Work

Twenty kilowatts level high beam quality spectral beam combination by dual gratings with distinct groove densities based on conical diffraction structures

Year: 2024

Type: article

Abstract: We establish a spectral beam combing structure with two distinct diffraction gratings. A theoretical analysis of the beam quality degradation of this beam combining system is given. A six-channel spectral beam combining experiment is constructed based on conical diffraction structure by transmission and reflection gratings. Over 19 kW combined power is achieved with a combining efficiency of about 92%. The six incident fiber amplifiers, ranging from 1040 nm to 1082 nm, can each deliver a 3.5 kW output power laser with about 60 GHz 3 dB linewidth. Both transmission and reflection diffraction gratings, with different grating periods (1000lines/mm, 1170lines/mm), are employed in this work. The combined beam quality factor is controlled to be M 2 ∼2 by effective dispersion compensation. To the best of our knowledge, this is the first time to demonstrate a high power beam combination by two gratings with different types and periods, which verifies the dispersion capability of this structure and provides an alternative approach for high power beam combining.

Source: Optics Express

DOI: 10.1364/oe.541011