BOREAL LASER GasFinder2, Руководство по эксплуатации

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8.3
Boreal Laser Inc. GasFinder2 Operation Manual — Tutorial July 17th 2017
Retrorefl ectors
The laser beam is transmitted to a retrorefl ector made with a special type of corner cube
arrangement. This causes the signal to be refl ected directly back to the detector in the
transmitter enclosure. With the appropriate number of refl ectors, path lengths up to 750m
can be traversed.
Most mirrors refl ect light the same way as a fl at, glass
bathroom mirror, where the angle of incidence(i) =
the angle of refl ection(r). A bathroom mirror has the
refl ective coating on the rear, behind the glass. See
fi gure 4.
A retrorefl ector is different in that the refl ected light
returns in the same direction as the incident light.
The beam is refl ected 180 degrees. A retrorefl ector
is like a section through a corner and has three
faces that form the inside corner of a cube. Some
highway refl ectors are everyday examples. See
fi gure 5.
Because retrorefl ectors used for laser gas detection
have the refl ective surface on the front, the base
material can be glass or metal. The surface coating
is usually a very thin layer of gold or sometimes
silver. This means that cleaning the fragile coating
is very diffi cult and is done with an air brush to avoid
touching the surface.
75 Element retro
6 Retros
Fig. 4 Flat Mirror
Fig. 5 Retrorefl ector