Understanding Laser Vibrometers

In focus

Two Optomet SMART Scan+ laser vibrometers.

Laser Doppler Vibrometry

How the Doppler frequency shift is converted into precise velocity and displacement signals—non-contact, without influencing the test object, and even at high frequencies.

3 min read

Fundamentals & technology

Optomet laser Doppler vibrometer measuring surface vibrations using reflected laser light.

Doppler Effect

Relative motion changes the perceived frequency of a wave. This principle forms the physical basis of optical vibration measurement.

3 min read

Vibration analysis of a vehicle using a laser Doppler vibrometer in an acoustic test chamber.

Vibration Measurement

Amplitude, frequency, phase, and mode shapes make the dynamic behavior of a component measurable. An overview of measurement parameters and analysis methods.

3 min read

All-in-one laser vibrometer system measuring vibrations on a gearbox.

Laser source

Wavelength and coherence determine signal quality, speckle behavior, and the usable measurement distance. HeNe and SWIR lasers are therefore suited to different surfaces.

5 min read

Schematic illustration of the measurement principle of laser Doppler vibrometry: The laser beam is split, reflected by the vibrating object, and superimposed with the reference beam; the resulting interference is used to derive the vibration signal.

Signal Processing

From the photodetector to reliable measurement results: demodulation, filtering, sampling rate, FFT, and the noise floor determine the quality of vibration data.

4 min read

From the field

Portable setup featuring a scanning 3D laser Doppler vibrometer for vibration measurements on printed circuit boards.

Application Report

FE model validation using scanning vibrometry

Validate FE models using full-field experimental data: measurement points on the FE model, non-contact scanning, FRF, mode shapes and MAC. Case study with 208 points.