Use of radiation pressure for measurement of high-power laser emission.

We demonstrate a paradigm in absolute laser radiometry where a laser beam's power can be measured from its radiation pressure. Using an off-the-shelf high-accuracy mass scale, a 530 W Yb-doped fiber laser, and a 92 kW CO(2) laser, we present preliminary results of absolute optical power measurements with inaccuracies of better than 7% to 13%. We find negligible contribution from radiometric (thermal) forces. We also identify this scale's dynamic-force noise floor for a 0.1 Hz modulation frequency as 4 µN/Hz(1/2) or, as optical power sensitivity, 600 W/Hz(1/2).