Laser cooling of a trapped particle with increased Rabi frequencies

Abstract

This paper analyses the cooling of a single particle in a harmonic trap with red-detuned laser light with fewer approximations than previously done in the literature. We avoid the adiabatic elimination of the excited atomic state but are still interested in Lamb-Dicke parameters η ≪ 1. Our results show that the Rabi frequency of the cooling laser can be chosen higher than previously assumed, thereby increasing the effective cooling rate but not affecting the final outcome of the cooling process. Since laser cooling is already a well established experimental technique, the main aim of this paper is to present a model which can be extended to more complex scenarios, like cavity-mediated laser cooling.

Sideband cooling of atoms with the help of an auxiliary transition

“…The cooling can only occurs for δ 1 < 0 and Ω 1 ≪ |δ 1 |. Actually, in the tightly confinement limit [34], the cooling rate A(−ν) = 2η 2 Ω 2 1 /γ 1 (the decay rate 2γ 1 ). It is numerically shown in [34] that the cooling rate is small.…”

“…Actually, in the tightly confinement limit [34], the cooling rate A(−ν) = 2η 2 Ω 2 1 /γ 1 (the decay rate 2γ 1 ). It is numerically shown in [34] that the cooling rate is small. Experimentally sideband cooling is realized by the well-known cooling technique described in [5], where cooling is achieved by tuning the laser to the lower sideband of the quadrupole transition, emptying the population in the upper level with another dipole transition and dissipating to metastable level through the fast dipole channel.…”

Rate-equation approach to cavity-mediated laser cooling

“…1 and 2 which has already been studied by many authors [27,28,35,36,[39][40][41][42][43][44][45][46][47]. Analogously to ordinary laser cooling [48][49][50], the effective cooling rate of cavity-mediated laser cooling scales as the Lamb-Dicke parameter η squared. A proper analysis of the cooling process using the above-mentioned master equation approach [38] hence needs to take terms up to order η 2 in * Corresponding author: pytb@leeds.ac.uk the system dynamics into account.…”

“…Proceeding as in Ref. [50], we now have a closer look at the dynamics induced by these equations. To do so, we introduce the shifted y-operator expectation values…”

“…Our calculations are analogous to the calculations presented in Refs. [48][49][50] for ordinary laser cooling. When simplifying our rate equations via adiabatic eliminations, we obtain transition rates A ± that are consistent with the results reported in Refs.…”