Dark energy

Clearly dark energy is something that does not interact with anything but gravitation. Could it be that it is actually extremely high-frequency electromagnetic (EM) radiation?
The idea behind this suggestion is that at of high enough frequency, matter becomes transparent to EM radiation due to that the particle resonators (atoms in the case of crystals) no longer have any overlap with with the wave function of the EM radiation. This is a well known phenomenon for e.g. gamma radiation, or even UV, where the penetration depth increases with increasing frequency.
If we assume a T4-law of the radiation at Big Bang (BB), what temperature must it have been to generate 98% of the Universe energy at frequencies above interaction with the matter as we know it?

Taking this one step further, if the radiation frequency distribution at BB was some kind clock shape, there seem to be a division at different spectral lines which do not interact with each other since we are now in a situation where all radiation above this frequency is effectively non-interacting with the rest of the Universe. Except via gravitation.

Thus we need some gravitational process that is non-linear or lossy in its interaction with the high-frequency EM radiation to make a high-frequency photon decay into something with lower energy (frequency) to make it visible.