Compatibility of Trapped Ions and Dielectrics at Cryogenic Temperatures.

We study the impact of an unshielded dielectric-here, a bare optical fiber-on a ^{40}Ca^{+} ion held several hundred microns away in a cryogenic surface electrode trap. We observe distance-dependent stray electric fields of up to a few kV/m due to the dielectric, which drift on average less than 10% per month and can be fully compensated with reasonable voltages on the trap electrodes. We observe ion motional heating rates attributable to the dielectric of ≈30 quanta per second at an ion-fiber distance of 215(4)  μm and ≈1.5  MHz motional frequency. These results demonstrate the viability of using unshielded, trap-integrated dielectric objects such as miniature optical cavities or other optical elements in cryogenic surface electrode ion traps.