Light-induced atom desorption for cesium loading of a magneto-optical trap: Analysis and experimental investigations

Abstract

With the help of light-emitting diodes at the center wavelength of 470 nm, we demonstrate that light-induced atom desorption ͑LIAD͒ can be used for flexibly controlling the loading of magneto-optical traps ͑MOT͒ of cesium atoms. Under an ultralow background pressure in a quartz cell without any wall coating, we show that low intensity blue light can be used to control the loading rates ͑from 200 to 4000 atoms/s͒ and the number of cesium atoms ͑on the order of 10 4 in our experiment͒ in a MOT without the use of dispensers or any secondary atom source. A theoretical model based on an atom loading rate equation is built which can simulate the magneto-optical trap loading process with LIAD. The theoretical results are in agreement with experimental data. Some important parameters of the vacuum system are determined accordingly. The decay time of the vacuum pressure is about 70 ms, which is much shorter than the usual vacuum system for experiments on atomic ensembles. It is very difficult to measure such short times by the traditional fluorescence detection of cold atoms due to the slow loading process. The change of desorption rate ͑on the order of 10 13 atoms/ s͒ for the different desorption intensities is also determined based on the background pressure caused by noncesium atoms in the cell. According to the experimental data and theoretical calculations, we obtain a partial pressure of about 1.4ϫ 10 −10 Torr for the untrapped cesium atoms and about 6.4ϫ 10 −10 Torr for the noncesium atoms at the moment the desorption light is turned off. The system is almost an ideal vacuum system for transferring atoms into another region for further experiments.

Fast production of ultracold sodium gases using light-induced desorption and optical trapping

“…We find a pressure decay time that is much faster than the other time scales of our experiment, comparable to Refs. [46,47]. Our observations are compatible with the scenario where almost all Na atoms stick to the surfaces of the vacuum system after a few bounces when TABLE II.…”

Light-induced atom desorption from glass surfaces characterized by X-ray photoelectron spectroscopy

“…LIAD rates are linearly dependent on the light intensity, which has also been reported in Ref. [16,17]. This linear dependence indicates that the observed LIAD is a one-photon process and is not caused by heating effects.…”

“…However, most LIAD studies [13,[15][16][17][18][19] focused only on desorbed atoms, and lack of basic knowledge of the surface itself leads to a poor understanding of desorption mechanisms and also some contradictory practical information. For example, one group reported that LIAD from quartz glass is not effective [20], but another loaded a magneto-optical trap in a quartz cell by LIAD [16].Following our previous study [21], we introduce surface analysis for glass surfaces, for which LIAD measurements were then carried out by focusing on differences between vitreous silica (synthetic quartz) and commercial borosilicate glass (Pyrex), which are the most commonly used Abstract We analyzed the surfaces of vitreous silica (quartz) and borosilicate glass (Pyrex) substrates exposed to rubidium (Rb) vapor by X-ray photoelectron spectroscopy (XPS) to understand the surface conditions of alkali metal vapor cells. XPS spectra indicated that Rb atoms adopted different bonding states in quartz and Pyrex.…”

“…This phenomenon has attracted particular attention in laser cooling and trapping experiments using ultrahigh vacuum cells, into which atoms can be loaded quickly on demand from the surface by LIAD techniques [13,14]. However, most LIAD studies [13,[15][16][17][18][19] focused only on desorbed atoms, and lack of basic knowledge of the surface itself leads to a poor understanding of desorption mechanisms and also some contradictory practical information. For example, one group reported that LIAD from quartz glass is not effective [20], but another loaded a magneto-optical trap in a quartz cell by LIAD [16].…”

Elimination of the degenerate trajectory of a single atom strongly coupled to a tilted TEM10cavity mode

“…It is obvious that the cavity transmission is only dependent on the parameter y, and the trajectory of the single atom passing through the tilted TEM 10 mode thus can be determined uniquely. The experimental setup contains two important parts, including the cold atom cloud trapped by MOT [27] and the highfinesse Fabry-Pérot cavity composed of two spherical mirrors [28,29]. Both of them are located in an ultrahigh vacuum chamber.…”