Research

The sensitivity of an atom interferometer scales with atom-light interaction time. Using freely falling atomic clouds, meters-long atomic fountains have been constructed to extend the interaction time to seconds. In contrast, atom interferometry with trapped atoms has a long interaction time in a confined space and suppressed sensitivity to vibration noise, with the potential for chip-scale atomic inertial sensors. Using an evanescent field to interact with surrounding atoms, the optical nanofiber is a promising platform for achieving atom interferometry with trapped atoms. In this project, we aim to demonstrate an atom interferometer using atoms optically trapped surrounding an optical nanofiber and use it as a precise force sensor for probing gravity on small scales.

High-performance Inertial Measurement Units (IMUs) are valuable in navigation, particularly when GPS is not accessible. Quantum IMUs based on atom interferometry can ensure short-term sensitivity and long-term stability by referencing the accuracy of the laser frequency. Still, they need to be compact and sensitive to multiple axes of the inertial frame. We are developing multiaxis atom interferometers for simultaneously measuring multiaxis accelerations and rotations. 

Gravimeters, measuring the absolute value of gravity or the gradient of the gravity field, are important tools in geoscience and civil engineering. By dropping cold wavelike atoms and forming atom interferometry, quantum gravimeters have demonstrated unprecedented precision and stability and have become one of the leading quantum sensors transferring from the laboratory to real-world applications. We are developing compact and sensitive quantum gravimeters for measuring absolute gravity and its vertical higher-order derivatives and exploring the applications of using gravimeters to study Earth's gravity model, underground water table leveling, and climate change. 

Electrical and Magnetic Field Sensing with Warm Atomic Vapors

Based on electromagnetically induced transparency or spin polarization, warm alkali atomic vapors are medium for accurate measurement of electrical and magnetic fields. These atomic sensors can find tremendous applications in neuroscience, biomedical imaging, and environmental science.

Imaging with Structured and Squeezed Light

Recent optical techniques on structured light and squeezed states of light provide new knobs for manipulating light-matter interactions. With moderate laser power safe for biological samples, microscopy and spectroscopy may go beyond the quantum noise limit.