  We present new developments of the laser-induced transient grating
spectroscopy (TGS) technique that enable the measurement of large area 2D maps
of thermal diffusivity and surface acoustic wave speed. Additional capabilities
include targeted measurements and the ability to accommodate samples with
increased surface roughness. These new capabilities are demonstrated by
recording large TGS maps of deuterium implanted tungsten, linear friction
welded aerospace alloys and high entropy alloys with a range of grain sizes.
The results illustrate the ability to view grain microstructure in elastically
anisotropic samples, and to detect anomalies in samples, for example due to
irradiation and previous measurements. They also point to the possibility of
using TGS to quantify grain size at the surface of polycrystalline materials.
