Absolute Frequency Measurements of the D Lines in ^{9}Be^{+} Using a Single Trapped Ion

Area of Science:

• Atomic Physics
• Quantum Optics
• Spectroscopy

Background:

• Trapped ion experiments are crucial for high-precision measurements.
• Electric dipole-allowed (E1) transitions provide valuable atomic structure information.
• Previous measurements of ^{9}Be^{+} D lines had limitations in accuracy.

Purpose of the Study:

• To measure the optical frequencies of the D line transitions in ^{9}Be^{+} with unprecedented accuracy.
• To improve the precision of atomic spectroscopy for trapped ions.
• To extract fundamental atomic parameters like fine structure splitting and hyperfine constants.

Main Methods:

• Utilized a single laser-cooled ^{9}Be^{+} ion stored in a radio frequency Paul trap.
• Employed a spectroscopy laser stabilized to an optical frequency comb.
• Referenced measurements to Coordinated Universal Time (UTC) via NIST.
• Carefully accounted for photon recoil and quantum interference effects.

Main Results:

• Achieved a relative uncertainty of Δν/ν=5×10^{-11} for the D line transitions.
• Reduced uncertainties by factors of 10 (D1) and 30 (D2) compared to prior work.
• Extracted the ^{2}P fine structure splitting (Δνfs) as 197,064.54(7) MHz.
• Determined the ^{2}P_{1/2} hyperfine constant (A P1/2) to be -117.92(4) MHz.

Conclusions:

• The study demonstrates the highest accuracy for an E1 transition in a trapped ion experiment to date.
• The enhanced precision opens new avenues for testing fundamental physics and improving atomic clocks.
• The extracted atomic parameters provide critical data for atomic structure theory.