Turquoise magic wavelength of the 87Sr clock transition -- Data set and computational notebooks

Optical lattice clocks of fermionic strontium offer a versatile platform for probing fundamental physics and developing quantum technologies. The bivalent electronic structure of strontium gives rise to a doubly forbidden atomic transition that is accessible due to hyperfine mixing in fermionic strontium-87, thus resulting in a submillihertz natural linewidth. Currently, the most accurate optical lattice clocks operate on this narrow transition by tightly trapping strontium-87 atoms in a optical lattice at 813 nm. Magic wavelengths occur where the Stark shifts of both the ground and excited states are equal, thus eliminating any position- and intensity-dependent broadening of the corresponding transition. Theoretical calculations of the electronic structure of strontium-87 have also predicted another magic wavelength of the clock transition at 497.01(57) nm. In this work, we experimentally measure the magic wavelength to be 497.4364(4) nm. Compared to the 813-nm magic wavelength, 497 nm is closer to the strong 461-nm dipolar transition of strontium, resulting in an order-of-magnitude increase in atomic polarizability and deeper traps with less optical power. The proximity to the 461-nm transition also leads to an enhanced sensitivity of 334(10) Hz/(nm E R ) at the magic wavelength.Optical lattice clocks of fermionic strontium offer a versatile platform for probing fundamental physics and developing quantum technologies. The bivalent electronic structure of strontium gives rise to a doubly forbidden atomic transition that is accessible due to hyperfine mixing in fermionic strontium-87, thus resulting in a submillihertz natural linewidth. Currently, the most accurate optical lattice clocks operate on this narrow transition by tightly trapping strontium-87 atoms in a optical lattice at 813 nm. Magic wavelengths occur where the Stark shifts of both the ground and excited states are equal, thus eliminating any position- and intensity-dependent broadening of the corresponding transition. Theoretical calculations of the electronic structure of strontium-87 have also predicted another magic wavelength of the clock transition at 497.01(57) nm. In this work, we experimentally measure the magic wavelength to be 497.4364(4) nm. Compared to the 813-nm magic wavelength, 497 nm is closer to the strong 461-nm dipolar transition of strontium, resulting in an order-of-magnitude increase in atomic polarizability and deeper traps with less optical power. The proximity to the 461-nm transition also leads to an enhanced sensitivity of 334(10) Hz/(nm E R ) at the magic wavelength.

arXiv:2506.18958Physical Review AppliedDec 22, 20250 citations

Towards a Molecular Lattice Clock: Magic-Wavelength Vibrational Spectroscopy of Sr $_{\mathrm{2}}$ Towards a Molecular Lattice Clock: Magic-Wavelength Vibrational Spectroscopy of Sr$_{\mathrm{2}}$

Kon H. Leung, Chih-Hsi Lee, Stanimir Kondov +2 more

Bulletin of the American Physical SocietyMay 29, 20180 citations

Towards a Molecular Lattice Clock: Magic-Wavelength Vibrational Spectroscopy of Sr

_{\mathrm{2}}