High-Precision Stark Effect Measurements and Laser Cooling of Lead in an Atomic Beam

Building on earlier work with trivalent thallium and indium atoms, we are pursuing the first high-precision Stark effect measurements in atomic lead, including static polarizabilities and Stark-induced amplitudes. These measurements employ precisely-calibrated high-voltage field plates in a transverse spectroscopy arrangement.  The results will complement recently completed precision measurements of transition amplitudes in lead obtained via Faraday rotation spectroscopy in quartz vapor cells¹ which were in excellent agreement with the latest ab initio lead wavefunction calculations from the Safronova group.  Here we will study both the ground state (6p²) ³P₀ – ³P₁ 1279 nm M1 transition and the excited state (6p²) ³P₁ – (6p7s) ³P₀ 368 nm E1 transition in the presence of static fields up to 20 kV/cm.  We intend to use the M1 transition to enhance the low-lying ³P₁ population for polarizability measurements, and use the E1 transition for optical cycling fluorescence detection of the ³P₁ state population for the Stark-induced amplitude measurements.

We also describe a new experiment aimed at laser cooling the atomic beam of Pb atoms. We plan to implement transverse Doppler and Sisyphus cooling by populating the long-lived ³P₁ state (as noted above) and driving the optical-cycling transition at 368 nm. Here, we will report on the generation of 368 nm light by frequency doubling a Ti:Sapph laser and progress toward initial demonstrations of optical cycling. This will establish a pathway toward ultracold Pb atoms for future precision measurements, including the possibility of assembling molecules like AuPb.

 

¹ John H. Lacy, et al., Phys. Rev. A (111), 042808 (2025).