Yes, a photon can be split, or more precisely, it can undergo a process called photon splitting. Photon splitting refers to the phenomenon where a high-energy photon spontaneously splits into two lower-energy photons. However, it's important to note that this process is extremely rare and typically occurs under very specific conditions.
Photon splitting is a prediction of certain extensions to the Standard Model of particle physics, such as some versions of quantum gravity theories or certain models involving hypothetical particles called axions. In these theories, the high-energy photon interacts with the virtual particles of the quantum vacuum, resulting in the production of two lower-energy photons.
Experimental evidence for photon splitting has not been observed so far, and it remains a topic of theoretical investigation and ongoing scientific research. If confirmed, it would have important implications for our understanding of fundamental physics and the behavior of light at very high energies.