© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

The Journal of Chemical Physics

Light desorption from an yttrium neutralizer for Rb and Fr magneto-optical trap loading

Veronica Coppolaro, Nicolò Papi, Alen Khanbekyan, C. Marinelli, E. Mariotti, Luca Marmugi, L. Moi, L. Corradi, A. Dainelli, H. Arikawa, Tetsuya Ishikawa, Y. Sakemi, R. Calabrese, G. Mazzocca, L. Tomassetti, Leonardo Ricci

Published Oct 2, 2014• 11 citations

Abstract

We present here the first evidence of photodesorption induced by low-intensity non-resonant light from an yttrium thin foil, which works as a neutralizer for Rb and Fr ions beam. Neutral atoms are suddenly ejected from the metal surface in a pulsed regime upon illumination with a broadband flash light and then released in the free volume of a pyrex cells. Here atoms are captured by a Magneto-Optical Trap (MOT), which is effectively loaded by the photodesorption. Loading times of the order of the flash rise time are measured. Desorption is also obtained in the continuous regime, by exploiting CW visible illumination of the metallic neutralizer surface. We demonstrate that at lower CW light intensities vacuum conditions are not perturbed by the photodesorption and hence the MOT dynamics remains unaffected, while the trap population increases thanks to the incoming desorbed atoms flux. Even with the Y foil at room temperature and hence with no trapped atoms, upon visible illumination, the number of trapped atoms reaches 10(5). The experimental data are then analyzed by means of an analytical rate equation model, which allows the analysis of this phenomenon and its dynamics and allows the determination of critical experimental parameters and the test of the procedure in the framework of radioactive Francium trapping. In this view, together with an extensive investigation of the phenomenon with (85)Rb, the first demonstration of the photodesorption-aided loading of a (210)Fr MOT is shown.

DOI: 10.1063/1.4896609

Related papers

Thermal surface neutralization of Fr ions with metal foils for magneto-optical trapping of radioisotopes

Hirokazu Kawamura, T. Aoki, K. Harada +7 more

We investigate neutralization processes (especially thermal surface neutralization), which are required for the magneto-optical trapping of radioactive atoms. A variety of neutralization methods are first summarized: neutral beam injection for fusion reactors, neutral atom implantation in semiconductor processing, and the production of radioactive neutral atoms in accelerators. We focus on thermal surface neutralization, which produces neutral atoms in the thermal energy range for laser cooling. The experiments were carried out with yttrium, gadolinium, and zirconium foils to neutralize francium and rubidium ions for magneto-optical trapping. The results reconfirm that yttrium foil is a good neutralizer (i.e., it has a neutral release efficiency $>65\%$). In addition, the release fraction when using yttrium foil exceeds 75\% at 1350 K, which is greater than the release fraction for the other foils. This reconfirmation is important because few previous studies have focused on thermal surface neutralization. Moreover, the results show that the neutralization efficiency is strongly influenced by the experimental process itself.

arXiv:1908.10698•Aug 28, 2019•0 citations

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

Pengfei Zhang, Gang Li, Yuchi Zhang +3 more

With the help of light-emitting diodes at the center wavelength of 470 nm, we demonstrate that light-induced atom desorption (LIAD) can be used for flexibly controlling the loading of magneto-optical traps (MOT) 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/s) and the number of cesium atoms (on the order of ${10}^{4}$ in our experiment) 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 ${10}^{13}\text{ }\text{atoms}/\text{s}$) 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 $1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\text{ }\text{Torr}$ for the untrapped cesium atoms and about $6.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\text{ }\text{Torr}$ 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.

Physical Review A•Nov 24, 2009•29 citations

Fast and efficient loading of a Rb magneto-optical trap using light-induced atomic desorption

Sergey Nikitich Atutov, R. Calabrese, V. Guidi +10 more

We have obtained fast loading of a rubidium magneto-optical trap and very high collection efficiency by capturing the atoms desorbed by a light flash from a polydimethylsiloxane film deposited on the internal surface of a cell. The atoms are trapped with an effective loading time of about 65 ms at a loading rate greater than $2\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms per second. This rate is larger than the values reported in literature and is obtained by preserving a long lifetime of the trapped atoms. This lifetime exceeds the filling time by nearly two orders of magnitude. Trap loading by light-induced desorption from siloxane compounds can be very effectively applied to store and trap a large number of atoms in the case of very weak atomic flux or extremely low vapor density. It can be also effectively used for fast production of ultracold atoms.

Physical Review A•May 22, 2003•93 citations

Investigation of dynamics of magneto-optical trap loading by light-induced atom desorption

Zhang Peng-Fei, Gang Li, Yuchi Zhang +4 more

The dynamics of magneto-optical trap loading by light-induced atom desorption (LIAD) are investigated theoretically and experimentally. The loading of the MOT has been described by a theoretical model. We have paid close attention to the background gases which are essentially important for the ultimate vacuum pressure. The experiment is done based on a glass cell and all the results are well in agreement with the theory. The decay process of the background vacuum pressure caused by the untrapped cesium atoms after shutting off the desorption light is explained quantitatively. The LIAD effect is proved to be an effective tool to control the loading of the MOT and the neutral single atoms in experiment.

Acta Physica Sinica•Jan 1, 2010•2 citations

Light induced atomic desorption from dry-film coatings

A.J. Cappello, C. de Mauro, Andrea Bogi +7 more

We report the first experimental evidence of nonthermal light induced atomic desorption (LIAD) from octadecyltrichlorosilane dry film. The experiment has been made with Rb confined in a coated cell kept at room temperature. A detailed study of the main features of LIAD effect has been made by varying intensity and wavelength of desorbing light. A discussion about the differences and similarities with other organic films that were studied first is reported. This result is important as it expands the list of materials showing such an effect and increases the possibilities to get suitable light controlled atomic sources for spectroscopy and applications. In particular, we plan to exploit this feature in a Fr magneto-optical trap apparatus.

