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ABSTRACT: We demonstrate the deceleration of heavy polar molecules in low-field seeking
states by combining a cryogenic source and a travelling-wave Stark decelerator.
The cryogenic source provides a high intensity beam with low speed and
temperature, and the travelling-wave decelerator provides large deceleration
forces and high phase-space acceptance. We prove these techniques using YbF
molecules and find the experimental data to be in excellent agreement with
numerical simulations. These methods extend the scope of Stark deceleration to
a very wide range of molecules.
04/2012;
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ABSTRACT: Recently, a decelerator for neutral polar molecules has been presented that operates on the basis of macroscopic, three-dimensional, traveling electrostatic traps [A. Osterwalder, S. A. Meek, G. Hammer, H. Haak, and G. Meijer, Phys. Rev. A 81, 051401 (2010)]. In the present paper, a complete description of this decelerator is given, with emphasis on the electronics and the mechanical design. Experimental results showing the transverse velocity distributions of guided molecules are shown and compared to trajectory simulations. An assessment of non-adiabatic losses is made by comparing the deceleration signals from (13)CO with those from (12)CO and with simulated signals.
The Review of scientific instruments 09/2011; 82(9):093108. · 1.52 Impact Factor
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ABSTRACT: Focusing optics for neutral molecules finds application in shaping and steering molecular beams. Here we present an electrostatic elliptical mirror for polar molecules consisting of an array of microstructured gold electrodes deposited on a glass substrate. Alternating positive and negative voltages applied to the electrodes create a repulsive potential for molecules in low-field-seeking states. The equipotential lines are parallel to the substrate surface, which is bent in an elliptical shape. The mirror is characterized by focusing a beam of metastable CO molecules and the results are compared to the outcome of trajectory simulations.
Physical Chemistry Chemical Physics 07/2011; 13(42):18830-4. · 3.57 Impact Factor
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ABSTRACT: Focusing optics for neutral molecules finds application in shaping and
steering molecular beams. Here we present an electrostatic elliptical mirror
for polar molecules consisting of an array of microstructured gold electrodes
deposited on a glass substrate. Alternating positive and negative voltages
applied to the electrodes create a repulsive potential for molecules in
low-field-seeking states. The equipotential lines are parallel to the substrate
surface, which is bent in an elliptical shape. The mirror is characterized by
focusing a beam of metastable CO molecules and the results are compared to the
outcome of trajectory simulations.
03/2011;
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ABSTRACT: Polar molecules in selected quantum states can be guided, decelerated, and trapped using electric fields created by microstructured electrodes on a chip. Here we explore how nonadiabatic transitions between levels in which the molecules are trapped and levels in which the molecules are not trapped can be suppressed. We use 12CO and 13CO (a 3Π1,v=0) molecules, prepared in the upper Λ-doublet component of the J=1 rotational level, and study the trap loss as a function of an offset magnetic field. The experimentally observed suppression (enhancement) of the nonadiabatic transitions for 12CO (13CO) with increasing magnetic field is quantitatively explained.
Phys. Rev. A. 03/2011; 83(3).
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ABSTRACT: Polar molecules in selected quantum states can be guided, decelerated, and trapped using electric fields created by microstructured electrodes on a chip. Herein we explore how transitions between two of these quantum states can be induced while the molecules are on the chip. We use CO (a(3) Π(1) , v=0) molecules, prepared in the J=1 rotational level, and induce the J=2←J=1 rotational transition with narrow-band sub-THz (mm-wave) radiation. First, the mm-wave source is characterized using CO molecules in a freely propagating molecular beam, and both Rabi cycling and rapid adiabatic passage are examined. Then we demonstrate that the mm-wave radiation can be coupled to CO molecules that are less than 50 μm above the chip. Finally, CO molecules are guided in the J=1 level to the center of the chip where they are pumped to the J=2 level, recaptured, and guided off the chip.
ChemPhysChem 02/2011; 12(10):1799-807. · 3.41 Impact Factor
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ABSTRACT: Polar molecules in selected quantum states can be guided, decelerated and
trapped using electric fields created by microstructured electrodes on a chip.
Here we explore how non-adiabatic transitions between levels in which the
molecules are trapped and levels in which the molecules are not trapped can be
suppressed. We use 12-CO and 13-CO (a 3-Pi(1), v=0) molecules, prepared in the
upper Lambda-doublet component of the J=1 rotational level, and study the trap
loss as a function of an offset magnetic field. The experimentally observed
suppression (enhancement) of the non-adiabatic transitions for 12-CO (13-CO)
with increasing magnetic field is quantitatively explained.
