Know-How

Laser Doppler vibrometry (LDV) is currently the method that offers the best displacement and velocity resolution and is used in many fields of basic science. It enables femtometer amplitude resolution and is linear and therefore has a consistent amplitude right up to the very high frequency ranges – reaching up to 8 GHz.

In order to understand the measuring principle of optical vibration sensors, we must first transfer the phenomenon of the Doppler effect to light waves: if a beam of light is reflected by a moving object, its frequency changes in proportion to the speed of the object. This frequency shift contains the velocity information that is used by the laser Doppler vibrometer as a measurement signal.

Stroboscopic video microscopy (SVM) makes use of the fact that high-frequency vibrations at component level can be visualized with normal video cameras when rapid movements are visually frozen using short flashes of light.

The multi-path interferometry QTec® means reinventing laser vibrometry by eliminating the root cause of noise with engineered surfaces for highest optical sensitivity, enabling high-fidelity measurements on all surfaces To achieve these benefits in, QTec Vibrometers use for the first time a multi-path interferometer and reception diversity to recombine the best reading from different perspectives.

QTec® is an advanced laser Doppler vibrometry technology by Polytec that enables high-precision, non-contact vibration measurements. It features high optical sensitivity, best signal-to-noise ratio on all surfaces, a broad frequency bandwidth, and no mass loading, making it ideal for demanding measurement tasks.