We will study continuous evaporative cooling of atoms in an optical conveyor belt as a source of ultra cold atoms for a continuous Einstein-Einstein condensate (BEC) or a pumped atom laser. We will superimpose a 1-D optical lattice (OL) on a 2-D magnetic wave-guide using RF knife evaporation. This could provide a continuous source of degenerate atoms without the use of resonant photons or variable magnetic fields. Alternatively we could use a diverging optical conveyor belt with fixed optical power. The atoms would be in deep optical wells at the beginning, moving to the regime of only weak confinement in the lattice direction by the end. As the lattice walls drop, tunnelling between the lattice sites will create phase coherence across the lattice eventually leading to a continuous phase coherent stream of atoms proceeding down the magnetic wave-guide. In a second stage I will design and begin building a micro trap BEC combined with a CO2 laser OL. Such a machine would be desirable for both atom laser/atom interferometer and quantum logic applications. The optical conveyor belt and magnetic guide investigated in the first stage could be applied to this machine, providing pump atoms for a continuous atom laser on a chip. A CO2 laser OL offers the huge advantage of negligible spontaneous scattering even in deep optical traps. The atom laser could be channelled into built-in the chip interferometers, gravimeters, etc. for a new generation of sensors. The combination of an OL and microchip technology is ideal for quantum logic applications, as it is a system with huge potential for control and manipulation. The negligible spontaneous scattering with a CO2 laser yields the long coherence times required for quantum entanglement and quantum logic experiments. The large wavelength allows individual manipulation of atoms in each lattice site. Furthermore, there is the potential for multispecies exploitation with a CO2 laser OL, adding yet another degree of manipulation.
Field of science
- /natural sciences/physical sciences/optics/laser physics
- /natural sciences/physical sciences/condensed matter physics/bose-einstein condensates
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