A radiation pressure apparatus for high-accuracy laser power measurement at tens of kilowatt level

With the rapid development of high-power laser systems in national defence and industrial manufacturing, the accurate metering of laser power has become a crucial issue. Compared with the traditional photoelectric attenuation sampling method and absorption heat transfer method, radiation pressure measurement provides a new idea for the accurate, fast and online measurement of high laser power. In this paper, we built a radiation pressure measurement(PRM) apparatus for high-accuracy laser power measurement at tens of kilowatt levels based on the commercial electronic scale. Based on this apparatus, serial experiments are carried out under different output conditions. The experiments show that the signal showed a significant downward trend and the degree of decline was positively correlated with the power and the output duration. By analyzing the laser heating process of the high mirror and the corresponding changes of the air around, we find that the air density on the surface of the sensor mirror is less than that on the lower surface, which results in the buoyancy of the air in the upward direction. Therefore, a compensation strategy for the laser pressure signal is proposed, which can revise the light pressure signal effectively. Moreover, the apparatus is used to measure the power of the CW laser, with a wavelength of 1070nm and power ranging from 1kW to 16kW, compared with the calibrated heat-exchange energy meter in real time. The power values obtained by the PRM and heat-exchange energy meter show excellent consistency, with a linearity of 99.994%. The above research proves that the radiation pressure measurement technology can effectively meter the power at tens of kilowatt level, and is also expected to replace calorimetry as the standard device in the tens of kilowatt range.