Chiral sculptured thin films (STFs) have unidirectionally periodic electromagnetic
constitutive properties and therefore exhibit the circular Bragg phenomenon.
Maxwell equations are solved using finite difference calculus
in order to establish the spatiotemporal anatomy of the action
of axially excited, chiral STF slabs on optical narrow-extent
modulating circularly polarized carrier waves. A Lorentzian
model was adopted for the permittivity dyadics of the
The time-domain manifestation
of the circular Bragg phenomenon is focussed on.
examining the refraction of NEPs by a chiral STF half-space,
a light pipe and the pulse bleeding phenomenon
are shown to occur -when the handednesses of the carrier wave
and the chiral STF coincide and the carrier wavelength is in the
vicinity of the center-wavelength of the Bragg regime. Next, pulse bleeding
inside a chiral STF slab is shown to be responsible for the
long wakes of reflected pulses and low energy contents of transmitted pulses,
when the incident wave spectrums significantly
overlap with the Bragg regime and the carrier waves
have the same handedness as the chiral STF slab. Thus,
a chiral STF slab can drastically
affect the shapes, amplitudes, and spectral
components of femtosecond pulses.