An ion
laser is a gas
discharge laser.
It
consists of a
plasma tube filled with either
argon or
krypton or a
mix of the two. At one end of the
tube is a
normal mirror while in the other is
a semitransparent
mirror(this
mirror only
lets some of the
light with the
laser's
emission
frequency, through). The drive current(about 100 V up to 10A) is applied
to
electrodes in the tube(the
cathode is a
filament
that needs an
additional 3 V 20 A 'glow'
current).
To start the tube a starting
pulse of over 10 kV is applied. This starts an
ionizing process
that emits
photons, some of these
photons
bounce between the
mirrors, the rest(having an
undesired angle) will
exit through or be
absorbed by the
tube's
walls. The
bouncing photons
stimulate
further
emission of
photons with the same
direction,
wave frequency and
phase. This
light will eventually
exit through the
semi transparent mirror and
form the
laser beam.
The
argon ion laser and
krypton ion laser is
similar in function to the
HeNe laser
but has higher
output effect, usually from 10 mW to several 100's of
mW(but much more powerful ion lasers exist). The
ion lasers
most commonly found in
high speed printing
machines(for commercial
printing) and
surgery.