Hybrid systems of atoms and van der Waal materials for quantum sensing

Nontechnical description Quantum sensors based on atoms can detect extremely small signals. This enables applications not possible with conventional sensors. For example, nanoscale magnetic resonance imaging (MRI) overcomes the resolution limits of conventional MRI. For small targets, signals decay rapidly with distance, making proximity essential. However, it is challenging to bring quantum sensors close to small targets while still maintaining performance. The goal of this research is to develop quantum sensors that bring atoms near external targets by containing the atoms in microscale boxes made from atomically thin materials. This approach enables atoms to be positioned within nanometers of sensing targets while preserving quantum sensing capabilities. This research has the potential to create new quantum sensors for detecting individual molecules and probing interfaces, with applications in bioelectronics, materials science, and semiconductor engineering. The project also provides interdisciplinary training at the intersection of quantum information and materials science for students at the graduate, undergraduate, and high school levels. This training helps students develop key skills relevant to the U.S. quantum and microelectronics industries. Educational activities include mentoring students through a multi-university graduate-school preparation program and developing a quantum sensing module for high school students attending a UC Irvine science summer camp. Technical description This research seeks to establish an experimental understanding of free atoms as proximal quantum sensors and as probes of electronic, photonic, and spin excitations in van der Waals quantum materials. The primary approach is to develop nanoscale atom cells in which free atoms are confined between van der Waals 2D materials. Such van der Waals atom cells have the potential to serve as nanoscale sensors that combine the homogeneity and narrow optical linewidths of free atoms with the proximity and versatility of a solid-state platform. Due to the atomically thin structure of the van der Waals materials, confined atoms can be positioned with unprecedented proximity to external sensing targets while maintaining physical and chemical separation. Atom cells are constructed within an ultrahigh vacuum apparatus, where alkali metal atoms are sealed between van der Waals materials. The cells are then characterized via confocal microscopy under applied electric and magnetic fields. The research objectives are: (1) to develop the process for fabricating microscale vacuum chambers made of van der Waals materials that confine alkali metal atoms; (2) to perform optical spectroscopy and optoelectronic studies that quantify how confinement, electrical manipulation, and contact with van der Waals quantum materials affect the trapped atoms; (3) to evaluate the capabilities of van der Waals atom cells for quantum sensing of dielectric permittivity, electric fields, and magnetic fields using DC and coherent AC approaches; and (4) to develop an approach to trap individual and isolated atoms and molecules between van der Waals layers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.