Innovation by government and industry continues as major theme of SPIE Defense + Commercial Sensing

Innovation continued as a major theme on day three of SPIE Defense + Commercial Sensing (DCS), including efforts that have spanned decades, such as the US civilian space program and development of practical directed energy weapons. The conference is being held 30 April to 4 May in Orlando, Florida, USA.

The day kicked off with a plenary talk by Alan X. Wang of Baylor University. He detailed some of his group’s efforts to use the unique properties of diatoms, abundant microalgae, as photonic crystals. Specifically, his group has developed diatom photonic crystals with plasmonic nanoparticles as ultrasensitive, low-cost substrates for surface-enhanced Raman scattering (SERS) sensing and imaging.

There are more than 200 species of diatoms, and they produce 40 percent of the planet’s oxygen. “Basically, they are the foundation of the food chain and ecosystem of our globe,” Wang said. They are so abundant, diatoms (as diatomaceous earths) can be ordered cheaply and in bulk on Amazon.

But for Wang, who began investigating diatoms as a nanoparticle substrate on the suggestion of a graduate student, the real wonder is how they can be used as photonic crystals. “You can easily functionalize the surface [of biosilicate diatoms] and use that functional agent to capture different types of biomolecules,” he said. And because of the purity of the material, it can be used for biosensing.

The Wang group has reported unique microfluidic flow, analyte concentration, and thin-layer chromatography on diatom biosilica that enables separation, detection, and analysis of complex chemical and biological samples.

Alan Wang  and his lab group at Baylor University have been developing diatom photonic crystals with plasmonic nanoparticles for surface-enhanced Raman scattering sensing and imaging. Credit: Lotus Eyes Photography

“We have developed a lab-on-a chip technology based on TLC-SERS sensing and successfully applied it to various applications including food safety, illicit drug residue sensing, and biomarker detection,” Wang said. He detailed how the nanoparticles can also be used for vapor sensing to look for explosive materials like TNT, and as disease antibody detectors when the surfaces of diatoms are functionalized with biomolecules.

The sensing mechanism is not limited to SERS, Wang said. “We have demonstrated fluorescence imaging, but also you can apply that to infrared absorption or other types of plasmonic resonance sensing because this photonic crystal enhancement is universal. “This is a very versatile platform that can be integrated with different types of functional materials to provide a more-rich functionality.  

The second plenary talk by Army Research Lab consultant Richard M. Buchter, looked at the “race of the space barons.” He noted the efforts of billionaires like Elon Musk and Jeff Bezos to commercialize space, colonize the moon and other planets, and possibly exploit mineral resources such as the rare earths needed for battery technologies.

As an innovation expert, Buchter compared the different approaches to space exploration by government and the private sector. “What we are looking at now with space 2.0 is not only how do we transform our world but potentially other worlds.”

Richard M. Buchter of the Army Research Lab discussed attributes of Space 2.0 and how they may impact multidomain communications in the future. Credit: Lotus Eyes Photography

At the US National Aeronautics and Space Administration, the Artemis program to return to the Moon includes the agency’s Space Launch System “that took one to two years get to that rocket in place, and it was also an effort that’s been going on for an excess of 10 years,” he said. The reason: an approach that demands perfect outcomes — i.e. a successful launch into space — from the start.

Investors like Elon Musk in Silicon Valley, he said, are applying completely different methods. For commercial interests, time is money, which means production times must be continually compressed with an acceptance of learning from failure. Exhibit A of this approach was the recent SpaceX launch of its Heavy Lift Launch System and Starship space vehicle that failed to separate shortly after launch, destroying the rocket and vehicle and severely damaging the Texas launch pad. But true to form, the company was not dismayed, rather celebrated their opportunity to learn and do over.  They are able to build two Starships per week and have ready replacements to try again.

An industry panel discussion of directed energy (DE) weapons, on the floor of the DCS Exhibition, was a spirited discussion of the US government’s decades long effort to develop laser weaponry as envisioned by President Ronald Reagan in the 1980s.

“It’s been 40 years. We don’t have this technology as far as I know yet,” said moderator Robert Walker, who is vice president of strategy and business development at Leonardo. In some ways, he noted, “we started with the hardest problem first.”

Panelists included Sandra Biedron, executive director of the Directed Energy Professional Society; Martin C. Richardson, director of the Center for Directed Energy at University of Central Florida; Andrew Held, a vice president at Coherent; Christopher D. Marshall of Lawrence Livermore National Laboratory; and John Lund of the University of Alabama and the US Army.

Walker noted a recent Government Accountability Office report that gave the Army high marks on its DE technology development. In their discussion, the panelists noted ongoing barriers to development, including Defense Department procurement policies, supply chain issues for complex laser systems, workforce shortages, and the need to train warfighters on both operation and repair of laser systems to be used on the battlefield.