Publications - XARION Laser Acoustics

SPIE. Photonics West 01/2024

Towards process control by detecting acoustic emissions during ultrashort pulsed laser ablation of multilayer materials

Authors:

C. Lutz, R. Sommerhuber, M. Kettner, C. Esen, R. Hellmann

Contents:

Ultra-short-pulsed laser ablation of thin multilayer materials can be monitored using XARION’s Eta450 Ultra optical microphone
It is possible to monitor the material transition between polymer and copper during laser ablation by observing a broad acoustic frequency spectrum between 100 kHz and 2 MHz in air, and by detecting a sudden change in acoustic energy
A direct correlation was found between increased detected acoustic energy and higher ablation rate

Link

Nature Communications 12/2023

Harmonizing sound and light: X-ray imaging unveils acoustic signatures of stochastic inter-regime instabilities during laser melting

Authors:

Milad Hamidi Nasab, Giulio Masinelli, et al.

Contents:

Laser Powder Bed Fusion Additive Manufacturing (LPBF AM) is a metal additive manufacturing process capable of directly producing intricate three-dimensional metallic components from CAD models
The present work deploys high-speed synchrotron X-ray imaging to scrutinize keyhole melting instabilities in LPBF and correlates these with the process’ acoustic emission (AE)
XARION’s optical microphone was used to measure airborne AE from the interaction zone between laser and material
The transition between conduction, stable keyhole, and unstable keyhole regimes, which leads to porosity formation and other instabilities, can successfully be discerned using the AE data

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Nature Communications 11/2023

Ultrasonic barrier-through imaging by Fabry-Perot resonance-tailoring panel

Authors:

Chung Il Park, Seungah Choe, et al.

Contents:

Ultrasonic imaging through nearly impenetrable metal barriers or the human skull remains an unresolved challenge
Applying a Fabry-Perot resonance approach and resonance tailoring panels the authors show that ultrasonic transmission through otherwise impenetrable barriers can be achieved
XARION's optical hydrophone (Eta100L Ultra) was employed to capture ultrasonic signals in the experiments
The newly developed method enables almost equivalent image quality as without barriers and has the potential to improve ultrasonic imaging

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Nature Photonics 10/2023

Acousto-optic modulation of gigawatt-scale laser pulses in ambient air

Authors:

Yannick Schrödel, Claas Hartmann, et al.

Contents:

XARION's optical microphone has been used to measure high-intensity ultrasonic fields
Schrödel et al. from DESY Hamburg showed deflection of gigawatt-scale laser pulses in air
Controlling coherent light is crucial in many fields, but modern photonics faces limitations from factors like wavelength and high optical powers
Using ultrasound-tailored gaseous media to efficiently deflect laser pulses offers new possibilities for resilient optical elements
To measure and characterize the ultrasound fields used for deflection, XARION’s Optical Microphone was used

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ICCM23 – International Conference on Composite Materials August 2023

Contact-Free Porosity Detection in Composite Parts by a Pore Resonance Mechanism

Authors:

M. Fuerst, M. Brauns, D. Bujdo, N. Panzer, B. Mauel, M. Dambaur, B. Fischer

Contents:

In collaboration with Airbus Helicopters Deutschland, XARION's Laser Excited Acoustics (LEA) technology was applied for fully contact-free porosity inspection of CFRP components, eliminating the need for couplants and immersion tanks.
XARION's broadband Optical Microphone (50 kHz – 2 MHz) detects laser-generated ultrasound through air, enabling reliable measurements independent of surface reflectivity, roughness, or part geometry.
In addition to the attenuation-based standard method, LEA can also exploit pore resonances to enhance the signal at defect locations, enabling both high-contrast imaging and direct pore sizing (270–530 µm) from the resonance frequency alone.
This pore resonance mechanism delivers high-resolution mapping of porosity distributions fully contact-free, making it a highly relevant solution for the inspection of CFRP parts in the aerospace industry.

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NDT & E International 10/2025

Elastic wave dispersion for heterogeneity characterization in cement-based media

Authors:

Nicolas Ospitia, Dimitrios G. Aggelis and Gerlinde Lefever

Contents:

The study uses elastic wave dispersion to analyze heterogeneities in cement-based materials.
XARION’s air-coupled, broadband, resonance-free Optical Microphone was applied, capturing ultrasonic dispersion with exceptional clarity – without contact to the specimen.
The analysis of the recorded waves allows identification of regions with differing mechanical properties, void sizes, and microstructural damage.
The results demonstrate how wave dispersion correlates with material heterogeneity, providing a quantitative basis for characterization and new possibilities for concrete diagnostics.

Science direct

Composite Structures 10/23

Low-velocity impact behaviour of biocomposite laminates reinforced by flax, basalt and hybrid fibres at various temperatures: Analytical, numerical and experimental results

Authors:

Valentina Giammaria, Simonetta Boria, Josef Pörnbacher, et.al.

Contents:

The impact behavior of bio-composites reinforced with flax, basalt and hybrid fibers was investigated
XARION’s LEA method was used to assess the internal damage of the composites after impact

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Wood Material Science & Engineering 05/2023

Supervised classification of wood species during milling based on extracted cut events from ultrasonic air-borne acoustic signals

Authors:

Mehieddine Derbas, Stephan Frömel-Frybort, Christian Laaber, Hans-Christian Möhring, Martin Riegler

Contents:

Monitoring during wood processing is gaining momentum in order to increase efficiency and enable adaptive manufacturing
Acoustic monitoring is particularly suited for the cutting/milling process
Derbas et al. developed a Machine Learning model to distinguish between wood species with up to 93% accuracy using single-cut events

Link

Optics and Laser Technology 04/2023

A comprehensive study on water jet guided laser micro hole drilling of an aerospace alloy

Authors:

Levent Subasi, Mustafa I. Gokler, Ulas Yaman

Contents:

Water-Jet Guided Laser Drilling is a process particularly suited for manufacturing of thin and long holes in metals
In this study, the Optical Microphone has proven to be a suitable sensor for monitoring the hole depth and the moment of hole breakthrough in real-time

Link

12th International Electric Drives Production Conference (EDPC) 01/23

Inline Process Monitoring of Hairpin Welding Using Optical and Acoustic Quality Metrics

Authors:

Markus Omlor, Johannes Reith, et.al.

Contents:

XARION´s Optical Microphone was used to capture airborne ultrasound generated during the hairpin welding process
A multitude of welds were performed under varying quality-affecting parameter conditions, such as positioning misalignments or focal height and laser power deviations
It was found that the real-time ultrasound emission could be utilized as an early indicator for predicting the important quality criterium of final cross-sectional area of connection

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