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.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.

Jan 1, 20117 citations

An electrostatic mirror for neutral polar molecules

Steven J. Wark, G. I. Opat

An electrostatic mirror for neutral polar molecules has been constructed using an array of electrodes of alternating polarity between which a high potential was applied. This configuration produces an exponentially evanescing electric field that interacts with polar molecules by the Stark effect. The spatial gradients of the Stark energies produce forces which were used to reflect a pulsed beam of chloromethane (CH 3 Cl) molecules with a reflectivity of 25% at grazing angles of incidence of around 5 mrad. Reflections have also been produced with applied voltages as low as 100 V or with grazing angles greater than 20 mrad. This type of device could be useful for the manipulation of slow molecular beams and would permit the construction of optical elements for the de Broglie waves of molecules.An electrostatic mirror for neutral polar molecules has been constructed using an array of electrodes of alternating polarity between which a high potential was applied. This configuration produces an exponentially evanescing electric field that interacts with polar molecules by the Stark effect. The spatial gradients of the Stark energies produce forces which were used to reflect a pulsed beam of chloromethane (CH 3 Cl) molecules with a reflectivity of 25% at grazing angles of incidence of around 5 mrad. Reflections have also been produced with applied voltages as low as 100 V or with grazing angles greater than 20 mrad. This type of device could be useful for the manipulation of slow molecular beams and would permit the construction of optical elements for the de Broglie waves of molecules.

Journal of Physics B Atomic Molecular and Optical PhysicsOct 28, 199218 citations

Microstructured Switchable Mirror for Polar Molecules

Stephan A. Schulz, Hendrick L. Bethlem, Jacqueline van Veldhoven +3 more

By miniaturizing electrode geometries high electric fields can be produced using modest voltages. A planar array of $20\text{ }\ensuremath{\mu}\mathrm{m}$ wide gold electrodes, spaced $20\text{ }\ensuremath{\mu}\mathrm{m}$ apart, is made on a sapphire substrate. A voltage difference of up to 350 V is applied to adjacent electrodes, generating an electric field that decreases exponentially with distance from the substrate. This microstructured array can be used as a mirror for polar molecules and can be rapidly switched on and off. This is demonstrated by retro\penalty1000\-\allowhyphens{}reflecting a beam of state-selected ammonia molecules with a forward velocity of about $30\text{ }\text{ }\mathrm{m}/\mathrm{s}$ .By miniaturizing electrode geometries high electric fields can be produced using modest voltages. A planar array of $20\text{ }\ensuremath{\mu}\mathrm{m}$ wide gold electrodes, spaced $20\text{ }\ensuremath{\mu}\mathrm{m}$ apart, is made on a sapphire substrate. A voltage difference of up to 350 V is applied to adjacent electrodes, generating an electric field that decreases exponentially with distance from the substrate. This microstructured array can be used as a mirror for polar molecules and can be rapidly switched on and off. This is demonstrated by retro\penalty1000\-\allowhyphens{}reflecting a beam of state-selected ammonia molecules with a forward velocity of about $30\text{ }\text{ }\mathrm{m}/\mathrm{s}$.

Physical Review LettersJul 9, 200443 citations

Alternating gradient focusing and deceleration of polar molecules

Hendrick L. Bethlem, Michael R. Tarbutt, Jochen Küpper +4 more

Beams of polar molecules can be focused using an array of electrostatic lenses in alternating gradient (AG) configuration. They can also be accelerated or decelerated by applying an appropriate high-voltage switching sequence to the lenses. AG focusing is applicable to molecules in both low-field- and high-field-seeking states and is particularly well suited to the problem of decelerating heavy molecules and those in their ground rotational state. We describe the principles of AG deceleration and set out criteria to be followed in decelerator design, construction and operation. We calculate the longitudinal and transverse focusing properties of a decelerator, and exemplify this by 2D-imaging studies of a decelerated beam of metastable CO molecules.Beams of polar molecules can be focused using an array of electrostatic lenses in alternating gradient (AG) configuration. They can also be accelerated or decelerated by applying an appropriate high-voltage switching sequence to the lenses. AG focusing is applicable to molecules in both low-field- and high-field-seeking states and is particularly well suited to the problem of decelerating heavy molecules and those in their ground rotational state. We describe the principles of AG deceleration and set out criteria to be followed in decelerator design, construction and operation. We calculate the longitudinal and transverse focusing properties of a decelerator, and exemplify this by 2D-imaging studies of a decelerated beam of metastable CO molecules.

