Quantum optics with a cold helium beam

Atoms, unlike photons, travel at velocities readily attainable in the laboratory, making possible novel atom optical devices based on optical elements which move relative to the atomic beam. We report design studies of a device to accelerate or decelerate and simultaneously monochromatize a helium atomic beam. A helium supersonic free-jet (v equals 950 m/s, (Delta) v equals 5 m/s, FWHM) is reflected from a moving surface to produce an output beam is continuously tunable in velocity from epithermal (2000 m/s) to ultra-slow (ca. 1 m/s, De Broglie wavelength 1000 angstroms). The decelerator is highly dispersive in the low velocity regime, making the collimated ultra-slow output beam nearly monochromatic, i.e. ultra-cold. Measured properties of an actual supersonic helium free-jet expansion were used in Monte Carlo simulations of the decelerator to predict the attainable decelerated beam properties. Ultra- slow beams of usable intensity at T < 100 nK appear attainable. Finite element stress calculations for a magnetically suspended rotor verify that the necessary reflector velocities (475 m/s) can be safely achieved. Possible applications of an ultra-cold helium beam might include gas-surface scattering experiments to probe `quantum reflection' of atoms from surfaces and to measure gas- surface bound states of exceptionally low binding energy, thereby testing the contributions of retardation to the gas- surface potential.Atoms, unlike photons, travel at velocities readily attainable in the laboratory, making possible novel atom optical devices based on optical elements which move relative to the atomic beam. We report design studies of a device to accelerate or decelerate and simultaneously monochromatize a helium atomic beam. A helium supersonic free-jet (v equals 950 m/s, (Delta) v equals 5 m/s, FWHM) is reflected from a moving surface to produce an output beam is continuously tunable in velocity from epithermal (2000 m/s) to ultra-slow (ca. 1 m/s, De Broglie wavelength 1000 angstroms). The decelerator is highly dispersive in the low velocity regime, making the collimated ultra-slow output beam nearly monochromatic, i.e. ultra-cold. Measured properties of an actual supersonic helium free-jet expansion were used in Monte Carlo simulations of the decelerator to predict the attainable decelerated beam properties. Ultra- slow beams of usable intensity at T < 100 nK appear attainable. Finite element stress calculations for a magnetically suspended rotor verify that the necessary reflector velocities (475 m/s) can be safely achieved. Possible applications of an ultra-cold helium beam might include gas-surface scattering experiments to probe `quantum reflection' of atoms from surfaces and to measure gas- surface bound states of exceptionally low binding energy, thereby testing the contributions of retardation to the gas- surface potential.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEMay 1, 19972 citations

Quantum optics with cold atoms

E. Giacobino, Jean-Michel Courty, Claude Fabre +2 more

Springer eBooksDec 4, 20070 citations

Quantum optics with metastable helium atoms

Ton G. van Leeuwen, A. E. A. Koolen, M.J. de Koning +2 more

Jan 1, 20000 citations

An ultra-cold metastable helium beam for atom optics and atom physics

J.A. Swansson

Jan 1, 20060 citations

Quantum Optics and Light

S. Chua

Springer thesesJan 1, 20150 citations

Cold collisions of highly rotationally excited CO 2 with He: The prospects for cold chemistry with super-rotors

W. el-Qadi, Robert C. Forrey, Benhui Yang +2 more

Building on recent advances in ultrafast lasers and methods to slow molecules, an experiment is proposed to produce translationally cold CO ${}_{2}$ super-rotors ($j\ensuremath{\sim}200$) by combining an optical centrifuge with helium-buffer-gas cooling. Quantum mechanical calculations of the complex scattering length for He-CO ${}_{2}$ collisions demonstrate that the efficiency of rotational quenching decreases rapidly with increasing rotational excitation $j$ in the ultracold regime. Extrapolating to helium cryogenic temperatures, rotational quenching is predicted to remain inefficient up to $\ensuremath{\sim}$1 K, allowing for the possible creation of a beam of translationally cold, rotationally hot molecules.Building on recent advances in ultrafast lasers and methods to slow molecules, an experiment is proposed to produce translationally cold CO${}_{2}$ super-rotors ($j\ensuremath{\sim}200$) by combining an optical centrifuge with helium-buffer-gas cooling. Quantum mechanical calculations of the complex scattering length for He-CO${}_{2}$ collisions demonstrate that the efficiency of rotational quenching decreases rapidly with increasing rotational excitation $j$ in the ultracold regime. Extrapolating to helium cryogenic temperatures, rotational quenching is predicted to remain inefficient up to $\ensuremath{\sim}$1 K, allowing for the possible creation of a beam of translationally cold, rotationally hot molecules.

Physical Review ANov 1, 201112 citations

Building on recent advances in ultrafast lasers and methods to slow molecules, an experiment is proposed to produce translationally cold CO

{}_{2}

super-rotors ($j\ensuremath{\sim}200$) by combining an optical centrifuge with helium-buffer-gas cooling. Quantum mechanical calculations of the complex scattering length for He-CO

{}_{2}

collisions demonstrate that the efficiency of rotational quenching decreases rapidly with increasing rotational excitation

j

in the ultracold regime. Extrapolating to helium cryogenic temperatures, rotational quenching is predicted to remain inefficient up to $\ensuremath{\sim}$1 K, allowing for the possible creation of a beam of translationally cold, rotationally hot molecules.