Thermal behavior characterization of a kilowatt-power-level cryogenically cooled Yb:YAG active mirror laser amplifier

Han Chi, Cory M. Baumgarten, Elzbieta Jankowska, Kristian A. Dehne, Gabe Murray, Alexander R. Meadows, Mark Berrill, Brendan A. Reagan, Jorge J. Rocca

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

We present an analysis of the thermal behavior of a high-energy kilowatt-average-power diode-pumped cryogenically cooled Yb:YAG active mirror laser amplifier based on measurements and simulations. Maps of the temperature distribution of the laser material at pump powers up to 1 kW were obtained for the first time by spatially and spectrally resolving the fluorescence induced by a scanning probe beam. The wavefront distortion resulting from the front surface deformation and the overall deformation of the gain medium assembly were measured using a Mach–Zehnder interferometer. The measured deformations agree well with the results of thermomechanical modeling using finite element method simulations, and with the results of focal length shift measurements. The relative contributions to the optical path difference (OPD) of the mechanical deformations, refractive index changes, and electronic contribution are discussed. We show that the Cr 4 :YAG cladding plays a significant role in both the temperature distribution and the overall OPD changes. The pump-induced mechanical deformations of the assembly dominate the OPD changes in this kilowatt-average-pump-power cryogenically cooled Yb:YAG active mirror laser.

Original languageEnglish
Pages (from-to)1084-1090
Number of pages7
JournalJournal of the Optical Society of America B: Optical Physics
Volume36
Issue number4
DOIs
StatePublished - Apr 1 2019

Funding

U.S. Department of Energy (DOE) Accelerator Stewardship program (DE-SC0016136). The authors acknowledge the contributions from and helpful discussion with Hanchen Wang and Liang Yin.

FundersFunder number
U.S. Department of EnergyDE-SC0016136

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