In a breakthrough study, researchers at the University of Paris-Saclay have successfully trapped single atoms of dysprosium (Dy), opening up new avenues for studying quantum magnetism. Optical tweezers, originally used to manipulate alkali and alkaline-Earth atoms, have now been extended to electronically complex species in the lanthanide group .
Optical tweezers work by using laser-generated electric fields to trap individual atoms. When an atom is placed within this field, it becomes polarized and moves towards the focus of the laser, where the field is strongest. The strength of the trapping potential depends on the induced dipole of the atom. However, imaging the trapped atom presents challenges. The atom’s polarizability and trapping potential vary based on its electronic state. Additionally, the imaging process typically involves the excitation of the atom, leading to detectable photon emission upon returning to the ground state. The presence of the electric field further complicates matters as it shifts the atom’s energy levels, resulting in a varying imaging transition .
To overcome these obstacles, the researchers made use of a unique property of lanthanides. The strength of the atom’s dipole induced by the laser’s electric field depends on the polarization of the laser light. By arranging a cold gas of dysprosium atoms in a five-by-five tweezer array with lasers polarized to yield the same trapping potential for both the ground and excited states of the atoms, the team successfully trapped individual dysprosium atoms in each well of the array. This was confirmed through the pattern of fluorescence observed when the trap was exposed to another beam .
The ability to trap and image lanthanide atoms opens up new possibilities for studying dipolar physics and topological states. Lanthanides possess specific properties that make them promising candidates for these investigations. By controlling them at the single-atom level, researchers can explore and exploit these unique characteristics .
Overall, this breakthrough paves the way for further exploration of quantum magnetism and offers a novel tool for studying the intricacies of lanthanide atoms. It represents a significant step forward in the field of quantum physics and provides researchers with exciting new avenues for investigation.
1. What are lanthanides?
Lanthanides are a group of metallic elements located in the f-block of the periodic table. They possess complex electronic configurations and exhibit distinctive properties, making them valuable in various scientific studies.
2. How do optical tweezers work?
Optical tweezers use laser-generated electric fields to trap and manipulate individual atoms or particles. The atoms are drawn towards the focus of the laser, where the electric field is strongest, allowing precise control over their movement.
3. What is quantum magnetism?
Quantum magnetism refers to the study of the magnetic properties and interactions of atoms or particles at the quantum level. It involves investigating phenomena arising from the quantum nature of magnetic materials.
Source:  https://physics.aps.org/articles/v16/161