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Rienk T. Jongma

Bio: Rienk T. Jongma is an academic researcher from Radboud University Nijmegen. The author has contributed to research in topics: Excited state & Terahertz radiation. The author has an hindex of 20, co-authored 39 publications receiving 2148 citations. Previous affiliations of Rienk T. Jongma include The Catholic University of America.

Papers
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Journal ArticleDOI
03 Aug 2000-Nature
TL;DR: The slowing of an adiabatically cooled beam of deuterated ammonia molecules by time-varying inhomogeneous electric fields and subsequent loading into an electrostatic trap is described, illustrating that polar molecules can be efficiently cooled and trapped, thus providing an opportunity to study collisions and collective quantum effects in a wide range of ultra-cold molecular systems.
Abstract: The ability to cool and slow atoms with light for subsequent trapping allows investigations of the properties and interactions of the trapped atoms in unprecedented detail. By contrast, the complex structure of molecules prohibits this type of manipulation, but magnetic trapping of calcium hydride molecules thermalized in ultra-cold buffer gas and optical trapping of caesium dimers generated from ultra-cold caesium atoms have been reported. However, these methods depend on the target molecules being paramagnetic or able to form through the association of atoms amenable to laser cooling, respectively, thus restricting the range of species that can be studied. Here we describe the slowing of an adiabatically cooled beam of deuterated ammonia molecules by time-varying inhomogeneous electric fields and subsequent loading into an electrostatic trap. We are able to trap state-selected ammonia molecules with a density of 10(6) cm(-3) in a volume of 0.25 cm3 at temperatures below 0.35 K. We observe pronounced density oscillations caused by the rapid switching of the electric fields during loading of the trap. Our findings illustrate that polar molecules can be efficiently cooled and trapped, thus providing an opportunity to study collisions and collective quantum effects in a wide range of ultra-cold molecular systems.

413 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that neutral molecules can be decelerated and trapped using a series of 64 pulsed inhomogeneous electric fields without loss in phase-space density.
Abstract: A polar molecule experiences a force in an inhomogeneous electric field. Using this force, neutral molecules can be decelerated and trapped. It is shown here that this can in principle be done without loss in phase-space density. Using a series of 64 pulsed inhomogeneous electric fields a supersonic beam of ammonia molecules ${(}^{14}{\mathrm{NH}}_{3},$ ${}^{14}{\mathrm{ND}}_{3},$ ${}^{15}{\mathrm{ND}}_{3})$ is decelerated. Subsequently, the decelerated molecules are loaded into an electrostatic quadrupole trap. Densities on the order of ${10}^{7} {\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{e}\mathrm{c}\mathrm{u}\mathrm{l}\mathrm{e}\mathrm{s}/\mathrm{c}\mathrm{m}}^{3}$ at a temperature of 25 mK are obtained for ${}^{14}{\mathrm{ND}}_{3}$ and ${}^{15}{\mathrm{ND}}_{3}$ separately and simultaneously. This corresponds to a phase-space density in the trap of $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13},$ 50 times less than the initial phase-space density in the beam.

214 citations

Journal ArticleDOI
TL;DR: A pulsed beam of ground state OH radicals is slowed down using a Stark decelerator and is subsequently loaded into an electrostatic trap and characterization of the molecular beam production, deceleration, and trap loading process is performed via laser induced fluorescence detection inside the quadrupole trap.
Abstract: 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.

210 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used cavity ring down (CRD) absorption spectroscopy in the near UV part of the spectrum for trace gas detection of small molecules and demonstrated that CRD holds great promise for sensitive (sub)‐ppb] and fast (kHz) detection of many small molecules.
Abstract: Trace gas detection of small molecules has been performed with cavity ring down (CRD) absorption spectroscopy in the near UV part of the spectrum. The absolute concentration of the OH radical present in trace amounts in heated plain air due to thermal dissociation of H2O has been calibrated as a function of temperature in the 720–1125 °C range. Detection of NH3 at the 10 ppb level is demonstrated in calibrated NH3/air flows. Detection of the background Hg concentration in plain air is performed with a current detection limit below 1 ppt. The effect of the laser linewidth in relation to the width of the absorption line is discussed in detail. Basic considerations regarding the use of CRD for trace gas detection are given and it is concluded that CRD spectroscopy holds great promise for sensitive [(sub)‐ppb] and fast (kHz) detection of many small molecules.

