Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:0709.3212 · Physical Review A

Electrostatic trapping of metastable NH molecules

Steven Hoekstra, Markus Metsälä, Peter C. Zieger, Ludwig Scharfenberg, Joop J. Gilijamse, Gerard Meijer, Sebastiaan Y. T. van de Meerakker

Published Dec 27, 2007• 70 citations
arXivHTMLPDF

Abstract

We report on the Stark deceleration and electrostatic trapping of $^{14}\text{N}\text{H}$ $(a^{1}\ensuremath{\Delta})$ radicals. In the trap, the molecules are excited on the spin-forbidden $A^{3}\ensuremath{\Pi}\ensuremath{\leftarrow}a^{1}\ensuremath{\Delta}$ transition and detected via their subsequent fluorescence to the $X{^{3}\ensuremath{\Sigma}}^{\ensuremath{-}}$ ground state. The $1∕e$ trapping time is $1.4\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{s}$, from which a lower limit of 2.7 s for the radiative lifetime of the $a^{1}\ensuremath{\Delta}$, $v=0$, $J=2$ state is deduced. The spectral profile of the molecules in the trapping field is measured to probe their spatial distribution. Electrostatic trapping of metastable NH followed by optical pumping of the trapped molecules to the electronic ground state is an important step toward accumulation of these radicals in a magnetic trap.

DOI
10.1103/physreva.76.063408

Related papers

Production and deceleration of a pulsed beam of metastable NH (a1Δ) radicals

Sebastiaan Y. T. van de Meerakker, Irena Labazan, Steven Hoekstra +2 more

We report on the production of a pulsed molecular beam of metastable NH ($a ^1Δ$) radicals and present first results on the Stark deceleration of the NH ($a ^1Δ, J=2, MΩ=-4$) radicals from 550 m/s to 330 m/s. The decelerated molecules are excited on the spin-forbidden $A ^3Π\leftarrow a ^1Δ$ transition, and detected via their subsequent spontaneous fluorescence to the $X ^3Σ^{-}, v"=0$ ground-state. These experiments demonstrate the feasibility of our recently proposed scheme [Phys. Rev. A 64 (2001) 041401] to accumulate ground-state NH radicals in a magnetic trap.

arXiv:physics/0512194•Journal of Physics B Atomic Molecular and Optical Physics•Sep 25, 2006•51 citations

Accumulating NH radicals in a magnetic trap

Sebastiaan Y. T. van de Meerakker, Rienk T. Jongma, Hendrick L. Bethlem +1 more

We propose a scheme to accumulate fermionic or bosonic NH radicals ${(}^{14}\mathrm{NH}$ or ${}^{15}\mathrm{NH},$ respectively) in a magnetic trap in order to increase phase-space density. NH molecules prepared in a long-lived metastable state that exhibits a large Stark effect can be brought to a standstill using Stark deceleration. By applying an intense laser field, the NH radicals can then be forced to spontaneously decay to the electronic ground state. In the ground state the NH molecules are no longer sensitive to electric fields but show a significant Zeeman effect instead, enabling confinement and reloading of ground-state molecules in a magnetic trap.

Physical Review A•Sep 13, 2001•73 citations

Optical pumping of metastable NH radicals into the paramagnetic ground state

Sebastiaan Y. T. van de Meerakker, Boris G. Sartakov, Allard P. Mosk +2 more

We here report on the optical pumping of both ${}^{14}\mathrm{NH}$ and ${}^{15}\mathrm{NH}$ radicals from the metastable $a{}^{1}\ensuremath{\Delta}$ state into the $X{}^{3}{\ensuremath{\Sigma}}^{\ensuremath{-}}$ ground state in a molecular beam experiment. By inducing the hitherto unobserved spin-forbidden $A{}^{3}\ensuremath{\Pi}\ensuremath{\leftarrow}a{}^{1}\ensuremath{\Delta}$ transition, followed by spontaneous emission to the $X{}^{3}{\ensuremath{\Sigma}}^{\ensuremath{-}}$ state, a unidirectional pathway for population transfer from the metastable state into the electronic ground state is obtained. The optical pumping scheme demonstrated here opens up the possibility to accumulate NH radicals in a magnetic or optical trap.

