Enhancement of higher order nonlinear susceptibilities are investigated in three level quantum well with a ladder
configuration in the regime of electromagnetically induced transparency. We have identified the existence of giant
third and fifth order nonlinear susceptibilities of the order ~10<sup>-22 </sup> <i>m</i><sup>4</sup>/<i>V</i><sup>4</sup> at pump wavelength of 9.6 <i>μm</i>. The
group velocity is reported to be slowed down by 10<sup>4</sup> times compared to the speed of light in vacuum.
This paper presents an investigation of broadband supercontinuum (SC) generation in photonic crystal fibers using cosh-Gaussian optical pulses. It is found that the SC spectra of these cosh-Gaussian pulses are composed of several internal oscillations. The number of the oscillations increases with an increase in the value of the cosh parameter Ω0. The internal structure of the SC spectra shows an asymmetric behavior, possessing fewer oscillations as we move from the lower to higher wavelength region. Our results indicate that the SC generation dynamics is dominated by self-phase modulation.