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.

A 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. We compare this decelerator with that of Scharfenberg et al. [Phys. Rev. A 79, 023410 (2009)] and we show that the current decelerator provides a substantially larger phase-space acceptance, even at higher acceleration. The mode of operation is described and experimentally demonstrated by guiding and decelerating CO molecules.

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.

We observe high-resolution diffraction patterns of a thermal-energy helium atom beam reflected from a microstructured surface grating at grazing incidence. The grating consists of 10-m-wide Cr strips patterned on a quartz substrate and has a periodicity of 20 m. Fully resolved diffraction peaks up to the seventh order are observed at grazing angles up to 20 mrad. With changes in de Broglie wavelength or grazing angle the relative diffraction intensities show significant variations which shed light on the nature of the atom-surface interaction potential. The observations are explained in terms of quantum reflection at the long-range attractive Casimir-van der Waals potential. DOI: 10.1103/PhysRevA.78.010902 PACS number͑s͒: 34.35.ϩa, 03.75.Be, 37.25.ϩk, 68.49.Bc Optical elements, such as mirrors and coherent beam splitters for matter waves, are prerequisites for atom and molecule interferometry. Both gratings formed by laser light and material gratings have been employed in Ramsey-Bordé and Mach-Zehnder matter-wave interferometers, respectively ͓1͔. As the de Broglie wavelengths of atoms and molecules at thermal energies are typically ഛ0.1 nm, free-standing material transmission gratings of submicrometer periodicity had to be used in interferometers for beams of Na atoms ͓2͔, dimers ͓3͔, and C 60 fullerenes ͓4,5͔. In addition, diffraction by a 100-nm-period transmission grating was applied to quantitatively determine long-range atom-surface van der Waals potentials ͓6,7͔ and to investigate small He clusters ͓8͔. Those gratings are, however, difficult to make, expensive, and fragile. Shimizu and co-workers demonstrated diffraction of ultracold atoms, released from a magneto-optical trap, by a 2-mm-period surface grating with reflective strips consisting of parallel 100-nm-wide ridges ͓9͔. Most recently, partially resolved diffraction peaks of thermal beams of metastable rare-gas atoms reflecting from a 2-m-period surface grating were reported ͓10͔.Here, we present diffraction patterns of He atom beams that are coherently reflected from a homemade 20-m-period surface grating under grazing incidence. For incident grazing angles in the milliradian range, the resulting diffraction angles are of the same order of magnitude as the ones observed with a 100-nm-period transmission grating at normal incidence ͓11͔. The projection of the grating period along the incident beam direction yields an effective grating period in the submicrometer range. Yet a 20-m-period surface grating can readily be made out of a variety of materials using standard lithographic techniques. Unlike for He atom beam scattering from smooth crystalline surfaces ͓12͔, ultrahigh vacuum and in situ surface preparation are not needed, but coherent reflection is achieved with a microscopically rough surface.We present evidence for the underlying coherent reflection mechanism being quantum reflection at the attractive long-range branch of the atom-surface interaction ͓13͔.Quantum reflection from a solid surface was observed recently with ultracold metas...

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 µm about 25 µm 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.