CSuperGaussSpectrumPF(iOrder, sParameterName, fParamValue, Env)
  sParameterName = 'FWHM' - Pulse (intensity),
  or 'Waist', or 'TemporalParameter'
  iOrder = 1 - Gauss
 
  fParamValue - in Hz (angular frequency)
  or in s if 'TemporalParameter', 
 'TemporalParameter' = 1/ 'Waist'
 
  if Env is given the spectrum is square like in wavelengths