  We report on single crystal growth of laser material Nd:YAG widely used in
the applications by innovative crucible-free floating zone method implemented
in an advanced laser optical furnace. We have optimized the parameters for the
production of high-quality single crystals of the size typical for laser tubes.
To reduce the strain and improve machinability, we have developed an
afterheater to thermalize the grown part of a single crystal below the hot
zone, which is a technique unavailable in common mirror furnaces. The high
quality of the single crystals was verified by Laue diffraction and the
internal strain was documented by neutron diffraction. The absorption spectrum
corresponds with the parameters of the commercially used material produced by
Czochralski method. The presented methodology for the single crystal growth by
floating zone method with laser heating is applicable for the preparation of
other high-quality single crystals of oxide-based materials, particularly in an
oxidizing environment unattainable in commonly used crucible methods.
