elementary particles - Can you split a photon?

I was wondering if a photon is divisible.

If you look at a photon as a particle, then you may be able to split it (in theory).

Is it possible and how do you split it?

Answer

The photon cannot be split as one can split a nucleus. As it has zero mass it cannot decay. But it can interact with another particle lose part of its energy and thus change wavelength. It can be transmuted.

Have a look at the compton scattering entry in wikipedia.

Edit: Intrigued by the other answers I searched and found that within special crystals "splits" can happen, if one defines as a split that there can come out two photons whose energy adds up to the original energy of the photon. So in a collective crystal photon interaction there exists such a probability.