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Miniature Force Sensor for Absolute Laser Power Measurements via Photon Momentum at Hundreds of Watts



Alexandra B. Artusio-Glimpse, Natalia A. Azarova, Paul A. Williams, Joshua A. Hadler, John H. Lehman, Ivan Ryger


We present a small power meter that detects radiation pressure of the incident high-power laser. Given its small package and non-destructive interaction with the laser, this power meter is an approach to realizing robust real- time, high-accuracy power measurement in laser-based manufacturing environments. With a 20 mm diameter high reflectivity mirror at the center of a dual element spiral flexure and interferometric detection of flexure position, this device can measure laser power from 25 W to 400 W with a 260 mW/sqrt(Hz) noise floor and <3.2 % expanded uncertainty. We validate our device against a calibrated thermopile with simultaneous measurements of an unpolarized 1070 nm laser and report good agreement between the two systems. Finally, by referencing to an identical mechanical spring that does not see the incident laser, we suppress vibration noise in the power measurement by 14.8 dB over a 600 Hz measured bandwidth, an improvement over other radiation pressure based power meters that have previously been demonstrated.
Optics Express


radiometry, radiation pressure, photon momentum, photon pressure, force metrology, optical power, high power laser, portable, compact, laser metrology
Created April 20, 2020, Updated July 2, 2020