  It was demonstrated during the past decade that ultrashort intense laser
pulse tightly focused deep inside a transparent dielectric generates the energy
density in excess of several MJ/cm3. Such energy concentration with extremely
high heating and quenching rates leads to unusual solid-plasma-solid
transformation paths overcoming kinetic barriers to formation of previously
unknown high-pressure material phases, which are preserved in the surrounding
pristine crystal. These results were obtained with the pulse of Gaussian shape
in space and in time. Recently it was shown that the Bessel-shaped pulse could
transform much larger amount of a material and allegedly create even higher
energy density than that was achieved with the Gaussian (GB) pulses. Here we
present a succinct review of previous results and discuss the possible routes
for achieving higher energy density employing the Bessel beams (BB) and take
advantage of its unique properties.
