You can move a watt per cm^2 with a single-stage Peltier effect device, depending on the temperature difference you need. Here's a data sheet for a 9mm by 9mm device that can do 1W/cm^2 at 40C temp difference:

https://cdn2.hubspot.net/hubfs/547732/Data_Sheets/NL1012T.pd...

The OP claims 1000 W/m^2 theoretical max for the optical cooler. That's 0.1W/cm^2. Right now they say it's 0.6% of that theoretical max.