Page 21 - 00. Complete Version - Progress Report IPEN 2014-2016

Lasers Technology | Progress Report 21

lows for effectively focusing around corners gle crystal fibers can be grown up to limited
through multiple scattering samples. Yb concentrations. Single crystal fibers with
1 mm in diameter and 10mm long were pre-
In order to obtain these lasers(,) the growth of pared with fixed Er concentration (0.5 mol%)
crystal is an important acitivity (activity) in and 1, 2, 5, 7 and 10 mol% of Yb.
our center(.) Single crystal fibers are known
as a low cost and reduced dimension alterna- Because of the suitable optical properties of al-
tive for laser devices and an ideal method for kaline-earth fluorides - CaF2, SrF2, BaF2, MgF2,
crystallization studies. Fiber crystals are also MnF2, this family of crystals, in particular the
particularly well suited for wave-guiding in CaF2, are (is) commonly used to build com-
the IR region, tunable narrow-band filters and mercial optics and devices in the ultraviolet as
nonlinear optics due to their long interaction well as in the infrared spectral domain. They
length and tight beam confinement. (also) found application also as laser hosts. The
growth of BaF2 single crystal fibers, doped with
Rare earth doped tungstate single crystals have rare earth ions (Pr3+, Tm3+) for spectroscopic
early gained attention because of their suit- studies aiming (to) the development of com-
able properties for la-
ser media application.
However, many of the
tungstate compounds
undergo phase transi-
tions and they cannot
be grown directly from
their melts. Among
the tungstate crys-
tals(,) the compound
LiLa(WO4)2 is one that
have (has) a relative-
ly low melting point
(1065 ºC) and no phase
transitions upon cool-
ing. We investigated
the growth process of
Er3+/Yb3+:LiLa(WO4)2
single crystal fibers
by the micro-pulling
down method. The
material’s synthesis
Fig 3 - Single crystal fibers grown by micro-pulling down method
by solid-state reaction
and the effect of dif-
ferent dopant concentrations on the melting pact laser systems(,) were (was) performed. The
properties were studied. (The) Addition of Yb equilibrium of thermal conditions for the pull-
modify (modifies) the melting behavior of this ing of regular and homogeneous BaF2 single
compound and LiLa(1-x)Yb(x)(WO4)2 sin- crystal fibers were (was) defined for the mi-