Researchers Build Integrated Waveguide for Ion Traps

Until now, delivering light to trapped ions required complex free-space optics that become impractical as the number of qubits increases. Now, the researchers have developed an ion-trap platform on borosilicate glass with an integrated femtosecond-laser-written waveguide for on-chip light delivery. This system achieves low-loss curved waveguides down to a radius of curvature of 6mm, and successfully demonstrated trapping, ion shuttling, and coherent operations using 729nm light guided through the integrated waveguide. Researchers have engineered a new ion trap using glass channels to deliver light to individual, electrically charged atoms, known as ions. This system uses femtosecond-laser-written waveguides, tiny pathways created with a laser, integrated directly into the trap’s structure; this separates the light delivery from the electrical controls. The design allows for curved light paths and is compatible with standard manufacturing processes, offering a potential route to building more complex quantum computing devices. Researchers have created a new platform for quantum computing using electrically charged atoms, or ions, held in place by electric fields, a microscopic holding pen for single atoms. Current systems rely on bulky free-space optics to deliver the light needed to control these ions, a method that becomes increasingly difficult as the number of qubits grows.

The team’s innovation integrates light delivery directly into the ion trap using microscopic glass tunnels, created with incredibly short pulses of laser light, that guide light like fibre optics. This approach physically separates the light paths from the electrical controls, enabling curved light delivery and compatibility with existing manufacturing techniques. Reduced waveguide curvature facilitates miniaturised ion trap optical circuits Low-loss curved waveguides now operate at radii down to 6mm, previously limited to 8mm, a key threshold for miniaturising complex optical circuits within ion traps. The tighter radius of curvature was previously unattainable due to increasing light loss when bending light within the small confines of a microchip; these new waveguides maintain signal strength despite the sharp turns. Extending single-mode operation to 405nm further broadens the platform’s utility, enabling manipulation of diverse ion species and quantum states. Precise control over laser parameters, including a 209-femtosecond pulse duration and 1MHz repetition rate, was central to waveguide fabrication, alongside careful sample positioning with. Laser-assisted cleaving created well-defined waveguide facets with a depth of approximately, enhancing light in- and out-coupling efficiency. While these 6mm radii represent a strong advance, long-term durability under continuous operation remains to be detailed, nor is scalability to densely packed, multi-ion array configurations yet confirmed. The fabrication process utilises a borosilicate glass ion-trap platform, delivering light directly to trapped ions and physically separating optical and electrical components. Further work will focus on optimising the laser writing process for increased waveguide longevity and exploring techniques for creating more complex, three-dimensional waveguide networks. Integrated photonics enable precise single-ion manipulation for future qubit arrays Increasingly sophisticated control over individual atoms, or ions, held in electromagnetic traps is demanded by the development of practical quantum computers. This integrated waveguide system offers a promising solution to the challenges of delivering light for ion manipulation, but scaling up from single-ion control to managing arrays of qubits remains a significant hurdle. The current demonstration focuses on a solitary ion, leaving the complex task of individually addressing multiple ions within a densely packed trap still to be resolved. Addressing this challenge requires developing methods for routing light to specific ions within the array without crosstalk or interference. A core engineering problem, delivering light to manipulate ions, the charged atoms used as qubits, without complex external optics, is directly addressed by this new platform. By integrating tiny channels that guide light directly onto the ion trap chip, the architecture is simplified and stability is improved, paving the way for controlling larger arrays of qubits. Compatibility with silicon-based integration suggests a pathway towards scalable quantum devices, potentially utilising existing microfabrication techniques to create high-density qubit arrays. A new ion-trap platform integrating light delivery directly onto the chip, physically separating optical and electrical components, has been demonstrated by the team at Universität Innsbruck and collaborating institutions. Microscopic channels created with a laser to guide light to trapped ions achieve a key 6mm radius of curvature for light paths, allowing for precise manipulation of individual ions and offering a potential building block for future quantum technologies. The researchers successfully created an ion-trap platform with light delivery integrated directly onto the chip using femtosecond-laser-written waveguides. This design simplifies the delivery of light needed to control individual ions, such as 40Ca^+, and improves the stability of the system. The fabrication process is compatible with silicon-based techniques, suggesting a route towards building larger, more complex arrays of qubits, and the authors plan to explore techniques for creating more complex, three-dimensional waveguide networks. 👉 More information🗞 Ion trap on borosilicate substrate with integrated femtosecond-laser-written waveguide✍️ Jakob Wahl, Alexander Zesar, Philipp Hurdax, Marco Schmauser, Victoria Schwab, Michael Pasquini, Marco Valentini, Clemens Rössler, Thomas Monz, Bernhard Lamprecht, Klemens Schüppert and Philipp Schindler🧠 ArXiv: https://arxiv.org/abs/2608.13207 Stay currentSee today’s quantum computing news on Quantum Zeitgeist for the latest breakthroughs in qubits, hardware, algorithms, and industry deals. Tags: