanism is universal for any pulse-scatter system, which supports the stationary resonances. We point out that there is a pulse duration limit below which the slit does not support the intraslit resonance.

Modulated light transmission through a subwavelength slit at early stage

“…Suppose that the temporal full-width at half-maximum of its intensity is defined as ∆t. When ∆t ≥ t rt , the subunits partially overlap so that the temporal width of the observed field is effectively increased to be larger than that of the incident pulse [22]. When ∆t is short enough (e.g., ∆t t rt ), the whole pulse could be seen as a wave unit, and the subunits can barely interfere with each other.…”

“…Mechler et al [22] analyzed the transmission of Gaussian pulses with only a few light periods and pointed out that there are three regimes of resonant excitation according to their temporal pulse widths. In fact, the time-dependent analysis was obtained by the inverse Fourier transform from the solution of Neerhoff and Mur at each frequency, i.e., solving the phasor of the timeharmonic electric and magnetic fields from Maxwell's equations [23].…”

Visible light dynamical diffraction in a 1-D photonic crystal-based interferometer with an extremely thin spacer layer

“…Here it is interesting to mention that a cavity in the shape of a ten nanometer-sized slit in a conducting metal film also demonstrates optical properties which are inherent to a Fabry-Pérot resonator/interferometer [30][31][32]. Fig.…”

Resonant transmission of electromagnetic fields through subwavelength zero-ϵslits

“…The maximum transmission, τ max , seen contained within the continuous bright curve, is determined by examining the extrema of Eq. (13). By taking the appropriate derivative of the denominator, we find that τ max is determined by the transcendental equation, µqk 0 l = γ(q), where γ(q) = −Im[I 0 ]/|I 0 | 2 is a gradually increasing monotonic function of q.…”

“…As the geometrical parameters vary, the resonant wavelength can shift [10,11] in metals with slit perforations, as observed with microwaves [12]. For ultrashort incident pulses, the Fabry-Pérot-like modes can be resonantly activated [13] through the Fourier components of the wave packet inside the slit, leading in some cases to enhanced transmission. The resonant enhancement of a nanometer scale electromagnetic pulse was also shown to be spatially and temporally localized [14] in the near field.…”