MORE ON ATOMS
In fluorescence, an atom emits photons
of different (lower) frequency than the ones absorbed. In
phosphorescence, this emission is delayed for a long period of
time, seconds or minutes or hours.
Hint... two photons are
absorbed for each one that's emitted.
Green laser pointers use Diode
Pumped Solid State Frequency Doubling technology. They begin
with a high power infrared laser diode that generates light at
808nm, which pumps a crystal of Nd:YVO4 (Neodymium-doped Yttrium
OrthoVanadate). That crystal generates light via stimulated
emission, at 1064 nm, which feeds a KTP (Potassium Titanyl
Phosphate, KTiOPO4) intracavity frequency doubler, which
produces a green beam at 532 nm. The green beam then travels
thru an output coupler, an expanding lens, an IR filter to
remove unwanted IR from the beam, then thru a collimating lens
and finally exits thru a glass output window. The IR filter is
needed to elminate the intense infrared light that gets through
the system, which is dangerous since it is invisible to the eye.
The green beam itself is also very, very dangerous to the eye.
AN X-RAY LASER!
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