Physical Review A•Sep 15, 2003•21 citations

Deceleration and Electrostatic Trapping of OH Radicals

Sebastiaan Y. T. van de Meerakker, P.H.M. Smeets, Nicolas Vanhaecke +2 more

A pulsed beam of ground state OH radicals is slowed down using a Stark decelerator and is subsequently loaded into an electrostatic trap. Characterization of the molecular beam production, deceleration, and trap loading process is performed via laser induced fluorescence detection inside the quadrupole trap. Depending on the details of the trap loading sequence, typically 10(5) OH (X2Pi(3/2),J=3/2) radicals are trapped at a density of around 10(7) cm(-3) and at temperatures in the 50-500 mK range. The 1/e trap lifetime is around 1.0 s.

arXiv:physics/0407116•Physical Review Letters•Jan 18, 2005•221 citations

STARK DECELERATION AND TRAPPING OF OH RADICALS

Sebastiaan Y. T. van de Meerakker, Nicolas Vanhaecke, Gerard Meijer

The motion of polar molecules can be controlled by time-varying inhomogeneous electric fields. In a Stark decelerator, this is exploited to accelerate, transport, or decelerate a fraction of a molecular beam. When combined with a trap, the decelerator provides a means to store the molecules for times up to seconds. Here, we review our efforts to produce cold molecules via this technique. In particular, we present a new generation Stark decelerator and electrostatic trap that selects a significant part of a molecular beam pulse that can be loaded into the trap. Deceleration and trapping experiments using a beam of OH radicals are discussed.

Annual Review of Physical Chemistry•Dec 1, 2005•90 citations

Production, Deceleration, and Detection of OH Radicals

Travis Briles

Samples of cold and ultracold polar molecules have the potential to revolutionize physical chemistry, precision measurement, and few-body quantum physics. This thesis describes experimental results for the production of cold samples of OH radicals by Stark deceleration of a supersonic beam. Since Stark deceleration cannot increase the phase space density of the sample, the initial production stage of the OH molecule is critical. The first set of experiments describes a general methodology for the production of OH beams with maximal phase space density, as well as the subsequent coupling to a Stark decelerator. Additionally, we describe the redesign of our electrostatic trap, optimized for future collision experiments of OH with co-trapped ultracold Rb atoms. The new design resulted in a 15-fold increase in total number of trapped molecules over the previous design when tested with ND3 molecules. The second set of experiments focuses on laser-based detection of OH molecules at the exit of the decelerator based on laser induced fluorescence (LIF) and resonance enhanced multiphoton ionizaton (REMPI). The latter method uses vacuum-ultraviolet light at 118nm produced by third-harmonic generation in Xe/Ar gas mixtures as the ionizing step. The sensitivity of this latter technique is limited by the attainable photon flux of the ionizing radiation at 118nm. We present detailed measurements of the conversion efficiencies as well as absolute photon fluxes. Strategies to overcome these limitations as well as prospects for detection of OH molecules in a trap are discussed.

