Implementing an electronic sideband offset lock for isotope shift spectroscopy in radium

Journal Article · Tue Nov 21 00:00:00 EST 2023 · Optics Express

DOI:https://doi.org/10.1364/OE.500578· OSTI ID:2217382

Rabga, T. ; Bailey, K. G.; Bishof, M. ; Booth, D. W.; Dietrich, M. R.; Greene, J. P.; Mueller, P. ; O’Connor, T. P.; Singh, J. T.

We demonstrate laser frequency stabilization with at least 6 GHz of offset tunability using an in-phase/quadrature (IQ) modulator to generate electronic sidebands (ESB) on a titanium sapphire laser at 714 nm and we apply this technique to perform isotope shift spectroscopy of ²²⁶ Ra and ²²⁵ Ra. By locking the laser to a single resonance of a high finesse optical cavity and adjusting the lock offset, we determine the frequency difference between the magneto-optical trap (MOT) transitions in the two isotopes to be 2630.0 ± 0.3 MHz, a factor of 29 more precise than the previously available data. Using the known value of the hyperfine splitting of the ³ P ₁ level, we calculate the isotope shift for the ¹ S ₀ to ³ P ₁ transition to be 2267.0 ± 2.2 MHz, a factor of 8 more precise than the best available value. Our technique could be applied to countless other atomic systems to provide unprecedented precision in isotope shift spectroscopy and other relative frequency comparisons.

• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-06CH11357; SC0019455
• OSTI ID: 2217382
• Journal Information: Optics Express, Journal Name: Optics Express Vol. 31 Journal Issue: 25; ISSN 1094-4087
• Publisher: Optical Society of America
• Country of Publication: United States
• Language: English