²²⁹ThF₄ thin films for solid-state nuclear clocks

Area of Science:

• Nuclear Physics
• Quantum Optics
• Materials Science

Background:

• The Thorium-229 (²²⁹Th) nuclear isomeric transition is a promising candidate for next-generation nuclear clocks.
• Current methods using ²²⁹Th-doped crystals face challenges due to material scarcity, radioactivity, and complex handling.
• Advances in ²²⁹Th spectroscopy necessitate scalable and robust target materials for various applications.

Purpose of the Study:

• To develop a scalable and efficient method for preparing ²²⁹Th spectroscopy targets.
• To demonstrate the feasibility of using ²²⁹ThF₄ thin films for nuclear clock applications.
• To reduce the amount of radioactive material required for ²²⁹Th-based technologies.

Main Methods:

• Thin films of Thorium-229 tetrafluoride (²²⁹ThF₄) were grown using physical vapour deposition.
• Laser excitation was performed on the ²²⁹Th nuclear transition within the ²²⁹ThF₄ thin films.
• The radioactivity of the ²²⁹ThF₄ thin films was compared to traditional ²²⁹Th-doped crystals.

Main Results:

• Successfully demonstrated laser excitation of the ²²⁹Th nuclear transition in ²²⁹ThF₄ thin films.
• The thin film approach requires only micrograms of ²²⁹Th material, significantly less than previous methods.
• ²²⁹ThF₄ thin films are compatible with photonic platforms and nanofabrication, enabling integrated devices.
• Radioactivity levels are up to three orders of magnitude lower than in typical ²²⁹Th-doped crystals.
• High nuclear emitter density in ²²⁹ThF₄ opens possibilities for quantum optics studies.

Conclusions:

• Physical vapour deposition of ²²⁹ThF₄ thin films offers a scalable solution for ²²⁹Th spectroscopy targets.
• This method paves the way for integrated, field-deployable solid-state nuclear clocks with reduced radioactivity.
• The developed thin films hold potential for advancing nuclear clock technology and quantum optics research.