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SYNOPSIS: BOSE-EINSTEIN CONDENSATES FOR GAMMA-RAY LASERS
Physics
July 10 2014
Hamlet Avetissian/Yerevan State University
Self-Amplified Gamma-Ray Laser on Positronium Atoms from a
Bose-Einstein Condensate
H.â~@~IK. Avetissian, A.â~@~IK. Avetissian, and G.â~@~IF. Mkrtchian
Phys. Rev. Lett. 113, 023904 (2014) Published July 10, 2014
Gamma-ray lasers could have a number of important applications,
from high-resolution imaging to new ways to probe or control nuclear
transitions. But building such lasers is still impossible because
of the lack of suitable amplification media and mirrors. As reported
in Physical Review Letters, Hamlet Avetissian and colleagues at the
Yerevan State University in Armenia have theoretically investigated
a gamma-ray laser based on a Bose-Einstein condensate (BEC) of
positronium--hydrogenlike atoms made of an electron and a positron.
Their analysis suggests that such a laser could be easier to build than
previously thought, since it could be based on a single-pass scheme
that does not rely on gamma-ray mirrors. Although physicists have yet
to make a positronium BEC, recent advances in the manipulation of the
short-lived particles suggest the authors' theory might soon be tested.
In the positronium-BEC laser, first theorized at Bell Labs in 1993,
annihilations of electron-positron pairs are stimulated by photons
of the same energy ( mega-electron-volts); annihilation thus plays
the role of electronic transitions in a regular laser. Previous
theoretical papers have investigated classical laser schemes, with
the BEC gain medium placed between two mirrors. But the new work
of Avetissian and colleagues shows that a simpler scheme could be
possible: under certain parameter combinations, a very efficient
cascade of annihilations, triggered by spontaneous emission, could
determine lasing in one pass. This efficient process is enabled by an
instability arising thanks to the simultaneous coherence of the BEC
and the photon beam. The authors suggest that such "double coherence"
may be exploited as a general lasing mechanism for BECs based on
other atoms or quasiparticles. -- Matteo Rini
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.113.023904
Physics
July 10 2014
Hamlet Avetissian/Yerevan State University
Self-Amplified Gamma-Ray Laser on Positronium Atoms from a
Bose-Einstein Condensate
H.â~@~IK. Avetissian, A.â~@~IK. Avetissian, and G.â~@~IF. Mkrtchian
Phys. Rev. Lett. 113, 023904 (2014) Published July 10, 2014
Gamma-ray lasers could have a number of important applications,
from high-resolution imaging to new ways to probe or control nuclear
transitions. But building such lasers is still impossible because
of the lack of suitable amplification media and mirrors. As reported
in Physical Review Letters, Hamlet Avetissian and colleagues at the
Yerevan State University in Armenia have theoretically investigated
a gamma-ray laser based on a Bose-Einstein condensate (BEC) of
positronium--hydrogenlike atoms made of an electron and a positron.
Their analysis suggests that such a laser could be easier to build than
previously thought, since it could be based on a single-pass scheme
that does not rely on gamma-ray mirrors. Although physicists have yet
to make a positronium BEC, recent advances in the manipulation of the
short-lived particles suggest the authors' theory might soon be tested.
In the positronium-BEC laser, first theorized at Bell Labs in 1993,
annihilations of electron-positron pairs are stimulated by photons
of the same energy ( mega-electron-volts); annihilation thus plays
the role of electronic transitions in a regular laser. Previous
theoretical papers have investigated classical laser schemes, with
the BEC gain medium placed between two mirrors. But the new work
of Avetissian and colleagues shows that a simpler scheme could be
possible: under certain parameter combinations, a very efficient
cascade of annihilations, triggered by spontaneous emission, could
determine lasing in one pass. This efficient process is enabled by an
instability arising thanks to the simultaneous coherence of the BEC
and the photon beam. The authors suggest that such "double coherence"
may be exploited as a general lasing mechanism for BECs based on
other atoms or quasiparticles. -- Matteo Rini
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.113.023904