High amplification laser-pressure optic enables ultra-low uncertainty measurements at kilowatts

TL;DR

This paper demonstrates a novel optical system that amplifies laser pressure to measure kilowatt laser power with less than 1% uncertainty, significantly advancing precision in laser power metrology.

Contribution

It introduces a multiple reflection optical system that enhances radiation pressure measurements, achieving unprecedented accuracy in high-power laser calibration.

Findings

Achieved sub-1% uncertainty in kilowatt laser power measurement.

Demonstrated a fourfold improvement in measurement precision over previous methods.

Validated the method's traceability to the SI kilogram.

Abstract

We present the first measurements of kilowatt laser power with an uncertainty less than 1 %. These represent progress toward the most accurate measurements of laser power above 1 kW at 1070 nm wavelength and establish a more precise link between force metrology and laser power metrology. Radiation pressure, or photon momentum, is a relatively new method of non-destructively measuring laser power. We demonstrate how a multiple reflection optical system amplifies the pressure of a kilowatt class laser incoherently to improve the signal to noise ratio in a radiation pressure-based measurement. With 14 incoherent reflections of the laser, we measure a total uncertainty of 0.26 % for an input power of 10 kW and 0.46 % for an input power of 1 kW at the 95 % confidence level. These measurements of absolute power are traceable to the SI kilogram and mark a state-of-the-art improvement in measurement precision by a factor of four.