What is the explicit expression of a plane wave in the frequency domain?

A plane wave in the time domain can be written (using notation for an electric field):

$\mathit{E}(\mathit{r},t)={\mathit{E}}_{0}{e}^{i(\mathit{k}\mathit{r}-\omega t)}$

what is the corresponding expression for a plane wave, $\mathit{E}(\mathit{r},\omega )$, in the frequency domain?

A plane wave in the time domain can be written (using notation for an electric field):

$\mathit{E}(\mathit{r},t)={\mathit{E}}_{0}{e}^{i(\mathit{k}\mathit{r}-\omega t)}$

what is the corresponding expression for a plane wave, $\mathit{E}(\mathit{r},\omega )$, in the frequency domain?