The photocells, when illuminated by a pulsed laser, provide power to the electronic circuits on the chip with ~10% efficiency. The chip transmits its ID through modulated current in the antenna. The varying magnetic field around the chip is received by a nearby coil in the reader, and the signal is digitized, analyzed, and decoded.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5896163/

So it’s security is that it’s not near field based but photovoltaic based. You’d have to copy it’s design to clone it.