M. Zeppenfeld - Academia.edu (original) (raw)
Papers by M. Zeppenfeld
Physical Review Letters, 2011
We present a versatile electric trap for the exploration of a wide range of quantum phenomena in ... more We present a versatile electric trap for the exploration of a wide range of quantum phenomena in the interaction between polar molecules. The trap combines tunable fields, homogeneous over most of the trap volume, with steep gradient fields at the trap boundary. An initial sample of up to 10 8 CH3F molecules is trapped for as long as 60 seconds, with a 1/e storage time of 12 seconds. Adiabatic cooling down to 120 mK is achieved by slowly expanding the trap volume. The trap combines all ingredients for opto-electrical cooling, which, together with the extraordinarily long storage times, brings field-controlled quantum-mechanical collision and reaction experiments within reach.
Physical Review Letters, 2014
Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challen... more Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challenge. Here we employ a centrifugal force to produce a continuous molecular beam with a high flux at near-zero velocities. We demonstrate deceleration of three electrically guided molecular species, CH3F, CF3H, and CF3CCH, with input velocities of up to 200 m s(-1) to obtain beams with velocities below 15 m s(-1) and intensities of several 10(9) mm(-2) s(-1). The centrifuge decelerator is easy to operate and can, in principle, slow down any guidable particle. It has the potential to become a standard technique for continuous deceleration of molecules.
Physical Review A, 2009
We present an opto-electrical cooling scheme for polar molecules based on a Sisyphus-type cooling... more We present an opto-electrical cooling scheme for polar molecules based on a Sisyphus-type cooling cycle in suitably tailored electric trapping fields. Dissipation is provided by spontaneous vibrational decay in a closed level scheme found in symmetric-top rotors comprising six low-field-seeking rovibrational states. A generic trap design is presented. Suitable molecules are identified with vibrational decay rates on the order of 100 Hz. A simulation of the cooling process shows that the molecular temperature can be reduced from 1 K to 1 mK in approximately 10 s. The molecules remain electrically trapped during this time, indicating that the ultracold regime can be reached in an experimentally feasible scheme.
Physical Review A, 2010
... 24, 99 (2005). JJ Gilijamse, S. Hoekstra, SYT van de Meerakker, GC Groenenboom, and G. Meijer... more ... 24, 99 (2005). JJ Gilijamse, S. Hoekstra, SYT van de Meerakker, GC Groenenboom, and G. Meijer, Science 313, 1617 (2006). RV Krems, Phys. ... 24, 99 (2005). [6] JJ Gilijamse, S. Hoekstra, SYT van de Meerakker, GC Groenenboom, and G. Meijer, Science 313, 1617 (2006). ...
Physical Review A, 2009
... Although the molecules are produced in highly excited vi-brational states, it has been shown ... more ... Although the molecules are produced in highly excited vi-brational states, it has been shown that it is possible to trans-fer them down the vibrational ladder to create stable ultra-cold molecules 8–11 . ... pepijn.pinkse@mpq.mpg.de PHYSICAL REVIEW A 79, 013405 2009 ...
New Journal of Physics, 2010
We demonstrate Purcell-like enhancement of Rayleigh scattering into a single optical mode of a Fa... more We demonstrate Purcell-like enhancement of Rayleigh scattering into a single optical mode of a Fabry-Perot resonator for several thermal atomic and molecular gases. The light is detuned by more than an octave, in this case by hundreds of nanometers, from any optical transition, making particle excitation and spontaneous emission negligible. The enhancement of light scattering into the resonator is explained quantitatively as an interference effect of light waves emitted by a classical driven dipole oscillator. Applications of our method include the sensitive, non-destructive in-situ detection of ultracold molecules. ‡ Present address:
New Journal of Physics, 2009
High fluxes of cold polar molecules are efficiently produced by electric guiding and velocity fil... more High fluxes of cold polar molecules are efficiently produced by electric guiding and velocity filtering. Here, we investigate different aspects of the beam formation. Variations of the source parameters such as density and temperature result in characteristic changes in the guided beam. These are observed in the velocity distribution of the guided molecules as well as in the dependence of the signal of guided molecules on the trapping electric field. A model taking into account velocitydependent collisional losses of cold molecules in the region close to the nozzle accurately reproduces this behavior. This clarifies an open question on the parameter dependence of the detected signal and gives a more detailed understanding of the velocity filtering and guiding process.
Journal of Molecular Spectroscopy, 2008
Laser light at 780 nm is coupled into a resonator with a finesse of 4.5 x 105, and the output lig... more Laser light at 780 nm is coupled into a resonator with a finesse of 4.5 x 105, and the output light is detected by a photomultiplier and a camera. A part of the measured frequency spectrum of the resonator is shown in this paper. Two sets of modes are observed at distinct frequencies with the set of modes depending on
Optics express, Jan 26, 2010
A new set of vector solutions to Maxwell's equations based on solutions to the wave equation ... more A new set of vector solutions to Maxwell's equations based on solutions to the wave equation in spheroidal coordinates allows laser beams to be described beyond the paraxial approximation. Using these solutions allows us to calculate the complete first-order corrections in the short-wavelength limit to eigenmodes and eigenfrequencies in a Fabry-Perot resonator with perfectly conducting mirrors. Experimentally relevant effects are predicted. Modes which are degenerate according to the paraxial approximation are split according to their total angular momentum. This includes a splitting due to coupling between orbital angular momentum and spin angular momentum.
