Readout scheme for solid-state nuclear clock
The low-energy excited state of the Thorium-229 (229Th) nucleus has fascinated researchers for decades. With excitation energy of only a few eV, it is the only known nuclear isomeric state accessible to laser manipulation. This system opens up many novel applications, ranging from tests of variations of the fundamental constants to technological implementations as a nuclear clock. While the exact excitation energy of the 229Th isomer remains unknown, significant progress has been made in constraining its energy in recent months. Most importantly, all recent results place the energy between 7.5 eV to 8.5 eV. This is within the transmission band of large-band-gap VUV materials such as single fluoride crystals. It becomes hence possible to embed 229Th inside a solid-state crystal and address a large number of nuclei.
This project aims to develop a readout scheme for a solid-state nuclear clock based on nuclear quadrupole resonance spectroscopy (NQRS). The interaction of the nuclear quadrupole moment with the electric field gradient of the crystal causes the splitting of the nuclear states. NQRS can be used for non-destructive readout of the nuclear state during clock operation. Moreover, the NQRS will provide valuable information about the microscopic structure of 229Th atoms doped into the crystal lattice.