Evaluation of the systematic shifts of a single-40Ca+-ion frequency standard

Abstract

Progress on the evaluation of systematic frequency shifts is described in the development of the optical frequency standard based on single-trapped 40 Ca + with a "clock" transition at 729 nm. The overall systematic uncertainty of the 4s 2 S 1/2 -3d 2 D 5/2 clock resonance has been characterized to be 7.8 × 10 −16 . This uncertainty is at a level similar to the Cs fountain primary standard, while the potential stability for the 40 Ca + clock exceeds that of Cs.

Determining the structural phase transition point from the temperature of 40 Ca + Coulomb crystal

“…The 397-nm and 866-nm laser beams are overlapped and pass through the axis of the linear ion trap. Both of the lasers are stabilized by the transfer cavity technique [24] referred to an ultrastable 729-nm laser, [25] and the long-term drift is less than 1 MHz/hour. [26] The fluorescence of the ions is collected by a photomultiplier tube (PMT), while the image is captured by an electronmultiplying charge-coupled device (EMCCD).…”

Multipolar blackbody radiation shifts for single-ion clocks

“…Two of the proficiency gadgets for the optical frequency standards are with a single calcium ion ( 43 Ca + ) [30,31] trapped in a Paul trap and with a strontium ion ( 88 Sr + ) confined in an endcap trap [7,32]. The considered clock transitions in * bijaya@prl.res.in these ions are the s 1/2 → d 5/2 transitions operating in the optical regime; the principles are also similar to the proposed Ba + - [11,12], Ra + - [13,14], and Yb + -based [10,17] frequency standards.…”

Correlation between the magic wavelengths and the polarization direction of the linearly polarized laser in the Ca + optical clock

“…866 nm repumping laser 854 nm quenching laser The optical clock system consists of a 729 nm narrow line-width laser, a single ion trapping system, and a closedloop locking module, which has been described in previous work. [28][29][30][31] The 729 nm laser has a linewidth of less than 5 Hz, and the instability of the laser is 1×10 −14 for 20 s. For the ∼ 17 s feedback circle, the error due to the drift of the 729 nm probe laser for one measurement of the light shift of the clock transition can be smaller than 4 Hz, corresponding to ∼ 3 pm of the magic wavelength. The L m laser is the key element in the measurement of the magic wavelength, so the L m laser used in the experiment is frequency stabilized using a transfer cavity referenced to the 729 nm probe laser, and the long-term drift is reduced to less than 10 MHz within 4 h. An unpolarized beam splitter (BS) is used to split a part of the beam to a photodiode (PD) for monitoring the power of the L m laser, which is also shown in Fig.…”