Rami Arieli: "The
Laser Adventure" Section 9.1.2 page 1
9.1.2 Straight line marking,
or plan of reference.
Many daily applications require a precise reference
line for alignment.
Examples are:
- Laying pipes of gas, water, electricity, etc.
- Digging tunnels under-ground (such as the one under the English
Channel between England and France).
- Alignment of mechanical systems.
- Marking spots for pointing invisible radiation from another laser (such
as Nd-YAG or CO2 lasers). The visible laser radiation is aligned parralel to the invisible radiation, such that it mark the place where the invisible beam is pointing.
- Marking a reference plane for construction:
By using a vibrating (or rotating) mirror
to reflect a visible laser light, a perfect plane is defined in space.
The mirror is vibrating around one axis, so the light is reflected into
consecutive angles continuously, thus defining a perfect plane. Since the
vibration of the mirror is at a frequency greater than the persistence
of vision in the brain, the viewer see a plane of light. This plane helps
aligning walls, sealing, etc. in industrial construction.