A rubidium atom travelling at the speed of sound absorbs photons from an oncoming laser
beam. Each photon can be viewed as a tiny ping pong ball having momentum 7.79 x 10-28
Nt/sec. The atom absorbs a photon which is then reradiated in any direction. Hence, on
average each photon absorption/reemission reduces the atom’s momentum by a photon
momentum.
b) What is the deceleration experienced by the atom if it can absorb and reradiate a photon
every 2.5 x 10-8 sec?
c) What distance does it take to stop an atom?
d) How many photons/sec are required to stop a beam of 109 atoms/sec?
thank you
beam. Each photon can be viewed as a tiny ping pong ball having momentum 7.79 x 10-28
Nt/sec. The atom absorbs a photon which is then reradiated in any direction. Hence, on
average each photon absorption/reemission reduces the atom’s momentum by a photon
momentum.
b) What is the deceleration experienced by the atom if it can absorb and reradiate a photon
every 2.5 x 10-8 sec?
c) What distance does it take to stop an atom?
d) How many photons/sec are required to stop a beam of 109 atoms/sec?
thank you