$${E = E_0 \exp[i(\omega t- {\bf k} {\bf r})]=E_0 \exp \bigg[i\omega \bigg(t - \frac{\ {\bf k} {\bf r}}{\omega} \bigg) \bigg]=\\=E_0 \exp \bigg[i\omega \bigg(t- \frac{k_{1x} x+k_{1y} y+k_{1z} z}{c} n \bigg) \bigg]}$$