Magneto-optical Trapping of Zinc Achieves Cooling Using 213.9,nm Light, Enabling High-precision Spectroscopy

The challenging task of controlling neutral atoms has taken a significant step forward with the first successful magneto-optical trapping of zinc atoms, a breakthrough achieved by Lukas Möller and Simon Stellmer at Rheinische Friedrich-Wilhelms-Universität Bonn. This research pushes the boundaries of laser cooling techniques by utilising the shortest wavelength yet demonstrated for magneto-optical trapping, enabling the capture of all stable zinc isotopes. Importantly, the team successfully trapped a fermionic isotope of zinc possessing properties that could underpin the development of a highly accurate atomic clock. This achievement represents a crucial first step towards harnessing zinc atoms for advanced applications in high-precision spectroscopy and potentially, quantum information processing.

Zinc possesses a very narrow electronic transition that makes it a promising candidate for building an optical atomic clock, a device that defines time with exceptional precision. This research characterizes the factors influencing the population and loading rate of atoms within a magneto-optical trap, a crucial first step in cooling and controlling atoms for these advanced clocks and quantum technologies.

Zinc Atom Trapping and Cooling for Clocks

Scientists are investigating zinc as a building block for the next generation of optical atomic clocks, devices that promise even greater accuracy than current standards. Optical atomic clocks are the most precise timekeepers known, with applications ranging from fundamental physics research to improved navigation systems. This research addresses the challenges of trapping and cooling zinc atoms to achieve the necessary precision for these applications, requiring the development of high-power, stable ultraviolet lasers to manipulate zinc atoms. The core technique employed is magneto-optical trapping, which uses lasers and magnetic fields to capture and cool neutral atoms.

Researchers meticulously optimized the trapping process, focusing on understanding the hyperfine structure and isotope shifts of zinc, crucial for accurate clock operation. They also considered the impact of blackbody radiation on clock accuracy and developed strategies to minimize its effects, essential for achieving a high phase-space density, a tightly packed collection of atoms, for building a high-performance clock. Successful development of a zinc-based optical clock could lead to clocks with unprecedented accuracy and stability, enabling more precise tests of fundamental physical theories, such as general relativity, and enhancing the precision of geodesy measurements, which determine the Earth’s shape and gravity field. Furthermore, zinc could serve as a building block for other quantum technologies, including quantum sensors and quantum computers.

Laser Cooling and Trapping of Atomic Zinc

Scientists have achieved a breakthrough in atomic physics by successfully laser cooling and magneto-trapping zinc atoms, marking the first demonstration of this technique with this element. This work utilizes a laser wavelength of 213. 9 nanometers, the shortest wavelength employed for magneto-optical trapping to date, and opens new avenues for high-precision spectroscopy and quantum information processing. Experiments demonstrate the ability to trap all five stable bosonic isotopes of zinc, alongside the fermionic isotope 67Zn, which possesses a narrow transition potentially suitable for building an optical atomic clock.

The team developed a sophisticated laser system capable of generating up to 130 milliwatts of power at 213. 9 nanometers through frequency quadrupling a titanium-sapphire laser. This system, stabilized using a precise locking scheme, delivers the necessary light for cooling and trapping the zinc atoms. Measurements confirm that the resulting laser beam, despite its elliptical shape, is effective for forming the six beams used in the experiment. The experimental chamber, constructed from a specialized material, incorporates a zinc oven and utilizes a magnetic gradient to confine the atoms.

Scientists carefully optimized the trapping parameters and found that ionization losses do not significantly hinder the laser cooling process. The ability to trap all stable isotopes of zinc, including the fermionic 67Zn with its hyperfine splitting, represents a significant step towards realizing novel optical clocks and quantum information processors based on this element. The successful implementation of this technique with such a short wavelength paves the way for high spatial resolution imaging and manipulation of individual atoms, crucial for advancements in neutral-atom quantum computing.

Zinc Atoms Trapped with Shortest Wavelength Laser

Scientists have successfully trapped and laser-cooled zinc atoms, marking a significant advance in atomic physics and precision measurement. This achievement utilizes a laser wavelength of 213. 9 nanometers, the shortest wavelength yet employed for magneto-optical trapping, and demonstrates the ability to trap all stable isotopes of zinc, including a fermionic isotope with properties suitable for advanced atomic clocks. The team characterized how various experimental parameters influence the number of trapped atoms and the efficiency of the trapping process, providing valuable insights for optimizing future experiments.

This work represents a crucial first step towards harnessing zinc for high-precision spectroscopy and information processing applications. The researchers determined the photoionization cross section for zinc atoms within the trap, a key parameter for understanding and mitigating atom loss. While the current setup achieves a substantial number of trapped atoms at a low temperature, photoionization currently limits the trap’s performance and lifetime. Future research will focus on improving the loading rate and trap lifetime, potentially through the addition of a specialized device to slow the atoms or a two-dimensional magneto-optical trap. Further cooling using a different laser wavelength and subsequent loading into a trap could ultimately enable detailed spectroscopic studies of the zinc clock transition, paving the way for novel atomic clock designs.