It is known that lasers are based on
various media: on ruby crystals, on inert gases (Helium & Neon), on CO_2 etc.
In Reagan's projects of Star Wars in the middle of 1980s the laser based on
a nuclear explosion was discussed. Following this idea, one can expect to
use the Sun as an active medium for a laser. Two satellites at diametrically
opposite positions on a circular Solar orbit can carry two mirrors composing
The Sun can de understood as a completely ionized gas. Therefore orbital
electronic transitions cannot be used for such a laser. However, there are
quantum states of nuclei. Transitions between these quantum states possibly
can produce a coherent radiation of the "gluon field". Why not ? This is
the question for specialists.
See the descussion of this project in