Novel Diagnostic Probes Plasma Evolution
Plasma is an ionized gas, often called the fourth state of matter. Understanding plasma’s properties is critical for applications in fusion energy, astrophysics, and semiconductor manufacturing. However, observing how high-density plasmas evolve is challenging because timescales are short (trillionths of a second) and behavior is complex and unpredictable.
In a study published in the September 20, 2025, issue of Optica, Livermore researchers describe their single-shot advanced plasma probe holographic reconstruction (SAPPHIRE) diagnostic, which captures plasma evolution at 100 billion frames per second using a single laser shot. “In most high-energy, high-intensity laser experiments, we take a single image per shot,” says Livermore scientist and lead author Liz Grace. “However, we need to capture as much information as possible at one time.”
SAPPHIRE uses a chirped laser pulse in which the redder (longer wavelength) frequencies in the laser pulse follow the bluer (shorter wavelength) frequencies. The beam is split into two: one half travels through the plasma where it refracts and warps, and the other half remains unchanged. SAPPHIRE separates the halves, then recombines them to form interference patterns for each frequency that can together be used to retrieve a time-resolved map of electron density, providing a detailed movie of how the plasma changes over time. Tested on helium–nitrogen gas jets, SAPPHIRE could also probe pulsed-power plasmas, waveguides, plasma optics, and laser-based particle accelerators.
Contact: Liz Grace (925) 424-2254 (grace11 [at] llnl.gov (grace11[at]llnl[dot]gov)).
Additive Manufacturing Delivers Tiny Ion Traps
Lawrence Livermore researchers and University of California collaborators have produced miniaturized quadrupole ion traps using an ultrahigh resolution 3D printing technology. Their work, published in the September 30, 2025, issue of Nature, demonstrates a promising technique for fabricating hardware for quantum computers.
Quadrupole ion traps use four electrode poles to create an oscillating electrical potential that traps ions by overriding their natural vibration. The traps keep ions confined for hours before they escape, and if the ions are cooled to their ground state—their lowest possible energy—they can function as quantum bits (qubits), the basic unit of information in a quantum computer. The team fabricated the submillimeter-scale traps using two-photon polymerization, wherein a tightly focused laser hardens a liquid resin to create intricate 3D shapes. A fully miniaturized trap (shown in the image below left) can be printed in 14 hours, or electrode structures on a substrate in 30 minutes, enabling rapid prototyping of complex geometries.
The newly developed devices confine calcium ions with trapping frequencies, coherence times, and gate error rates comparable to the best devices and support single-qubit and two-qubit operations. Livermore physicist and co-author Kristi Beck, the director of the Livermore Center for Quantum Science, says, “This type of technological change could move ion traps from working well with just a few ions to performing real computations in quantum computers.”
Contact: Xiaoxing Xia (925) 925-423-6489 (xia7 [at] llnl.gov (xia7[at]llnl[dot]gov)).
More Efficient Ethylene Production
Carbon dioxide (CO2) electrolyzers—electrochemical devices that use electricity, water, and a copper catalyst to convert CO2 into valuable chemicals such as ethylene—show promise for increasing domestic chemical manufacturing by diversifying chemical feedstocks. However, their low energy efficiency has limited these devices’ widespread deployment. Livermore researchers have designed a polymer ink, or ionomer, that controls how CO2 and water move through CO2 electrolyzers to improve the conversion process by lowering the input energy required. This research, published in the November 5, 2025, issue of Chem Catalysis, illustrates a path forward for scaling the technology to commercially relevant sizes.
The team’s sandwich-sized electrolyzer consists of several thin stacked layers, including specialized electrodes and membranes that drive the chemical reactions. The cathode’s copper surface accelerates CO2 reduction and controls which products form. Livermore’s ionomer is sprayed as a coating on top of the copper layer to carefully balance and direct the device chemistry. “The ionomer acts as a traffic controller for molecules,” says Livermore scientist and paper co-author Maxwell Goldman. “Without it, too much water can flood the device, or too little water can starve the reaction.”
Different ionomers were synthesized and experimentally validated to determine those that optimally controlled water content and uptake. Advanced characterization and multiphysics models confirmed the underlying physiochemical properties of the material. Laboratory scientist and co-author Aditya Prajapati says, “The selected ionomer lowered the overall voltage needed to run the device, which means it requires significantly less electricity to make the same amount of product.”
Contact: Aditya Prajapati (925) 422-6094 (prajapati3 [at] llnl.gov (prajapati3[at]llnl[dot]gov)).
