I don't know of any wireless photo electric beam sensors that are compatible with any of the Elk wireless receivers. I suspect that one reason for this is that the beam requires some significant power, which doesn't work well with batteries.
If you are just trying to avoid running a wire back to the M1, but have a power source available for the beam, then you could use a wired beam sensor and connect it up to a Honeywell 5816, an Interlogix TX-E Series Door/Window Sensor, or an Elk 6022, all of which have auxiliary wired inputs to the wireless transmitter.