182 citations

Journal ArticleDOI
TL;DR: In this paper, the multi-mode structure of a short resonant cavity has been explicitly manipulated to allow a high spectral resolution, which is advantageous for the overall detection sensitivity as well.

171 citations


Cited by
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Journal ArticleDOI
TL;DR: A review of the current state of the art in the research field of cold and ultracold molecules can be found in this paper, where a discussion is based on recent experimental and theoretical work and concludes with a summary of anticipated future directions and open questions in rapidly expanding research field.
Abstract: This paper presents a review of the current state of the art in the research field of cold and ultracold molecules. It serves as an introduction to the focus issue of New Journal of Physics on Cold and Ultracold Molecules and describes new prospects for fundamental research and technological development. Cold and ultracold molecules may revolutionize physical chemistry and few-body physics, provide techniques for probing new states of quantum matter, allow for precision measurements of both fundamental and applied interest, and enable quantum simulations of condensed-matter phenomena. Ultracold molecules offer promising applications such as new platforms for quantum computing, precise control of molecular dynamics, nanolithography and Bose-enhanced chemistry. The discussion is based on recent experimental and theoretical work and concludes with a summary of anticipated future directions and open questions in this rapidly expanding research field.

1,228 citations

Journal ArticleDOI
TL;DR: A review of photo-association spectroscopy at ultracold temperatures can be found in this article, where a sampling of results including the determination of scattering lengths, their control via optical Feshbach resonances, precision determinations of atomic lifetimes from molecular spectra, limits on photoassociation rates in a Bose-Einstein condensate, and briefly, production of cold molecules.
Abstract: Photoassociation is the process in which two colliding atoms absorb a photon to form an excited molecule. The development of laser-cooling techniques for producing gases at ultracold !!1 mK" temperatures allows photoassociation spectroscopy to be performed with very high spectral resolution. Of particular interest is the investigation of molecular states whose properties can be related, with high precision, to the properties of their constituent atoms with the “complications” of chemical binding accounted for by a few parameters. These include bound long-range or purely long-range vibrational states in which two atoms spend most or all of their time at large internuclear separations. Low-energy atomic scattering states also share this characteristic. Photoassociation techniques have made important contributions to the study of all of these. This review describes what is special about photoassociation spectroscopy at ultracold temperatures, how it is performed, and a sampling of results including the determination of scattering lengths, their control via optical Feshbach resonances, precision determinations of atomic lifetimes from molecular spectra, limits on photoassociation rates in a Bose-Einstein condensate, and briefly, production of cold molecules. Discussions are illustrated with examples on alkali-metal atoms as well as other species. Progress in the field is already past the point where this review can be exhaustive, but an introduction is provided on the capabilities of photoassociation spectroscopy and the techniques presently in use.

