An absolute laser power meter based on the momentum ex-changed between the incident beam and a movable mirror is described. The force exerted by the beam on the mirror is proportional to the incident power. Thus, from the measurement of the force value, we can deduce the incident power carried by the beam. But, generally speaking, the coefficient linking the exerted force and the incident power contains parameters which cannot be known with precision. The conceived device we describe cancels these parameters.
"Absolute Measurement Of Laser Beam Energy Using Its Radiation Pressure Force," Optical Engineering 20(3), 203437 (1 June 1981). https://doi.org/10.1117/12.7972737