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High linearity probe

LM 20/50

Fiber-coupled, highly linear probe for high-precision tactile thickness measurement and calibration

laser interferometric precision probe for tactile length/thickness measurements

linearity ≤ ±2 nm

measuring force fixed adjustable 0.5 ... 1.5 N

high linearity over the entire measuring range

constant probe measuring force over the entire measuring range

open interfaces for OEM software under Windows and Linux

The LM series laser interferometric probes are precision linear encoders. With these probes, tactile measurements are possible over a measuring range of 20 or 50 mm with nanometer accuracies. The highly linear length gauges are compatible with conventional measuring systems due to their size and the clamping shaft diameter of Ø 8 mm h6.
The integrated laser interferometer converts the measuring movement of the motor-driven measuring spindles into an interference signal. This optical measurement signal is transmitted by fiber optics to the optoelectronic supply and evaluation unit and output as a length value. The stylus quill and the integrated interferometer are adjusted to each other, taking into account the minimization of abbe and alignment errors. 
The stable HeNe laser, whose light is fed to the laser interferometer via optical fibers, and the correction of environmental influences on the laser wavelength are the basis for the high measuring accuracy. Operation and display are either via a separate display or via a PC with suitable software.

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Technical data

20 mm,
50 mm

0.1 nm

Areas of application

highly linear probe

Abbe-error-free interferometric length measurement

constant measuring force over the complete measuring range

suitable as a built-in measuring system

motorized drive unit

suitable for thickness measurement of highest accuracy in the double probe version

Ideal for

quality control 


thickness measurement

gauge block inspection

Measuring principle of the tactile probe

You want to know
whether the Probe LM 20/50 is the right solution for your measurement tasks?

Our SIOS experts will be happy to visit you on site. Together we can find a quick solution for your application and carry out the first test measurements in your environment.

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Related software


Software for probes

simple thickness measurements

probe control and measurement data acquisition


Software for data acquisition and visualization

Universal software for all SIOS interferometers

Basic functions for data acquisition

Synchronization settings

Your contact

Falko Seyfferth

Application Engineer

+49 (0) 3677 64 47-49

Are you interested in the Probe LM20/50?

We will be happy to make you a suitable offer.

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