Recent advancements in nuclear clock technology promise to redefine precision timekeeping and open new avenues in scientific research. A study published in Nature details a breakthrough achieved by a team led by Chuankun Zhang and Eric Hudson, who successfully created ultra-thin layers of thorium-229 fluoride (ThF) using physical vapor deposition. This innovative method significantly reduces the amount of material needed, paving the way for portable designs.
Nuclear clocks, which utilize the unique low-energy nuclear transition of thorium-229, offer enhanced stability compared to traditional atomic clocks. With only about 40 grams of thorium-229 available globally, its use has been historically limited. However, the new technique allows for the creation of thin films just 30 to 100 nanometers thick, sufficient for observing the nuclear transition while minimizing material consumption.
The ability to integrate nuclear clocks into portable devices and photonic systems represents a critical step towards commercialization. Despite the progress, challenges remain, including the need to improve the efficiency of the thorium-229 nuclei involved in the transition and miniaturizing the ultraviolet lasers required for excitation.
Addressing safety concerns, the amount of thorium-229 used in these devices is minimal, significantly reducing potential risks. The radiation emitted is primarily alpha radiation, which cannot penetrate solid materials or human skin, making properly designed devices comparable in safety to existing technologies that utilize radioactive materials.
Beyond timekeeping, nuclear clocks hold the potential to facilitate groundbreaking research in physics. Theoretical physicist Victor Flambaum emphasizes their importance in exploring new physical models beyond the standard model, leveraging the nuclear energy scale that is millions of times greater than that of atomic clocks.