Miniature trapped-ion frequency standard with ¹⁷¹Yb⁺

Abstract

We describe the development and frequency instability measurements of a highly miniaturized, buffer gas cooled, trapped-ion atomic clock. The clock utilizes the 12.6 GHz hyperfine transition of the 171 Yb + ion. A custom-built 3 cm 3 vacuum package containing the ion trap is integrated with other key elements of the atomic frequency standard, including a photo multiplier tube, miniaturized laser sources at 369 nm and 935 nm, a local oscillator, and control electronics. With the clock physics package assembled on a 10 cm x 15 cm breadboard, the long-term fractional frequency instability was measured to be 6 × 10 -14 at 25 days of integration. Later, the clock physics package was further miniaturized, and the frequency instability was measured to be 2 × 10 -11 /τ 1/2 at integration times up to 10,000 s.

F-state quenching with CH4 for buffer-gas cooled 171Y b+ frequency standard

“…For the development of a buffer-gas cooled miniature Yb + ion clock with low-power consumption 5,9 (the application motivating this work), the requirement of a laser for clearing the F-state is highly undesirable. It is favorable if the F-state can be efficiently quenched back to the ground state via a collisional process using an atom or molecule with negligible influence on the internal atomic states of the ions.…”

A Fast Algorithm for Calculation of Thêo1

“…The calculation of T k from the C (n) can be completed in O(N 2 ), so if the C (n) could all be calculated in O(N 2 ) then this would reduce the overall complexity of Thêo1 to O(N 2 ). For C (1,2) the definition is already ≤ O(N 2 ), but it can also be achieved for C (3,4) by using a recurrence relation between consecutive terms to avoid the full sum in (8) and 9:…”

“…and so C (3,4) can be calculated in the required O(N 2 ). Because the recurrence relations are for an incremented k value, the technique can only be used when calculating T k for all values of k.…”

“…Compared to the more commonly used Allan variance, Thêo1 has increased confidence at long averaging times, and can be used to estimate stability up to 50% longer averaging times. Thêo1 is also better able to identify which type of 'power-law' noise is present [2], [3]. These properties have allowed Thêo1 to be used for longrunning experiments where datasets cannot easily be extended [4].…”

Analysis of Short-Term Stability of Miniature 171Yb+ Buffer Gas Cooled Trapped Ion Clock

“…Several approaches have been pursued in the development of miniature atomic clocks in systems with a physics package smaller than 100 cm 3 . Within the context of the DARPA IMPACT program, these have included cold-atom clocks [1], [2], optical clocks [3], and trapped-ion clocks [4], [5]. All of these systems have demonstrated a short-term stability of σ y (τ ) = 1 · 10 −11 τ −1/2 .…”