Optical clock based on ultra-cold calcium atom

Optical clock based on ultra-cold calcium atom

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A clock is a device that uses a stable oscillation pattern as a reference (i.e. pendulum, quartz). An atomic clock is a laser whose frequency is stabilised relative to a narrow optical atomic transition. Thus, the oscillator, in this case, is a trapped and isolated atom with a natural, very high oscillation rate. Thanks to this revolutionary idea and the evolution of atomic frequency and time standards have taken a giant leap forward. For nearly 100 years, the atomic frequency standard played a critical role in basic science and precision measurement. During this period, the increasing need for more precise timing and synchronisation for various applications, including navigation or tests of fundamental physics, has demanded oscillators with higher frequencies and higher performance. This paper introduces the design and instrumentation needed to build an optical reference based on an ultra-cold calcium ion that we built at our Institute of Scientific Instruments in Brno. The isolated, trapped, and laser-cooled ion has a stable oscillation rate in hundreds of terahertz. In the most recent results, we demonstrate that our frequency reference reaches the stability or instability of 5,9 parts in a quadrillion (1 followed by 16 zeros) in just a few thousand seconds. The measured full width at half maximum of the frequency stabilised clock laser is 20 Hz.

A clock is a device that uses a stable oscillation pattern as a reference (i.e. pendulum, quartz). An atomic clock is a laser whose frequency is stabilised relative to a narrow optical atomic transition. Thus, the oscillator, in this case, is a trapped and isolated atom with a natural, very high oscillation rate. Thanks to this revolutionary idea and the evolution of atomic frequency and time standards have taken a giant leap forward. For nearly 100 years, the atomic frequency standard played a critical role in basic science and precision measurement. During this period, the increasing need for more precise timing and synchronisation for various applications, including navigation or tests of fundamental physics, has demanded oscillators with higher frequencies and higher performance. This paper introduces the design and instrumentation needed to build an optical reference based on an ultra-cold calcium ion that we built at our Institute of Scientific Instruments in Brno. The isolated, trapped, and laser-cooled ion has a stable oscillation rate in hundreds of terahertz. In the most recent results, we demonstrate that our frequency reference reaches the stability or instability of 5,9 parts in a quadrillion (1 followed by 16 zeros) in just a few thousand seconds. The measured full width at half maximum of the frequency stabilised clock laser is 20 Hz.

calcium ion | laser cooling | optical clock | optical reference | Paul trap | Rabi oscillations | Ramsey oscillations

calcium ion | laser cooling | optical clock | optical reference | Paul trap | Rabi oscillations | Ramsey oscillations

01.01.2025

SPIE

9781510688087

Proceedings of SPIE the International Society for Optical Engineering

Proceedings of SPIE

13508

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