Glossary
attoSENSORICS technical terms
Fabry-Pérot Interferometer
Our FPS and IDS Sensor Systems rely on a low-finesse fiber-based
Fabry-Perot Interferometer. A great advantage of this technology over
other displacement sensing techniques is their electronic-free sensor
heads. The physical dimension of the sensor head is reduced to the
millimeter range. This miniaturization makes the sensor ultra-compact
and also compatible with extreme environments such as ultra high
vacuum and low temperature.
The fiber-based design allows flexible alignment, thus making multiaxis
measurements and large distances of fiber length (even covering
kilometer long distances) an easy task.
Environmental Compensation Unit (ECU)
The ECU provides a fully automated refractive index compensation
for contactless interferometric measurements at ambient conditions.
Variations in air pressure, temperature, and humidity are recorded and
used to automatically compensate for changes in the refractive index.
Focusing Sensor Head
The focusing sensor heads D4/F17 (sensor head diameter of 4 mm
with a focal length of 17 mm), M12/F40, and D12/F2.8 are suitable to
measure on a wide range of target materials as well as target surface
qualities with low, medium, or high surface reflectivity. For
example, the focusing sensor heads make it possible to measure on a
BK7 glass object with a reflectivity of only 4 %. The sensor head M15.5/F40
includes a flexure structure to adjust the beam path angle with ±1°.
Working Distance
Distance between the front side of the sensor head and the target
where a continuous measurement is possible.
Absolute Distance
Distance between the end of the fiber, which is represented by the
mechanical stop, and the target.
Focal Length
The focal length F is the distance between the front side of the sensor
head and the focal point.
Alignment Tolerance
The angular alignment tolerance represents the target‘s tilt range in
respect to the laser beam (α in the figure below). The laser beam might
not be parallel to the central axis of the sensor head (β in the figure
below). At retroreflectors, the center of roration is defined as the
center of the retroreflector.
α
Sensor Head
Collimating Sensor Head
The sensor head M12/C7.6 (sensor head with a M12 metric
thread and a beam diameter of 7.6 mm) is suited with a collimating
optics type especially designed for the use with retroreflectors. It is
optimized to measure over longer distances.
±2°
target‘s tilt range
β
F
working distance
absolute distance