Examples of artificially grown crystals

calcium fluoride & calcium-stroncium fluoride 

From left to right: boules: 1 - pure SrF2; 2 - pure CaF2; 3 - Ca0.1Sr0.9F2; 4 - 1.8%(YbF3),2.5%(NaF):Ca0.66.6Sr33.3F2 5 - 1.8%(YbF3),2.5%(NaF):CaF2 optical windows: on left - 1.8%(YbF3),2.5%(NaF):CaF2; on right - 1.8%(YbF3),2.5%(NaF):Ca0.66.6Sr33.3F2
[Contributed by Powered by: Svilen M. Gechev & Jordan T. Mouhovski on 27 Jun 2014]          

Crystal details

Compound name calcium fluoride & calcium-stroncium fluoride
Formula CaF2 & CaSrF2
Dimensions (26.4 x 27.5 +- 1); (boule №:3 32.65 x 17.65) ; (optical windows 2.54 x 2.9)
Mass ≈30 g each
Colour transparent
Keywords inorg; bulk

Growth conditions

Technique Modified Bridgman-Stockbarger Method
Temperature Upper zone - 1537/ down zone - 1073
Pressure 3 mbar
Growth rate
Solvent YbF3 & NaF
Doping procedure YbF3 & NaF
Keywords melt; vapour; sol; solid


Application(s) It is all about the novel generation femtosecond quantum amplifiers; DUV and VUV microlithography optics [Mouhovski 2013]. The Alkaline-Earth Elements (AEE) fluoride crystals are attractive for cutting-edge optical applications. Among them, CaF2 gains advantage because of the lower light dispersion, radiation hardness and favorable luminescence peculiarities [Mouhovski 2013, Gechev et all. 2013]. Doped/codoped the optical fluorides are promising as lasant materials because of their lasing properties for nonlinear optics or improved short-pulse laser generative applications with potential for high impact on medicine, automotive industry, ICT etc. [Mouhovski 2013, Druon et all. 2011, Gechev et all. 2013]
Link(s) http://www.baspress.com/book.php?l=b&id=1023; http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=05772684; http://www.bgd.bg/CONFERENCES/Geonauki_2013/Sbornik/pdf/05_Gechev_GeoSci_2013.pdf
Other remarks The optical fluorides doped/codoped with Rare-Earths or Transition Metals, they posses fairly good thermal characteristics quite not tipical for high ordered crystal structures [Druon et all. 2011]. Appropriately pumped by laser diodes or other source they emit with reasonable wide emission spectra during long emission lifetime [Mouhovski 2013]. In the fluoride lattice Yb3+ ions have simple structure of the electron levels which reduces the quantum defects in the system and results in emitting laser pulses with high efficiency and great repetition.

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