Efficiently loading ⁴⁰Ca⁺-²⁷Al⁺ ion crystal using sympathetic cooling and pulsed laser ablation

Area of Science:

• Atomic Physics
• Quantum Information Science
• Metrology

Background:

• Sympathetic cooling is crucial for preparing mixed-species ion crystals.
• Efficient loading of ion crystals is essential for optical clock operation.
• The aluminum-27 ion is a leading candidate for next-generation optical clocks.

Purpose of the Study:

• To demonstrate an efficient method for loading calcium-40 and aluminum-27 ion pairs.
• To reduce the loading time for sympathetic cooling of mixed-species ion crystals.
• To enhance the operational uptime of the aluminum-27 optical clock.

Main Methods:

• Utilized pulsed laser ablation for ion crystal loading.
• Employed sympathetic cooling between calcium-40 and aluminum-27 ions.
• Developed rapid detection of hot ion loading via ⁴⁰Ca⁺ narrow transition monitoring.
• Compared loading efficiency from axial and radial directions using two traps.
• Implemented adaptively controlled trap potentials to optimize loading.

Main Results:

• Achieved efficient loading of ⁴⁰Ca⁺-²⁷Al⁺ ion pairs.
• Reduced the average loading time from 26 minutes to 1 minute.
• Identified axial loading as significantly faster than radial loading.
• Demonstrated a technique for rapid detection of ion loading.

Conclusions:

• The developed method significantly accelerates the loading process for mixed-species ion crystals.
• This advancement is critical for improving the uptime of the ²⁷Al⁺ optical clock.
• The technique is broadly applicable to other mixed-species ion crystal systems utilizing sympathetic cooling.