Physical Review Letters, 2011
We present a versatile electric trap for the exploration of a wide range of quantum phenomena in ... more We present a versatile electric trap for the exploration of a wide range of quantum phenomena in the interaction between polar molecules. The trap combines tunable fields, homogeneous over most of the trap volume, with steep gradient fields at the trap boundary. An initial sample of up to 10 8 CH3F molecules is trapped for as long as 60 seconds, with a 1/e storage time of 12 seconds. Adiabatic cooling down to 120 mK is achieved by slowly expanding the trap volume. The trap combines all ingredients for opto-electrical cooling, which, together with the extraordinarily long storage times, brings field-controlled quantum-mechanical collision and reaction experiments within reach.
Physical Review Letters, 2014
Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challen... more Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challenge. Here we employ a centrifugal force to produce a continuous molecular beam with a high flux at near-zero velocities. We demonstrate deceleration of three electrically guided molecular species, CH3F, CF3H, and CF3CCH, with input velocities of up to 200 m s(-1) to obtain beams with velocities below 15 m s(-1) and intensities of several 10(9) mm(-2) s(-1). The centrifuge decelerator is easy to operate and can, in principle, slow down any guidable particle. It has the potential to become a standard technique for continuous deceleration of molecules.
Physical Review A, 2009
We present an opto-electrical cooling scheme for polar molecules based on a Sisyphus-type cooling... more We present an opto-electrical cooling scheme for polar molecules based on a Sisyphus-type cooling cycle in suitably tailored electric trapping fields. Dissipation is provided by spontaneous vibrational decay in a closed level scheme found in symmetric-top rotors comprising six low-field-seeking rovibrational states. A generic trap design is presented. Suitable molecules are identified with vibrational decay rates on the order of 100 Hz. A simulation of the cooling process shows that the molecular temperature can be reduced from 1 K to 1 mK in approximately 10 s. The molecules remain electrically trapped during this time, indicating that the ultracold regime can be reached in an experimentally feasible scheme.
Physical Review A, 2010
... 24, 99 (2005). JJ Gilijamse, S. Hoekstra, SYT van de Meerakker, GC Groenenboom, and G. Meijer... more ... 24, 99 (2005). JJ Gilijamse, S. Hoekstra, SYT van de Meerakker, GC Groenenboom, and G. Meijer, Science 313, 1617 (2006). RV Krems, Phys. ... 24, 99 (2005). [6] JJ Gilijamse, S. Hoekstra, SYT van de Meerakker, GC Groenenboom, and G. Meijer, Science 313, 1617 (2006). ...
Physical Review A, 2009
... Although the molecules are produced in highly excited vi-brational states, it has been shown ... more ... Although the molecules are produced in highly excited vi-brational states, it has been shown that it is possible to trans-fer them down the vibrational ladder to create stable ultra-cold molecules 8–11 . ... pepijn.pinkse@mpq.mpg.de PHYSICAL REVIEW A 79, 013405 2009 ...
New Journal of Physics, 2010
We demonstrate Purcell-like enhancement of Rayleigh scattering into a single optical mode of a Fa... more We demonstrate Purcell-like enhancement of Rayleigh scattering into a single optical mode of a Fabry-Perot resonator for several thermal atomic and molecular gases. The light is detuned by more than an octave, in this case by hundreds of nanometers, from any optical transition, making particle excitation and spontaneous emission negligible. The enhancement of light scattering into the resonator is explained quantitatively as an interference effect of light waves emitted by a classical driven dipole oscillator. Applications of our method include the sensitive, non-destructive in-situ detection of ultracold molecules. ‡ Present address:
New Journal of Physics, 2009
High fluxes of cold polar molecules are efficiently produced by electric guiding and velocity fil... more High fluxes of cold polar molecules are efficiently produced by electric guiding and velocity filtering. Here, we investigate different aspects of the beam formation. Variations of the source parameters such as density and temperature result in characteristic changes in the guided beam. These are observed in the velocity distribution of the guided molecules as well as in the dependence of the signal of guided molecules on the trapping electric field. A model taking into account velocitydependent collisional losses of cold molecules in the region close to the nozzle accurately reproduces this behavior. This clarifies an open question on the parameter dependence of the detected signal and gives a more detailed understanding of the velocity filtering and guiding process.
Journal of Molecular Spectroscopy, 2008
Laser light at 780 nm is coupled into a resonator with a finesse of 4.5 x 105, and the output lig... more Laser light at 780 nm is coupled into a resonator with a finesse of 4.5 x 105, and the output light is detected by a photomultiplier and a camera. A part of the measured frequency spectrum of the resonator is shown in this paper. Two sets of modes are observed at distinct frequencies with the set of modes depending on
Optics express, Jan 26, 2010
A new set of vector solutions to Maxwell's equations based on solutions to the wave equation ... more A new set of vector solutions to Maxwell's equations based on solutions to the wave equation in spheroidal coordinates allows laser beams to be described beyond the paraxial approximation. Using these solutions allows us to calculate the complete first-order corrections in the short-wavelength limit to eigenmodes and eigenfrequencies in a Fabry-Perot resonator with perfectly conducting mirrors. Experimentally relevant effects are predicted. Modes which are degenerate according to the paraxial approximation are split according to their total angular momentum. This includes a splitting due to coupling between orbital angular momentum and spin angular momentum.