The Journal of Chemical Physics•Jul 28, 2007•20 citations

Loading a vapor-cell magneto-optic trap using light-induced atom desorption

Brian P. Anderson, Mark A. Kasevich

Low-intensity white light was used to increase the loading rate of ${}^{87}\mathrm{Rb}$ atoms into a vapor-cell magneto-optic trap by inducing nonthermal desorption of Rb atoms from the stainless-steel walls of the vapor cell. An increased Rb partial pressure reached a new equilibrium value in fewer than 10 s after switching on the broadband light source. After the source was turned off, the partial pressure returned to its previous value in $1/e$ times as short as 10 s.

arXiv:physics/0007048•Physical Review A•Jan 12, 2001•95 citations

We present here the first evidence of photodesorption induced by low-intensity non-resonant light from an yttrium thin foil, which works as a neutralizer for Rb and Fr ions beam. Neutral atoms are suddenly ejected from the metal surface in a pulsed regime upon illumination with a broadband flash light and then released in the free volume of a pyrex cells. Here atoms are captured by a Magneto-Optical Trap (MOT), which is effectively loaded by the photodesorption. Loading times of the order of the flash rise time are measured. Desorption is also obtained in the continuous regime, by exploiting CW visible illumination of the metallic neutralizer surface. We demonstrate that at lower CW light intensities vacuum conditions are not perturbed by the photodesorption and hence the MOT dynamics remains unaffected, while the trap population increases thanks to the incoming desorbed atoms flux. Even with the Y foil at room temperature and hence with no trapped atoms, upon visible illumination, the number of trapped atoms reaches 10(5). The experimental data are then analyzed by means of an analytical rate equation model, which allows the analysis of this phenomenon and its dynamics and allows the determination of critical experimental parameters and the test of the procedure in the framework of radioactive Francium trapping. In this view, together with an extensive investigation of the phenomenon with (85)Rb, the first demonstration of the photodesorption-aided loading of a (210)Fr MOT is shown.

We investigate neutralization processes (especially thermal surface neutralization), which are required for the magneto-optical trapping of radioactive atoms. A variety of neutralization methods are first summarized: neutral beam injection for fusion reactors, neutral atom implantation in semiconductor processing, and the production of radioactive neutral atoms in accelerators. We focus on thermal surface neutralization, which produces neutral atoms in the thermal energy range for laser cooling. The experiments were carried out with yttrium, gadolinium, and zirconium foils to neutralize francium and rubidium ions for magneto-optical trapping. The results reconfirm that yttrium foil is a good neutralizer (i.e., it has a neutral release efficiency

>65\%

). In addition, the release fraction when using yttrium foil exceeds 75\% at 1350 K, which is greater than the release fraction for the other foils. This reconfirmation is important because few previous studies have focused on thermal surface neutralization. Moreover, the results show that the neutralization efficiency is strongly influenced by the experimental process itself.

With the help of light-emitting diodes at the center wavelength of 470 nm, we demonstrate that light-induced atom desorption (LIAD) can be used for flexibly controlling the loading of magneto-optical traps (MOT) 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/s) and the number of cesium atoms (on the order of

{10}^{4}

in our experiment) 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}\text{ }\text{atoms}/\text{s}

) 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 $1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\text{ }\text{Torr}$ for the untrapped cesium atoms and about $6.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\text{ }\text{Torr}$ 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.

We have obtained fast loading of a rubidium magneto-optical trap and very high collection efficiency by capturing the atoms desorbed by a light flash from a polydimethylsiloxane film deposited on the internal surface of a cell. The atoms are trapped with an effective loading time of about 65 ms at a loading rate greater than $2\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms per second. This rate is larger than the values reported in literature and is obtained by preserving a long lifetime of the trapped atoms. This lifetime exceeds the filling time by nearly two orders of magnitude. Trap loading by light-induced desorption from siloxane compounds can be very effectively applied to store and trap a large number of atoms in the case of very weak atomic flux or extremely low vapor density. It can be also effectively used for fast production of ultracold atoms.

The dynamics of magneto-optical trap loading by light-induced atom desorption (LIAD) are investigated theoretically and experimentally. The loading of the MOT has been described by a theoretical model. We have paid close attention to the background gases which are essentially important for the ultimate vacuum pressure. The experiment is done based on a glass cell and all the results are well in agreement with the theory. The decay process of the background vacuum pressure caused by the untrapped cesium atoms after shutting off the desorption light is explained quantitatively. The LIAD effect is proved to be an effective tool to control the loading of the MOT and the neutral single atoms in experiment.

We report the first experimental evidence of nonthermal light induced atomic desorption (LIAD) from octadecyltrichlorosilane dry film. The experiment has been made with Rb confined in a coated cell kept at room temperature. A detailed study of the main features of LIAD effect has been made by varying intensity and wavelength of desorbing light. A discussion about the differences and similarities with other organic films that were studied first is reported. This result is important as it expands the list of materials showing such an effect and increases the possibilities to get suitable light controlled atomic sources for spectroscopy and applications. In particular, we plan to exploit this feature in a Fr magneto-optical trap apparatus.

Low-intensity white light was used to increase the loading rate of

{10}^{13}\text{ }\text{atoms}/\text{s}

atoms into a vapor-cell magneto-optic trap by inducing nonthermal desorption of Rb atoms from the stainless-steel walls of the vapor cell. An increased Rb partial pressure reached a new equilibrium value in fewer than 10 s after switching on the broadband light source. After the source was turned off, the partial pressure returned to its previous value in

1/e

times as short as 10 s.