arXiv:1108.0092 · Journal of Applied Physics

Laser-induced charging of microfabricated ion traps

Shannon X. Wang, Guang Hao Low, Nathan S. Lachenmyer, Yufei Ge, Peter F. Herskind, Isaac L. Chuang

Published Nov 15, 2011• 48 citations

Abstract

Electrical charging of metal surfaces due to photoelectric generation of carriers is of concern in trapped ion quantum computation systems, due to the high sensitivity of the ions’ motional quantum states to deformation of the trapping potential. The charging induced by typical laser frequencies involved in Doppler cooling and quantum control is studied here, with microfabricated surface-electrode traps made of aluminum, copper, and gold, operated at 6 K with a single Sr+ ion trapped 100 μm above the trap surface. The lasers used are at 370, 405, 460, and 674 nm, and the typical photon flux at the trap is 1014 photons/cm2/sec. Charging is detected by monitoring the ion’s micromotion signal, which is related to the number of charges created on the trap. A wavelength and material dependence of the charging behavior is observed: Lasers at lower wavelengths cause more charging, and aluminum exhibits more charging than copper or gold. We describe the charging dynamic based on a rate-equation approach.

DOI: 10.1063/1.3662118

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