Our paper "Systematic study of tunable laser cooling for trapped-ion experiments" has been published!

In this paper we apply quench cooling to a single Ytterbium ion. We study the optimal parameters for fast and deep cooling in the sideband, intermediate and semi-classical cooling regime which can be flexibly tuned via the quench laser intensity. Moreover, we discuss the non-thermal distribution of Fock states during laser cooling and reveal its impact on time dilation shifts in optical atomic clocks.

Sideband cooling of trapped ions can be further enhanced by a laser-induced increase of the natural linewidth of the cooling transition, which is referred to as “optical quenching”. The achieved effective linewidth can be fully steered via the quenching laser intensity. With this tunability at hand, we study the optimal cooling parameters in the sideband regime, intermediate regime (where the effective linewidth approx. equals the ion secular frequency) and Doppler cooling regime. We present a simulation method for the calculation of the characteristic cooling time, without the need to solve the dynamical evolution of the atomic system’s density matrix. This “tau-matrix” method significantly reduces the computational efforts of the cooling dynamics. We derive analytical expressions for the optimal Rabi frequency and minimum cooling time – to be universally used in any two-level ion. Our simulation results are benchmarked with a single ytterbium ion confined in one of our precision ion traps. In the last section of this paper we discuss the non-thermal distribution of Fock states during quench cooling and reveal its importance for time dilation shifts in optical atomic clocks.   

You can find the full paper here.