Optical properties of transparent polycrystalline ruby (Cr:Al2O3) fabricated by high-pressure spark plasma sintering

Barak Ratzker, Avital Wagner, Bar Favelukis, Sharone Goldring, Sergey Kalabukhov, Nachum Frage

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Doped transparent ceramics with high optical quality can serve as materials for photonic applications such as laser gain media. In that regard, transparent polycrystalline alumina has potential for high-power applications due to its excellent physical and chemical properties, combined with unique doping possibilities. However, optical birefringence of Al2O3 crystals make achieving sufficiently high optical transmittance a processing challenge. In the present study, we demonstrated fabrication of highly transparent 0.5 at.% Cr:Al2O3 ceramics by high-pressure spark plasma sintering (HPSPS). The optical properties of these polycrystalline ruby ceramics were analyzed in order to assess possible laser operation (at 694.3 nm). The obtained ceramics exhibit high in-line transmittance (∼72.5 % at 700 nm), equivalent to a scattering coefficient of 2.15 cm−1, and characteristic ruby photoluminescence. The theoretically estimated lasing threshold and percentage of absorbed pump power indicate that such ruby ceramic lasers could operate at reasonable thresholds of 80−225 mW with short lengths of 0.5−5 mm. Thus, HPSPS is a promising method for producing laser-quality doped transparent ceramics for compact laser systems.

Original languageEnglish
Pages (from-to)3520-3526
Number of pages7
JournalJournal of the European Ceramic Society
Volume41
Issue number6
DOIs
StatePublished - 1 Jun 2021

Keywords

  • Absorption cross section
  • Cr-doped alumina
  • Laser gain medium
  • Laser threshold
  • Transparent ceramic

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