$f$ and $g$ are specified, so that the right hands of (\[c32\]) and (\[c37\]) become identical to the electric and magnetic susceptibility tensors of the medium, then according to the constitutive equations (\[c31\]) and (\[c36\]) the operators $\underline{\vec{P}}$ and $\underline{\vec{M}}$ defined by (\[c13\]) and (\[c13.1\]) are respectively the polarization and magnetization of the medium.\
There are media for which the polarization ( the magnetization) is dependent on both the electric and magnetic field. This quantization scheme can be generalized for such media if in the interaction Lagrangian (\[c4\]) each of the dynamical variables $\vec{X}_\omega$ and $\vec{Y}_\omega$ is interacted with both the electric and magnetic field.\

 Space -time dependence of the electromagnetic field operators
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Our goal for this section is to determine the complete expressions of the electromagnetic field operators for both negative and positive times. The Heisenberg equations of the total system, that is the Maxwell equation (\[c27.1\]) together with the constitutive equations (\[c27\]), (\[c31\]) and (\[c36\]), constitute a set of coupled linear equations which can be solved in terms of the initial conditions by the temporal Laplace transformation. This technique has been used previously in the damped polarization model[@19]. For an arbitrary time-dependent operator $\Gamma(t)$ the backward and 