v 5.3

$${E_1=E_{10} \exp[i(\omega t - {\bf k}_1 {\bf r} + \delta_1 )] = E_{10} \exp(i\varphi_1 ) \exp(i\omega t)\\ E_2=E_{20} \exp[i(\omega t - {\bf k}_2{\bf r} + \delta_2 )] = E_{20} \exp(i\varphi_2 ) \exp(i\omega t)}$$