MIR

The Schwinger radiation is predicted to occur through the interaction of the vacuum virtual photons with a moving mirror subject to a non-constant acceleration.

The effect is so tiny that the only hope to observe the radiation is to employ a resonant electromagnetic cavity rather than a single mirror, since in this case the number of produced photons is multiplied by the Q–factor of the cavity.

The experimental difficulty is represented by the requirement of having one of the cavity walls vibrating at twice the proper e.m. frequency of the cavity ( typically 109 Hz).

Mechanically this does not seem feasible.

This experiment investigates the possibility of producing a “vanishing wall”, which would mimick a real moving wall. This may be possible utilizing the properties of a semiconductor illuminated by the light of a laser: when the s.c. is not illuminated it is transparent to the radiofrequency, but if it is suddenly illuminated, electrons are promoted to the conduction band and the material becomes a sort of metal, hence a mirror.

If this on-off switching can be accomplished at the required frequency, a moving mirror situation can be realized.