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Journal of Materials Science and Nanotechnology | Volume: 2
August 20-21, 2018 | Paris, France
Materials Science and Materials Chemistry
International Conference on
Solid state chemistry of Ca and Cr in the processing of Cr
4+
:YAG laser ceramics
Oleh Vovk
and
Mykhailo Chaika
National Academy of Sciences, Ukraine
L
asers based on Nd:YAG are widely used in military,
materials processing, medicine etc. These lasers consist
on active element Nd:YAG and Q-switcher Cr
4+
:YAG. A recent
trend in manufacturing of such elements is replacing single
crystals with ceramics of high optical quality. The innovation
approach to manufacture the laser can be developed, when
both elements made from ceramics. In this case, a combined
block of the active element andQ-switcher (Nd:YAG-Cr
4+
:YAG)
can be obtained in one technological route that allows
both decreasing laser size and avoiding several expensive
technological stages. To realize this approach a harmonization
of the sintering routes of both types of ceramics should
be carried out. Up today the huge progress has achieved
in the sintering of Nd:YAG ceramics of high optical quality
while the production of the Cr
4+
:YAG still remains more
art than technology. To reveal the possibility of adjusting
the sintering routes of Nd:YAG and Cr
4+
:YAG ceramics, the
solid state chemistry of the Ca and Cr ions that are used
as main additives to produce Cr
4+
:YAG ceramics has been
investigated. The effect of Cr ion on the formation of Cr
4+
:YAG
ceramics has been investigated and was revealed that Cr ions
enhanced the optical properties of the final ceramics due
to the appearance of the intermediate, which lowering the
rates of solid state reactions under sintering. The dual role
of Ca as sintering and charge compensator for Cr
4+
has been
studied and optimal Ca concentration was determined. The
kinetics of Cr
3+
oxidation to the Cr
4+
under air annealing has
been investigated to maximize the Cr
4+
amount in ceramics
Cr:YAG. The significant difference between the ceramics
and single crystal has been revealed. It was established
that the limitation stage of Cr oxidation is oxygen diffusion
in ceramics grains. The results obtained allow designing the
combined sintering route of Nd:YAG and Cr
4+
:YAG ceramics.
e:
oleh.vovk@isc.kharkov.ua