Scanning Acoustic Microscopy

Acoustic microscopy is based on the pulse-echo principle, in which a high-frequency transducer transmits rapid ultrasonic pulses and receives the returning signals. The transducer contains a piezoelectric element that converts electrical signals into precise ultrasonic waves. These waves are coupled into the sample via a coupling medium — such as deionized water. The ultrasonic waves are focused onto the sample, and reflections from internal structures are captured by the transducer. An analog-to-digital converter (ADC) digitizes the received signals, while advanced trigger electronics control the transmission and reception cycles. The result is a high-resolution, non-invasive imaging of the sample's interior, displayed as a grayscale image.

Systematic and very precise

The transducer scans the sample line by line (in grids) on the XY plane and on request — in case of samples with bows or protruding elements — in the Z direction and then displays the electromagnetic pulses as pixels with specific gray values.

The information from the individual pixels is used to generate an image showing all the recorded signals. To begin with, the ultrasound reflection at the sample surface is displayed. If the sample is intact, the signal is reflected again a second time at the rear side of the sample. The time difference of arrival of the two signals from the upper and lower side of the sample yields information about its thickness. If the sample contains a defect, this interface — between sample and defect — will also cause sound reflection to occur.

Unrivaled and Specific

Acoustic microscopy operates using frequencies that extend to the gigahertz range. As a general rule, the higher the frequency, the greater the achievable resolution and the lower the penetration depth of the sound waves.

Since the attenuation in the coupling media increases quadratically as the frequency rises, the lens must be brought as close as possible to the sample under investigation. This low working distance and the difficulty of creating transducer arrangements offering high local resolution require a type of scanning microscopy in which the sample is investigated pixel by pixel.

The ongoing further development of their high-resolution transducers enables Analytical Systems to improve the measurement accuracy. The ultrasound microscopes currently offer the highest frequency range up to a maximum of 1,000 MHz, delivering resolutions all the way down to 0.8 µm. Naturally, this depends on the material and the density of the sample to be investigated.

From laboratory instruments through to semi-automated devices all the way to fully automated systems, by combining ground-breaking technologies and sophisticated engineering solutions, we develop high-performance acoustic microscopes and software that can be optimized to suit your investigation requirements and materials. Our versatile SAM product lines are characterized by intuitive analysis technologies — made in Germany with an unmatched price-performance ratio.

The basis of our ultrasound technology forms a common component platform, which is completed by application-specific modules for individual solutions. They differ in terms of their hardware (optionally expandable), scanner type and its travel, as well as the transducer. As a matter of principle, our transducers are compatible with all systems.

Beyond SAM systems, our expertise extends to advanced Ultrasonic NDT systems designed for larger, complex components and industrial inspection tasks. These systems build on the same core ultrasound platform while offering multi‑axis motion, expanded scan envelopes, and application‑specific automation for high‑precision evaluation across diverse part geometries.

To our Ultrasonic NDT systems