“The team recorded more than 800 watts of power delivered during a 30-second transmission from a laser 8.6 kilometers (5.3 miles) away.”
DARPA beamed more than 800 watts over 8.6 km for 30 seconds. Efficiency was a bit over 20% and only at shorter range, and the team says it was not the focus. The customer is the battlefield. They also made popcorn with it.