Chapter Six. Scattering with Interference

and others developed quantitative ways of coping, well before the photon had been conceived. Photon scattering can now accommodate all scattering phenomena, but as Johnsen points out, it is computationally messy. Chapter six is a tough one for those of us who belong to the rays and waves tradition. It includes transparency, reflection and refraction but is titled simply ‘Scattering with interference’. We are in quantal territory here. The first paragraph is wonderfully uncompromising, and I can’t resist quoting it in full:

Emil Zolotoyabko

D. S. Chemla, Alain D. Maruani, F. Bonnouvrier

We present the first evidence of interference between four- and six-wave mixing in multiple coherent scattering near the two-photon resonance of biexcitons in CuCl. The experimental data are quantitatively explained by taking proper account of propagation effects and by a model for ${\ensuremath{\chi}}^{(5)}$ involving no adjustable parameters.

K. T. Hecht