Multidisciplinary Approaches to Radiation Balanced Lasers (MARBLe): 1st Annual Progress Report

Technical Report · Tue Sep 12 00:00:00 EDT 2017

DOI:https://doi.org/10.2172/1392826· OSTI ID:1392826

Hehlen, Markus Peter ^[1]

---

1. Los Alamos National Lab. (LANL) and New Mexico Consortium (NMC), Los Alamos, NM (United States)

The initial main modifications of the existing μPD crystal-growth system at LANL have been completed. This now gives us the new capability to develop the growth of crystalline RBL materials by both the μPD and the Bridgman method. Quantitative mass spectrometry of the growth atmosphere was conducted to identify possible sources of gaseous trace species (primarily hydrogen) that could cause the undesired reduction of Yb³⁺ to Yb²⁺ during the crystal growth. Hydrogen was found to be at sufficiently low levels to not be a respective concern. Studies on the thermal decomposition of YbF₃ to form Yb²⁺ are currently underway in collaboration with MARBLe team member Prof. Pauzauskie. First samples of Yb³⁺-doped YLiF₄ (YLF:Yb) and undoped LiLuF₄ (LLF) were grown, and MARBLe team member Prof. Sheik-Bahae has performed measurements of laser-induced heating (YLF:Yb) and background absorption coefficient (LLF). We discovered that one or several of the YF₃, LiF, and YbF₃ precursors contains organic impurities that chemically reduce to black residue during the high-temperature growth in oxygen-free argon atmosphere. A process for removal of these residues prior to growth is being considered. Comparing the results from incongruently melting YLF with those of congruently melting LLF indicate that a congruently melting material is preferred for Bridgman growth. Crystal-growth experiments with LLF are currently underway. The results of these studies on Yb³⁺ doped materials will be directly applicable to the future growth of Er³⁺ and Tm³⁺ doped as well as Yb³⁺, Nd³⁺ co-doped RBL crystals. There was no activity on the parallel effort of developing rareearth- doped chalcogenide glasses. The primary reason was a lack of manpower due to a delayed hiring of a student. In September 2017, we have hired a Postdoctoral Researcher who will be able to contribute to the growth (at LANL) and optical characterization (at UNM) of RBL materials.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 1392826
• Report Number(s): LA-UR-17-28195
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Material Science