arXiv:physics/0604020Journal of Physics B Atomic Molecular and Optical PhysicsAug 8, 200686 citations

Alternate Gradient Focusing and Deceleration of a Molecular Beam

Hendrick L. Bethlem, André J. A. van Roij, Rienk T. Jongma +1 more

Neutral dipolar molecules can be decelerated and trapped using time-varying inhomogeneous electric fields. This has been demonstrated only for molecules in low-field seeking states, but can, in principle, be performed on molecules in high-field seeking states as well. Transverse stability is then much more difficult to obtain, however, since molecules in high-field seeking states always experience a force towards the electrodes. Here we demonstrate that an array of dipole lenses in alternate gradient configuration can be used to maintain transverse stability. A pulsed beam of metastable CO in high-field seeking states is accelerated from 275 to 289 m/s as well as decelerated from 275 to 260 m/s.Neutral dipolar molecules can be decelerated and trapped using time-varying inhomogeneous electric fields. This has been demonstrated only for molecules in low-field seeking states, but can, in principle, be performed on molecules in high-field seeking states as well. Transverse stability is then much more difficult to obtain, however, since molecules in high-field seeking states always experience a force towards the electrodes. Here we demonstrate that an array of dipole lenses in alternate gradient configuration can be used to maintain transverse stability. A pulsed beam of metastable CO in high-field seeking states is accelerated from 275 to 289 m/s as well as decelerated from 275 to 260 m/s.

Physical Review LettersMar 18, 2002121 citations

Focusing a fountain of neutral cesium atoms with an electrostatic lens triplet

Juris G. Kalnins, Jason Amini, Harvey Gould

An electrostatic lens with three focusing elements in an alternating-gradient configuration is used to focus a fountain of cesium atoms in their ground (strong-field-seeking) state. The lens electrodes are shaped to produce only sextupole plus dipole equipotentials which avoids adding the unnecessary nonlinear forces present in cylindrical lenses. Defocusing between lenses is greatly reduced by having all of the main electric fields point in the same direction and be of nearly equal magnitude. The addition of the third lens gave us better control of the focusing strength in the two transverse planes and allowed focusing of the beam to half the image size in both planes. The beam envelope was calculated for lens voltages selected to produced specific focusing properties. The calculations, starting from first principles, were compared with measured beam sizes and found to be in good agreement. Application to fountain experiments, atomic clocks, and focusing polar molecules in strong-field-seeking states is discussed.An electrostatic lens with three focusing elements in an alternating-gradient configuration is used to focus a fountain of cesium atoms in their ground (strong-field-seeking) state. The lens electrodes are shaped to produce only sextupole plus dipole equipotentials which avoids adding the unnecessary nonlinear forces present in cylindrical lenses. Defocusing between lenses is greatly reduced by having all of the main electric fields point in the same direction and be of nearly equal magnitude. The addition of the third lens gave us better control of the focusing strength in the two transverse planes and allowed focusing of the beam to half the image size in both planes. The beam envelope was calculated for lens voltages selected to produced specific focusing properties. The calculations, starting from first principles, were compared with measured beam sizes and found to be in good agreement. Application to fountain experiments, atomic clocks, and focusing polar molecules in strong-field-seeking states is discussed.

arXiv:physics/0603127Physical Review AOct 26, 200519 citations

30\text{ }\text{ }\mathrm{m}/\mathrm{s}