Preparation of high-purity LiF, YF3, and YbF3for laser refrigeration

Hehlen, Markus P.; Boncher, William L.; Melgaard, Seth D.; Blair, Michael W.; Jackson, Robert A.; Littleford, Thomas E.; Love, Steven P.

Abstract

The role of transition-metal impurities in Yb3+-doped YLiF4 (YLF) laser-cooling crystals is studied. Divalent 3d transition-metal ions, in particular Fe2+, are found to have strong absorptions at the laser cooling pump wavelength and degrade the cooling efficiency by introducing background absorption. A set of eight substitutional and chargecompensated defects that form upon introduction of 1+, 2+, and 3+ transition-metal ions into the YLF crystal lattice is proposed. A calculation of solution energies for each defect type and for a range of 3d ions is carried out. It indicates that divalent 3d ions preferentially substitute for Y3+ accompanied by a fluoride vacancy for charge compensation. An electron paramagnetic resonance (EPR) study of a YLF crystal identifies Fe2+ in the crystal lattice, in agreement with the elemental analysis and the computational results. A strategy for purifying the YF3, LiF, and YbF3 starting materials for the YLF:Yb crystal growth is discussed. Chelate-assisted solvent extraction purification with pyrrolidine dithiocarbamate (APDC) for Y, Li, and Yb as well as ethylenediaminetetraacetic acid (EDTA) for Li was carried out.

Citation

Hehlen, M. P., Boncher, W. L., Melgaard, S. D., Blair, M. W., Jackson, R. A., Littleford, T. E., & Love, S. P. Preparation of high-purity LiF, YF3, and YbF3for laser refrigeration. Presented at SPIE OPTO, San Francisco, California, United States

• Presentation Conference Type: Conference Paper (published)
• Conference Name: SPIE OPTO
• Publication Date: Feb 19, 2014
• Deposit Date: Jun 16, 2023
• Journal: SPIE Proceedings; Laser Refrigeration of Solids VII
• Print ISSN: 0277-786X
• Electronic ISSN: 1996-756X
• Publisher: Society of Photo-optical Instrumentation Engineers
• Peer Reviewed: Peer Reviewed
• Series Title: Proceedings Volume 9000, Laser Refrigeration of Solids VII
• DOI: https://doi.org/10.1117/12.2039547
• Public URL: https://keele-repository.worktribe.com/output/471135