Advanced Ion Trap Development

Ion traps will need to be much more complex than current models for long-term quantum information applications.  While there do not seem to be fundamental limits to controlling hundreds of ions, there are a host of practical issues.  We are aggresively fabricating next-generation ion traps, including multizone structures with dozens of electrodes for the shuttling of ions through the traps with control electrical potentials.  In addition, we are fabricating ion trap structures at micron dimensions using conventional semiconductor fabrication procedures.

Microfabricated Ion Traps

One of the main hurdles in the construction of an ion trap quantum computer is scalability.  Currently, most ion traps are bulky structures which require manual alignment of the electrodes.  As traps become more complex, such an assembly technique becomes unmanageable.

In pursuing a scalable architecture, we are starting to manufacture ion traps using semiconductor-MEMS techniques.  The traps are etched from a layered gallium-arsenide/aluminum-gallium-arsenide (GaAs/AlGaAs) heterostructure.

The first successful operation of such a trap was published in Nature Physics 2, 36 (2006).  (See the links below for the manuscript, or go to group publications.)

 GaAs/AlGaAs linear ion trap electrode heterostructure fabricated at U. Maryland's Laboratory for Physical Science

Picture of four sections of GaAs/AlGaAs linear trap with electrode edges visible from scattered laser light. with Single trapped cadmium ion is visible as bright dot between electrodes.  Vertical gap is 60 microns.

1/3/06 Ions confined within an integrated semiconductor chip:

  Manuscript  

  Nature Physics News 

  U-M News Release

T-Junction Trap

Developing shuttling protocols for scalable quantum computing.

1/17/06 Two-dimensional control of individual atomic ions demonstrated in a "T"-junction ion trap array (including turning corners and swapping positions of two ions).

Applied Physics Letters manuscript, Journal Link      

Three-layer "T Junction" linear ion trap having 9 trapping zones and 49 electrodes

Movie of an ion turning corner in T-junction trap:

Movie of a two ion separation protocol:

  Composite shuttling protocol: Two ions (a and b) are trapped, then separated, ion a is shuttled around the corner, finally ion a is dumped and ion b is shuttled to the initial trap:

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