Just a point of clarification, for a CO2 laser, getting 150 optical watts out the aperture usually means putting about 1500 electrical watts into the tube. The

Just a point of clarification, for a CO2 laser, getting 150 optical watts out the aperture usually means putting about 1500 electrical watts into the tube. The rest comes out as heat in the water jacket, which you pass through a radiator or possibly an active chiller, and those pumps and fans draw their own power as well. And before those 1500W get into the tube, they go through a high-voltage power supply, which is maybe 80% efficient if you're lucky. All-up power draw on a laser of that scale is somewhere north of 2KW from the wall. (And before anyone asks: Yes this is very good efficiency for a laser, which is one reason why CO2 is so popular. YAG and fiber lasers tend to be in the low single-digit percents.)