717 citations

Journal ArticleDOI
14 Oct 2010-Nature
TL;DR: This work experimentally demonstrates laser cooling of the polar molecule strontium monofluoride (SrF) using an optical cycling scheme requiring only three lasers, and bridges the gap between ultracold (submillikelvin) temperatures and the ∼1-K temperatures attainable with directly cooled molecules.
Abstract: The development of Doppler laser cooling techniques allowed unprecedented access to ultracold temperatures of less 1 millikelvin. The motion of particles effectively ceases at such temperatures, enabling physical phenomena to be studied and controlled in extraordinary detail. Although laser cooling of atoms was demonstrated about 30 years ago, these techniques had not previously been extended to molecules. Ultracold molecules may prove even more interesting than ultracold atoms, because their greater internal complexity can potentially be exploited to investigate and manipulate a wide variety of physical phenomena, ranging from quantum information processing to chemical reactions and particle physics. Currently the only technique for producing ultracold molecules is by binding together ultracold alkali atoms to produce bi-alkali molecules. A team from Yale University now presents an experimental demonstration of laser cooling of a diatomic molecule — the polar molecule strontium monofluoride (SrF). With further refinement, the technique should enable the production of large samples of molecules at ultracold temperatures for species that are chemically distinct from bi-alkalis. Laser cooling has not yet been extended to molecules because of their complex internal structure. At present, the only technique for producing ultracold molecules is to bind ultracold alkali atoms to produce bialkali molecules. These authors experimentally demonstrate laser cooling of the polar molecule strontium monofluoride, reaching temperatures of a few millikelvin or less. The technique should allow the production of molecules at microkelvin temperatures for species that are chemically distinct from bialkalis. It has been roughly three decades since laser cooling techniques produced ultracold atoms1,2,3, leading to rapid advances in a wide array of fields. Laser cooling has not yet been extended to molecules because of their complex internal structure. However, this complexity makes molecules potentially useful for a wide range of applications4. For example, heteronuclear molecules possess permanent electric dipole moments that lead to long-range, tunable, anisotropic dipole–dipole interactions. The combination of the dipole–dipole interaction and the precise control over molecular degrees of freedom possible at ultracold temperatures makes ultracold molecules attractive candidates for use in quantum simulations of condensed-matter systems5 and in quantum computation6. Also, ultracold molecules could provide unique opportunities for studying chemical dynamics7,8 and for tests of fundamental symmetries9,10,11. Here we experimentally demonstrate laser cooling of the polar molecule strontium monofluoride (SrF). Using an optical cycling scheme requiring only three lasers12, we have observed both Sisyphus and Doppler cooling forces that reduce the transverse temperature of a SrF molecular beam substantially, to a few millikelvin or less. At present, the only technique for producing ultracold molecules is to bind together ultracold alkali atoms through Feshbach resonance13 or photoassociation14. However, proposed applications for ultracold molecules require a variety of molecular energy-level structures (for example unpaired electronic spin5,9,11,15, Omega doublets16 and so on). Our method provides an alternative route to ultracold molecules. In particular, it bridges the gap between ultracold (submillikelvin) temperatures and the ∼1-K temperatures attainable with directly cooled molecules (for example with cryogenic buffer-gas cooling17 or decelerated supersonic beams18). Ultimately, our technique should allow the production of large samples of molecules at ultracold temperatures for species that are chemically distinct from bialkalis.

703 citations

MonographDOI
01 Jan 2005

530 citations

Journal ArticleDOI
TL;DR: It is demonstrated that collisions of molecules at temperatures below 1 K can be manipulated by external electromagnetic fields and to discuss possible applications of cold controlled chemistry.
Abstract: Collisions of molecules in a thermal gas are difficult to control. Thermal motion randomizes molecular encounters and diminishes the effects of external radiation or static electromagnetic fields on intermolecular interactions. The effects of the thermal motion can be reduced by cooling molecular gases to low temperatures. At temperatures near or below 1 K, the collision energy of molecules becomes less significant than perturbations due to external fields. At the same time, inelastic scattering and chemical reactions may be very efficient in low-temperature molecular gases. The purpose of this article is to demonstrate that collisions of molecules at temperatures below 1 K can be manipulated by external electromagnetic fields and to discuss possible applications of cold controlled chemistry. The discussion focuses on molecular interactions at cold (0.001-2 K) and ultracold (<0.001 K) temperatures and is based on both recent theoretical and experimental work. The article concludes with a summary of current challenges for theory and experiment in the research of cold molecules and cold chemistry.

528 citations