They can't. An RF antenna for useful wavelengths is much bigger than the size of the proteins you can genetically engineer. We CAN engineer proteins sensitive

They can't. An RF antenna for useful wavelengths is much bigger than the size of the proteins you can genetically engineer. We CAN engineer proteins sensitive to light (eg: use the ones that are already present in your retina, and connect them to an ion channel typically found in a neuron). What you're proposing is not simple (though WOULD be immensely helpful for neuroscience research...)