Laser-driven Particle Accelerator Made Ten Thousand Times Smaller

Dielectric laser accelerators (DLAs) provide a compact and cost-effective solution to this problem by driving accelerator nanostructures with visible or near-infrared (NIR) pulsed lasers, resulting in a 10,000 times reduction of scale. Current implementations of DLAs rely on free-space lasers directly incident on the accelerating structures, limiting the scalability and integrability of this technology. Researchers present the first experimental demonstration of a waveguide-integrated DLA, designed using a photonic inverse design approach. These on-chip devices accelerate sub-relativistic electrons of initial energy 83.4 keV by 1.21 keV over 30 µm, providing peak acceleration gradients of 40.3 MeV/m. This progress represents a significant step towards a completely integrated MeV-scale dielectric laser accelerator.

Dielectric laser accelerators have emerged as a promising alternative to conventional RF accelerators due to the large damage threshold of dielectric materials the commercial availability of powerful NIR femtosecond pulsed lasers, and the low-cost high-yield nanofabrication processes which produce them. Together, these advantages allow DLAs to make an impact in the development of applications such as tabletop free-electron-lasers, targeted cancer therapies, and compact imaging sources.

They have designed and experimentally verified the first waveguide-integrated DLA structure. The design of this structure was made possible through the use of photonics inverse design methodologies developed by the team members. The fabricated and experimentally demonstrated devices accelerate electrons of an initial energy of 83.4 keV by a maximum energy gain of 1.21 keV over 30 µm, demonstrating acceleration gradients of 40.3 MeV/m. In this integrated form, these devices can be cascaded to reach MeV-scale energies, capitalizing on the inherent scalability of photonic circuits. Future work will focus on multi-stage demonstrations, as well as exploring new design and material solutions to obtain larger gradients.

Fabricated single-stage accelerator. SEM image of a single stage accelerator of 30 periods fabricated on a 500 nm SOI stack. The accelerator sits on a 25 µm tall mesa structure to provide clearance for the input electron beam.

Arxiv – On-chip integrated laser-driven particle accelerator

13 thoughts on “Laser-driven Particle Accelerator Made Ten Thousand Times Smaller”

  1. The accelerator is used to excite a sub critical core of fissile material. Each proton turned into a neutron (via Be foil) and enters a lump of plutonium or something that is enough to amplify the energy a huge factor, but not big enough to sustain itself because more of the neutrons are lost than created.

    Voila! Desktop fission!

    OK, you can’t get within hundreds of meters of that particular desk without radiation poisoning, but you know… same as fusion there.

  2. Use of accelerators to generate fusion power has severe problems with fundamental thermodynamic limits. Google “braking radiation”.

  3. Pretty sure you could make some fusion and that it would not be practical (economically).

  4. mr Fusion goes at the back of the car. should be far enough. inverse square law should reduce neutron flux

  5. Fusion reactions generally put out high energy neutrons &/or gamma rays. Even the so called aneutronic reactions emit x-rays from the plasma & usually have some side reactions creating neutrons or gammas. So even if the reactor itself is desktop size you will want a meter or 2 of something absorbing the radiation, both to keep the operators safe & to become the hot end of a heat engine for doing useful work like generating electricity.

  6. No more multi-billion dollars particle accelerators means this is the way forward for particle physics.

    Which is a good thing. Too much budgetary largesse is bad for scientific ingenuity.

  7. The larger (but still quite small) wakefield accelerators were claiming ~1 GeV/m a few years ago, IIRC. But the ones here are chip-scale, which is impressive in other ways.

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