Erik Jansson

Ion traps are used for a wide range of applications from metrology to quantum simulations and quantum information processing. Microfabricated chip-based 3D ion traps are scalable to store many ions for the realization of a large number of qubits, provide deep trapping potentials compared to surface traps, and very good shielding from external electric fields. In this work, we give an overview of our recent developments on chip-based 3D ion traps. Different types of chip materials, the integration of electronic filter components on-chip and compact electrical connections in vacuum are discussed. Further, based on finite element method (FEM) simulations, we discuss how integrating micro-optics in 3D ion traps is possible without disturbing the trapped ions.

The transparent and conductive properties of indium tin oxide (ITO) thin films, make them an attractive coating for optically integrated ion traps. However, the relatively low transmittance for wavelengths $<$ 400 nm, high scattering and high production temperature limits the usability in trapped-ion-based quantum technologies. Here we present ITO coatings and a combined ITO + anti-reflective (AR) coating system optimized for an ion trap applied using ion beam sputtering (IBS). The coatings feature a high transmittance for wavelengths $<$ 400 nm and additional wavelengths up to 1000 nm, low scattering and low production temperature $<$ 150 $^{\circ}$C. The transmission, reflection and absorption spectra are simulated and the resistance, transmittance and scattering at 370 nm are measured for different ITO coating thicknesses and the ITO + AR coating system. For the ITO + AR coating system a resistance of 115 $\pm$ 5 $Ω/\Box$, transmittance of 80$\%$ and scattering of 0.012 $\pm$ 0.002$\%$ at 370 nm is achieved.

The response of matter to fields underlies the physical sciences, from particle physics to astrophysics, and from chemistry to biophysics. We observe an atom's response to an electric quadrupole field to second- and higher orders; this arises from the atom's electric quadrupole polarizability and hyperpolarizabilities. We probe a single atomic ion which is excited to Rydberg states and confined in the electric fields of a Paul trap. The quadrupolar trapping fields cause atomic energy level shifts and give rise to spectral sidebands. The observed effects are described well by theory calculations.