Plane-Mirror Interferometer
SP-TR Series
 Design and Operation 
Our triple-beam interferometers combine three interferometers into a single unit and thus are capable of making simultaneous, nanometer-precision, triaxial length measurements.
They are 
intended for incorporation into customer supplied systems.
Angles may be determined with high precisions from the differences between pairs of length measurements and the respective beam separations involved.
The dynamic ranges for pitch and 
yaw measurements are approximately two minutes of arc.
A HeNe laser emitting an ultrastable wavelength supplies all three interferometers so that all three length measurements will be based on the same reference length.
A single fiberoptic 
lightguide conducts its output beam to the interferometric sensor head.
Motions of the moving mirrors are converted into modulated 
signals that are transmitted to an electronic power supply/ signal processing unit.
A HeNe laser serves as the light source for the miniature interferometer and is frequency stabilized on models with large dynamic ranges. Compensation of environmental influences form the basis for high metric precisions and are achieved through the correction of laser wavelengths.
A PC running a custom software 
package is employed for operating the electronic modules and displaying measurement results.

 Major Performance Features 
• Simultaneous, ultraprecise, triaxial length measurements as well as pitch and yaw angle measurements
• A single laser supplies the beams for all three measuring arms 
• Factory made calibration of beam separations

 Operating Principle 

 Laser-interferometric measurements on guides and translation, microscope, and positioning stages High precision pitch and yaw corrections during biaxial or multiaxial length measurements Calibrating metrological equipment and machine tools Differential measurements (dilatometry,materials testing) Angular measurements over extended ranges (> ± 2 arcmin; available on special order)