Radiation-Pressure Enabled Traceable Laser Sources at High CW Powers

Abstract

Radiation pressure has recently been shown to have practical application for multi-kilowatt CW laser power measurement. One key advantage lies in its ability to measure without absorbing the laser beam. This enables a new measurement paradigm where laser power can be measured traceable to the SI without perturbing the beam. Combining this measurement scheme with a laser constitutes a “traceable source” where laser output power is traceable to the SI in real time. This greatly simplifies the calibration process for multi-kilowatt laser power meters and yields a path to high-accuracy laser-based material processing. Here, we discuss the state of the art of this approach by describing recent results from calibrations of laser power meters performed using a radiation-pressure-enabled traceable source at CW powers from 1 kW to 50 kW. We describe measurement results and uncertainty contributions with expanded uncertainties at or below 1.7 % for powers above 10 kW. We also briefly discuss the status of development of a radiation-pressure based technology designed to provide source traceability in the laser manufacturing environment.