Laser-scanning vibrometers

A single-point vibrometer measures vibration at a single point along the laser axis.
A scanning vibrometer automatically directs the laser across many measurement points and generates a full-field vibration shape. This allows mode shapes, natural frequencies, and spatial vibration distributions to be visualized.

Yes. For three-dimensional vibration analysis, Optomet uses a system consisting of three scanning vibrometers working together as a 3D scanning unit. Each vibrometer measures vibration from its own direction. The three systems are time-synchronized, align their measurement points, and exchange essential control and reference signals during the measurement.

From the three velocity components recorded at each measurement point, the system calculates the complete motion in X, Y, and Z directions. This allows complex 3D mode shapes and spatial motion directions to be represented precisely.

SMART 3D-Scan

Optomet scanning vibrometers operate with eye-safe laser sources.

The invisible SWIR measurement laser (1550 nm) is classified as Laser Class 1 (< 10 mW) and requires no safety goggles. Some systems can alternatively be operated with a visible HeNe measurement laser (632.8 nm), classified as Laser Class 2 (< 1 mW), also considered eye-safe. For alignment, a visible pilot laser is used, also Laser Class 2 (< 1 mW). All lasers are safe in normal operation and specified in the technical datasheets of each device.

Depending on the application, Optomet uses different laser sources. Standard systems use SWIR lasers (1550 nm), which offer high optical sensitivity and require no surface preparation. Alternatively, visible HeNe lasers (632.8 nm) may be used depending on the application area. The laser source is selected during the technical configuration.

Scanning vibrometers always measure the individual points sequentially. The laser beam automatically moves across the defined grid, and each point is recorded separately. Using a reference signal, the time-offset individual measurements are then brought into correct phase alignment, resulting in a complete vibration shape.

For Full Body Scans, multiple scanning vibrometers operate in parallel.
Each device still measures its points sequentially, but they cover different areas of the object simultaneously. In SMART Lab, all points are merged spatially and temporally.

• Single scanning vibrometer: points are measured sequentially.
• Full Body Scan (multiple vibrometers): several sequential scans run in parallel and are synchronized.

The excitation method depends on the measurement approach and the goal of the investigation. For defined, reproducible vibrations, active excitation sources such as a shaker, modal hammer, or piezo actuator are commonly used. In operational measurements, the structure can be excited by real influences such as engine operation, wind, or process forces.

Typical excitation methods:

• Modal hammer for impulse excitation
• Shaker for defined, frequency-variable, or broadband excitation
• Piezo actuators for high-frequency or local excitation
• Sound fields (e.g., loudspeakers) for acoustic excitation
• Real operating conditions when the behavior under load is to be analyzed
• Internal signal generator (in Optomet scanning vibrometers) as a defined, integrated excitation source

For scanning vibrometers, the software solutions SMART Lab and OptoSCAN offer complete integration of scanning grids, device control, and data analysis.

However, their use is not mandatory: all measurement data can also be output via digital or analog interfaces and processed in any external analysis environment.

Usage options:

• SMART Lab / OptoSCAN / OptoGUI for full control, visualization, and analysis
• External software (e.g., MATLAB, LabVIEW, Python, FEM tools, or custom solutions) via open data and control interfaces
• Analog or digital raw data output (e.g., velocity, acceleration, displacement) for direct downstream processing

This allows the vibrometer to be used both as a fully integrated measurement solution and flexibly as a data source within existing analysis or automation systems.

Scanning vibrometers can be integrated into automated test stands and existing measurement chains through open interfaces. Measurement data is available both digitally and analogically and can be transferred directly into external systems.

Interfaces and integration:

• Gigabit Ethernet for digital measurement data and control commands
• Analog outputs for velocity, acceleration, or displacement
• External triggers for synchronized measurement processes
• Open data formats for processing in custom systems
• Compatible with automated sequences, e.g., for test-bench or end-of-line applications

This allows the vibrometer to be used either as a standalone measurement system or as part of a fully automated setup.

The duration of a scanning measurement depends on several factors such as desired frequency resolution, number of measurement points, and the vibration frequencies being investigated. For a quick overview, the object can be scanned at up to 50 points per second.

The required number of measurement points depends on the spatial complexity of the modes being investigated. Higher frequencies have shorter wavelengths and more nodal lines, requiring a denser spatial sampling to capture the vibration shapes accurately.

SMART scanning vibrometers can record up to 512 × 512 measurement points across the defined measurement area. This allows even complex structures to be analyzed fully and with high resolution.

No. The SWIR lasers of Optomet laser-scanning vibrometers enable reliable measurement without reflector tape, even on dark or rough surfaces. The high sensitivity and strong return signal provide a stable, high signal-to-noise ratio even under challenging conditions.

The scanning vibrometer can be used across a wide range of distances. Depending on the setup and object size, the following working distances are possible:

• Up to 100 m distance for standard scanning applications – ideal for large structures or hard-to-access measurement objects.
• Minimum working distance from approx. 6.5 mm when measuring very small objects or fine details.

This allows the system to reliably cover both short-distance measurements in the micrometer range and long-distance measurements in industrial environments.

Yes. Optomet’s SMART Lab software supports the import of 3D models. Users can load their FEM geometries and place measurement points directly on FEM nodes. This makes it possible to precisely compare measurement data and simulation, enabling efficient validation and optimization of FEM models.

An Optomet laser-scanning vibrometer covers a very wide size range:

• Very small structures < 1 mm², e.g., MEMS components
• Large objects > 10 m², such as housings, machine parts, or large components

With the Optomet SMART Series, multiple scanning vibrometers can be synchronously networked, enabling measurements on entire vehicles or aircraft (“Full-body vibrometry”).

With a single device, frequencies from DC to 50 MHz can be detected – suitable for slow vibrations as well as for very high-frequency dynamic processes.