01/2011;
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ABSTRACT: A new type of decelerator is presented where polar neutral molecules are guided and decelerated using the principle of traveling electric potential wells, such that molecules are confined in stable three-dimensional traps throughout. This new decelerator is superior to the best currently operational decelerator (Scharfenberg et al., Phys.Rev.A 79, 023410(2009)), providing a substantially larger acceptance even at higher accelerations. The mode of operation is described and experimentally demonstrated by guiding and decelerating CO molecules. Comment: 10 pages, 3 figures
11/2009;
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ABSTRACT: Magnetic trapping of atoms on chips has recently become straightforward, but analogous trapping of molecules has proved to be challenging. We demonstrated trapping of carbon monoxide molecules above a chip using direct loading from a supersonic beam. Upon arrival above the chip, the molecules are confined in tubular electric field traps approximately 20 micrometers in diameter, centered 25 micrometers above the chip, that move with the molecular beam at a velocity of several hundred meters per second. An array of these miniaturized moving traps is brought to a standstill over a distance of only a few centimeters. After a certain holding time, the molecules are accelerated off the chip again for detection. This loading and detection methodology is applicable to a wide variety of polar molecules, enabling the creation of a gas-phase molecular laboratory on a chip.
Science 07/2009; 324(5935):1699-702. · 31.20 Impact Factor
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ABSTRACT: A microstructured array of 1254 electrodes on a substrate has been configured to generate an array of local minima of electric field strength with a periodicity of 120 $\mu$m about 25 $\mu$m above the substrate. By applying sinusoidally varying potentials to the electrodes, these minima can be made to move smoothly along the array. Polar molecules in low-field seeking quantum states can be trapped in these traveling potential wells. Recently, we experimentally demonstrated this by transporting metastable CO molecules at constant velocities above the substrate [Phys. Rev. Lett. 100 (2008) 153003]. Here, we outline and experimentally demonstrate how this microstructured array can be used to decelerate polar molecules directly from a molecular beam. For this, the sinusoidally varying potentials need to be switched on when the molecules arrive above the chip, their frequency needs to be chirped down in time, and they need to be switched off before the molecules leave the chip again. Deceleration of metastable CO molecules from an initial velocity of 360 m/s to a final velocity as low as 240 m/s is demonstrated in the 15-35 mK deep potential wells above the 5 cm long array of electrodes. This corresponds to a deceleration of almost $10^5$ $g$, and about 85 cm$^{-1}$ of kinetic energy is removed from the metastable CO molecules in this process. Comment: 17 pages, 6 figures
12/2008;
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ABSTRACT: A microstructured array of over 1200 electrodes on a substrate has been configured to generate an array of local minima of electric field strength with a periodicity of 120 microm about 25 microm above the substrate. By applying sinusoidally varying potentials to the electrodes, these minima can be made to move smoothly along the array. Polar molecules in low field seeking quantum states can be trapped in these traveling potential wells. This is experimentally demonstrated by transporting metastable CO molecules in 30 mK deep wells that move at constant velocities above the substrate.
Physical Review Letters 04/2008; 100(15):153003. · 7.37 Impact Factor
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ABSTRACT: We present a combined experimental and theoretical study on the radiative lifetime of CO in the a (3)Pi(1,2), v=0 state. CO molecules in a beam are prepared in selected rotational levels of this metastable state, Stark-decelerated, and electrostatically trapped. From the phosphorescence decay in the trap, the radiative lifetime is measured to be 2.63+/-0.03 ms for the a (3)Pi(1), v=0, J=1 level. From the spin-orbit coupling between the a (3)Pi and the A (1)Pi states a 20% longer radiative lifetime of 3.16 ms is calculated for this level. It is concluded that coupling to other (1)Pi states contributes to the observed phosphorescence rate of metastable CO.
The Journal of Chemical Physics 01/2008; 127(22):221102. · 3.33 Impact Factor
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ABSTRACT: We present a combined experimental and theoretical study on the radiative lifetime of CO in the $a^3\Pi_{1,2}, v=0$ state. CO molecules in a beam are prepared in selected rotational levels of this metastable state, Stark-decelerated and electrostatically trapped. From the phosphorescence decay in the trap, the radiative lifetime is measured to be $2.63\pm0.03$ ms for the $a^3\Pi_1, v=0, J=1$ level. From spin-orbit coupling between the $a^3\Pi$ and the $A^1\Pi$ state a 20% longer radiative lifetime of 3.16 ms is calculated for this level. It is concluded that coupling to other $^1\Pi$ states contributes to the observed phosphorescence rate of metastable CO.
11/2007;
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ABSTRACT: The manipulation of gas-phase molecules with electric and magnetic fields above a chip is an emerging field of research. Miniaturization of the electric and magnetic field structures allows for the creation of large field gradients and tight traps above the chip. Present-day microelectronics technology enables the integration of complicated tools and devices on a compact surface area. The molecules can be positioned extremely accurately and reproducibly above the chip where they can be held isolated from their environment and where there is excellent access to them. It is expected that several of the gas-phase molecular beam experiments that are currently being done in machines that are up to several meters in length can in the future be performed on a surface area of a few cm2 and that many new experiments will become possible.
Journal of Physics: Conference Series, v.194, 012063-1-012063-8 (2009).
