68 research outputs found
A Stark decelerator on a chip
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 m about 25 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 , and about 85 cm of kinetic energy is
removed from the metastable CO molecules in this process.Comment: 17 pages, 6 figure
Sub-ppb measurement of a fundamental band rovibrational transition in HD
We report a direct measurement of the 0-1 R(0) vibrational transition
frequency in ground-state hydrogen deuteride (HD) using infrared-ultraviolet
double resonance spectroscopy in a molecular beam. Ground-state molecules are
vibrationally excited using a frequency comb referenced continuous-wave
infrared laser, and the excited molecules are detected via state-selective
ionization with a pulsed ultraviolet laser. We determine an absolute transition
frequency of 111 448 815 477(13) kHz. The 0.12 parts-per-billion (ppb)
uncertainty is limited primarily by the residual first-order Doppler shift.Comment: 5 pages, 4 figure
An electrostatic elliptical mirror for neutral polar molecules
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.Comment: 5 pages, 4 figure
Deceleration of neutral molecules in macroscopic traveling traps
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 figure
Precision spectra of A\, ^2\Sigma^+,v'=0 \leftarrow X\, ^2\Pi_{3/2},v''=0,J''=3/2 transitions in OH and OD
We report absolute optical frequencies of electronic transitions from the
X\, ^2\Pi_{3/2},v''=0,J''=3/2 rovibronic ground state to the 12 lowest levels
of the A\, ^2\Sigma^+,v'=0 vibronic state in OH, as well as to the 16
lowest levels of the same vibronic state in OD. The absolute frequencies
of these transitions have been determined with a relative uncertainty of a few
parts in , representing a 1000-fold improvement over previous
measurements. To reach this level of precision, an optical frequency comb has
been used to transfer the stability of a narrow-linewidth I-stabilized
reference laser onto the 308-nm spectroscopy laser. The comb is also used to
compare the optical frequency of the spectroscopy laser to an atomic clock
reference, providing absolute accuracy. Measurements have been carried out on
OH/OD molecules in a highly-collimated molecular beam, reducing possible
pressure shifts and minimizing Doppler broadening. Systematic shifts due to
retroreflection quality, the Zeeman effect, and the ac Stark effect have been
considered during the analysis of the measured spectra; particularly in the
case of the OD isotopologue, these effects can result in shifts of the fitted
line positions of as much as 300 kHz. The transition frequencies extracted in
the analysis were also used to determine spectroscopic constants for the A\,
^2\Sigma^+,v'=0 vibronic state. The constants fitted in this work differ
significantly from those reported in previous works that measured the
transitions, resulting in typical deviations of the predicted optical
transition frequencies of 150 MHz, but they generally agree quite well
with the constants determined using hyperfine-resolved measurements of
splittings within the state.Comment: 13 pages, 4 figure
Trapping molecules on a chip in traveling potential wells
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 m about 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. This is
experimentally demonstrated by transporting metastable CO molecules in 30 mK
deep wells that move at constant velocities above the substrate.Comment: 4 pages, 3 figure
A traveling wave decelerator for neutral polar molecules
Recently, a decelerator for neutral polar molecules has been presented that
operates on the basis of macroscopic, three-dimensional, traveling
electrostatic traps (Osterwalder et al., 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.Comment: 10 pages, 7 figure
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