obj = CLorentzPF(sParameterName, fParamValue)
  obj = CLorentzPF(sParameterName, fParamValue, sType)
 
  sParameterName = 'FWHM'/ 'LorentzParam'
  sType = 'Intensity' (default) / 'Amplitude' - choose wether
  the intensity of light or the amplitude of electric field
  should have an L shape.
 
  note that for 'Intensity'  'FWHM' / 2 gives 'LorentzParam'
  this is not the case for 'Amplitude' where:
  'LorentzParam' = 'FWHM' / 2 / sqrt(sqrt(2) - 1);