Optical system for implementing accurate two-qubit gates on neutral atoms

Schemes for laser excitation of ultracold Rydberg rubidium atoms in optical dipole traps are considered for implementing two-qubit gates on neutral atoms. We discuss advantages and disadvantages of the schemes comprising objectives arranged outside a glass cell and utilising aspheric lenses placed inside a vacuum chamber. A scheme is suggested of the objective with a numerical aperture of 0.39 and flange focal length of 19 mm, which can be placed in a vacuum chamber and combined with a system of electrodes for controlling an electric field in the domain of atom interaction with laser radiation.