•Jan 1, 2015•0 citations
We report on the Stark deceleration and electrostatic trapping of 14NH^{14}\text{N}\text{H}14NH (a1\ensuremathΔ)(a^{1}\ensuremath{\Delta})(a1\ensuremathΔ) radicals. In the trap, the molecules are excited on the spin-forbidden A3\ensuremathΠ\ensuremath←a1\ensuremathΔA^{3}\ensuremath{\Pi}\ensuremath{\leftarrow}a^{1}\ensuremath{\Delta}A3\ensuremathΠ\ensuremath←a1\ensuremathΔ transition and detected via their subsequent fluorescence to the X3\ensuremathΣ\ensuremath−X{^{3}\ensuremath{\Sigma}}^{\ensuremath{-}}X3\ensuremathΣ\ensuremath− ground state. The 1∕e1∕e1∕e trapping time is 1.4\ifmmode±\else\textpm\fi0.1 s1.4\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{s}1.4\ifmmode±\else\textpm\fi0.1 s, from which a lower limit of 2.7 s for the radiative lifetime of the a1\ensuremathΔa^{1}\ensuremath{\Delta}a1\ensuremathΔ, v=0v=0v=0, J=2J=2J=2 state is deduced. The spectral profile of the molecules in the trapping field is measured to probe their spatial distribution. Electrostatic trapping of metastable NH followed by optical pumping of the trapped molecules to the electronic ground state is an important step toward accumulation of these radicals in a magnetic trap.
We report on the production of a pulsed molecular beam of metastable NH (a1Δa ^1Δa1Δ) radicals and present first results on the Stark deceleration of the NH (a1Δ,J=2,MΩ=−4a ^1Δ, J=2, MΩ=-4a1Δ,J=2,MΩ=−4) radicals from 550 m/s to 330 m/s. The decelerated molecules are excited on the spin-forbidden A3Π←a1ΔA ^3Π\leftarrow a ^1ΔA3Π←a1Δ transition, and detected via their subsequent spontaneous fluorescence to the X3Σ−,v"=0X ^3Σ^{-}, v"=0X3Σ−,v"=0 ground-state. These experiments demonstrate the feasibility of our recently proposed scheme [Phys. Rev. A 64 (2001) 041401] to accumulate ground-state NH radicals in a magnetic trap.
We propose a scheme to accumulate fermionic or bosonic NH radicals (14NH{(}^{14}\mathrm{NH}(14NH or 15NH,{}^{15}\mathrm{NH},15NH, respectively) in a magnetic trap in order to increase phase-space density. NH molecules prepared in a long-lived metastable state that exhibits a large Stark effect can be brought to a standstill using Stark deceleration. By applying an intense laser field, the NH radicals can then be forced to spontaneously decay to the electronic ground state. In the ground state the NH molecules are no longer sensitive to electric fields but show a significant Zeeman effect instead, enabling confinement and reloading of ground-state molecules in a magnetic trap.
We here report on the optical pumping of both 14NH{}^{14}\mathrm{NH}14NH and 15NH{}^{15}\mathrm{NH}15NH radicals from the metastable $a{}^{1}\ensuremath{\Delta}$ state into the $X{}^{3}{\ensuremath{\Sigma}}^{\ensuremath{-}}$ ground state in a molecular beam experiment. By inducing the hitherto unobserved spin-forbidden $A{}^{3}\ensuremath{\Pi}\ensuremath{\leftarrow}a{}^{1}\ensuremath{\Delta}$ transition, followed by spontaneous emission to the $X{}^{3}{\ensuremath{\Sigma}}^{\ensuremath{-}}$ state, a unidirectional pathway for population transfer from the metastable state into the electronic ground state is obtained. The optical pumping scheme demonstrated here opens up the possibility to accumulate NH radicals in a magnetic or optical trap.
A pulsed beam of ground state OH radicals is slowed down using a Stark decelerator and is subsequently loaded into an electrostatic trap. Characterization of the molecular beam production, deceleration, and trap loading process is performed via laser induced fluorescence detection inside the quadrupole trap. Depending on the details of the trap loading sequence, typically 10(5) OH (X2Pi(3/2),J=3/2) radicals are trapped at a density of around 10(7) cm(-3) and at temperatures in the 50-500 mK range. The 1/e trap lifetime is around 1.0 s.
The motion of polar molecules can be controlled by time-varying inhomogeneous electric fields. In a Stark decelerator, this is exploited to accelerate, transport, or decelerate a fraction of a molecular beam. When combined with a trap, the decelerator provides a means to store the molecules for times up to seconds. Here, we review our efforts to produce cold molecules via this technique. In particular, we present a new generation Stark decelerator and electrostatic trap that selects a significant part of a molecular beam pulse that can be loaded into the trap. Deceleration and trapping experiments using a beam of OH radicals are discussed.
Samples of cold and ultracold polar molecules have the potential to revolutionize physical chemistry, precision measurement, and few-body quantum physics. This thesis describes experimental results for the production of cold samples of OH radicals by Stark deceleration of a supersonic beam. Since Stark deceleration cannot increase the phase space density of the sample, the initial production stage of the OH molecule is critical. The first set of experiments describes a general methodology for the production of OH beams with maximal phase space density, as well as the subsequent coupling to a Stark decelerator. Additionally, we describe the redesign of our electrostatic trap, optimized for future collision experiments of OH with co-trapped ultracold Rb atoms. The new design resulted in a 15-fold increase in total number of trapped molecules over the previous design when tested with ND3 molecules. The second set of experiments focuses on laser-based detection of OH molecules at the exit of the decelerator based on laser induced fluorescence (LIF) and resonance enhanced multiphoton ionizaton (REMPI). The latter method uses vacuum-ultraviolet light at 118nm produced by third-harmonic generation in Xe/Ar gas mixtures as the ionizing step. The sensitivity of this latter technique is limited by the attainable photon flux of the ionizing radiation at 118nm. We present detailed measurements of the conversion efficiencies as well as absolute photon fluxes. Strategies to overcome these limitations as well as prospects for detection of OH molecules in a trap are discussed.