News Feature | May 4, 2022

Bright Ideas — Fraunhofer ISE Doubles Solar Cell Processing Output, LLNL Finds 3D Printer Defects With Laser-Based Ultrasound

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By Abby Proch, Editor

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Lawrence Livermore National Lab (LLNL) researchers have developed a diagnostic tool that uses surface acoustic waves created by laser-based ultrasound to detect small surface and sub-surface imperfections in laser powder bed fusion (LPBF) 3D-printed metal objects. The new process reportedly shortens the time it takes conventional X-ray CT detection from days down to minutes. But while the new method bodes well for in situ diagnostics of LPBF printing, it is limited to voids of certain sizes and depths. However, researchers still say it may be a quick and useful tool for qualifying new and existing LPBF machines “after changes to metal powder feedstock or modifications to the melt laser power or scan speed.”

In other research news, Fraunhofer ISE has developed a new continually operating high-throughput solar cell processing system that creates roughly 500,000 contact openings per second to produce over 15,000 solar wafers per hour. The incredible output for large-scale wafers, like the M12 and G12, is double the current industry expectation of 7,000 wafers/hour. Key to its speed and precision is polygon scan technology in which a mirror wheel scans the laser over a sample at more than 3,000 km/h — about 20 times faster than traditional scanners. The expected outcome is a drastic reduction in cost and rise in production, says the research team.

At the University of Virginia, a research team is using a $2.4 million three-year grant from DARPA’s GRYPHON (Generating RF with Photonic Oscillators for Low Noise) program “to translate the purity and stability of high-frequency optical signals into the microwave regime.” Assistant Professor of Electrical and Computer Engineering Xu Yi says the fledgling system will eventually work up to 100 GHz, at frequencies 20x higher than that of Wi-Fi and 3x that of 5G. Typical systems multiply low frequencies while his will “start high and divide down.” The UVA team is on track to hit a key requirement of the GRYPHON program: offering an order of magnitude improvement in size, phase noise, and/or frequency span.

Three years into a collaboration between Harvard University and University of Sydney, scientists there are claiming a silicon carbide electro-optic modulator may be yet another step closer to viable quantum computing. This “smaller, stronger, cooler, faster, and more cost-effective” modulator reportedly allows higher optical signal-to-noise ratios for communications in data center, 6G networks, and satellites, too.

It’s not every day silkworms wiggle their way into the photonics spotlight, but scientists have developed an edible code made of the worms’ silk fibroin encoded with fluorescent proteins to better preempt counterfeit medications. Scientist have developed an imperceptible and safe-to-eat matrix array that can be scan and identified using a smartphone and supporting app.  Until now, anticounterfeiting methods have proven unusable at scale and frequency because of their toxicity. The new dosage-level identification is also preferable to package-level identifiers and is simple for both providers and patients to use in determining medications’ authenticity.

In research news, Tokyo Tech is developing a new lensless camera system using a thin mask, image sensor, and machine learning to reliably produce quality images while also cutting down on computation time. The research team’s algorithm allows it to use multiplexing to overlap local pixels with global data and learn image features in a hierarchical representation, thus overcoming the limitations of conventional convolutional neural network-based deep learning.

And in business, sensiBel, maker of laser-based audio technology capable of rendering studio-quality sound, has received a €15 million backing from the venture capital division at Trumpf. sensiBel’s optical MEMs microphone marries remarkable sound quality with an ultra-miniature form factor. One of the device’s hallmarks is its ability to capture speech clearly over long distances and in noisy environments. The funds are said to support further research as well as mass production efforts.

Finally, in medical imaging news, Hamamatsu Photonics and Dotphoton have partnered with one another to pair Hamamatsu’s high-quality scientific cameras with the latter’s raw image compression software. The duo both recognize an increasing need in the scientific research community and pharmaceutical industry for high-quality, high-volume biomedical image processing and storage. Hamamatsu’s ORCA camera will now support Dotphoton’s Jetraw software and in doing so will help satisfy the need for a sustainable method for image processing and storage that reduces data center’s impact on rising CO2 levels.