As the phase angle between the two electric vectors, ϕ, increases from zero, the ellipticity of the radiation increases and the principle axes of the ellipse rotate until they coincide with the...As the phase angle between the two electric vectors, ϕ, increases from zero, the ellipticity of the radiation increases and the principle axes of the ellipse rotate until they coincide with the co-ordinate axes at ϕ = π/2. The pulses from the various atoms are uncorrelated in phase; moreover, the dipole moments on the individual atoms are oriented at random and so the orientation of the electric vector of the emitted light is also oriented at random.