Game Development Reference
In-Depth Information
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Figure 14-6.
Inside a laser, photon emissions can stimulate additional photon emissions.
The energy of the emitted photons will depend on the difference in energy between the
upper and lower energy states that the electron transitions. The energy levels themselves will
depend on the material that makes up the lasing medium. Different lasing mediums will generate
photons of different energy levels and wavelengths.
To generate a laser beam, two mirrors are placed on either end of the lasing medium. The
laser is then pumped to create a large number of atoms in one of the excited energy states. When
the atoms begin to transition from their excited state, the photons bounce back and forth between
the mirrors, causing more and more of the atoms in the same excited state to transition and
generate photons. One of the mirrors is only partially reflective, allowing some of the laser light
to pass through.
Figure 14-7 shows a typical helium-neon laser. The laser is pumped using an electrical
discharge inside the brightly glowing tube. The laser beam is the thin beam emanating from
the left end of the device. Normally the laser beam itself would not be visible unless there were
dust, mist, or some other particles in the air to reflect the light.
Figure 14-7.
A typical helium-neon laser (Photo courtesy of Meredith Instruments,
www.mi-lasers.com)
