High power calibration of commercial power meters using an NIST-traceable secondary standard

For the past 19 years, the Laser Hardened Materials Evaluation Laboratory (LHMEL), located at Wright-Patterson AFB, OH, has maintained a number of calibrated high energy power measurement devices capable of measuring CO2 powers up to 150 kW. These devices, calibrated annually to the National Institute for Standards & Technology (NIST) high energy standard calorimeters, serve as secondary standards for in-house calibration of LHMEL's commercial power heads and calorimeters. Recent discussions with academic and industrial laser users have identified an industry need for traceable calibration sources above the 1 kW level. This paper describes the methods used to calibrate LHMEL's commercial power measurement devices using the LHMEL secondary standards and also describes the process by which other laser users can access these same calibration capabilities to confirm the accuracy of their own power heads and calorimeters. The LHMEL calibration capability offers academic and industrial laser users the opportunity to economically calibrate existing power measurement devices on demand to an NIST-traceable secondary standard. The method described has been applied to calibrate systems up to 100 kW while maintaining measurement accuracies to within +/-6.3%.