  Identified is a set of ballpark parameters for laser, plasma, and accelerator
technologies that are defined for accelerated electron energies reaching as
high as PeV. These parameters are carved out from the scaling laws that govern
the physics of laser acceleration, theoretically suggested and experimentally
explored over a wide range in the recent years. We extrapolate this knowledge
toward PeV energies. In the density regime on the order of 10^16 cm^-3, it is
possible to consider the application of the existing NIF (or LMJ) or its
extended lasers to their appropriate retrofitting for this purpose. Although
the ambition of luminosity is not pursued, such energies by themselves may
allow us to begin to feel and study the physics of the 'texture of vacuum'.
This is an example of fundamental physics exploration without the need of
luminosity paradigm. By converting accelerated electrons with extreme energies
to like energy gamma photons, and let them propagate through vacuum over a
sufficient distance, these extremely high energy (and therefore short
wavelength) photons experience smallest vacuum structures and fluctuations. If
we can measure the arrival time differential and thus the gamma photon speed as
a function of different energies such as 0.1 PeV vs 1 PeV, say within
attoseconds accuracy, we can collect valuable data if and how gamma photons
still obeys the premise of relativity or the vacuum texture begins to alter
such fundamentals. The only method currently available to look at this problem
may be to study astrophysical data of the primordial gamma ray bursts (GRBs),
which are compared with the presently suggested approach.
