Ion trap design. (a) Simplified design of the trap. The RF, DC, and ground (G) electrodes lie on the facets of a 3D-printed substrate. All dimensions in mm. Pink text indicates electrode names. (b) Transverse cuts of the trap showing the optical clearance. The trap design provides full clearance toward the hemispherical mirror (y > 0). On the other side (y < 0), the optical clearance is slightly larger than required by the aspheric lens with NA = 0.7, corresponding to a θ = arcsin(NA) ≈ 44.4° opening angle (blue area). The RF pseudo-potential minimum, and therefore the position of the ion, is located at a distance y = 0.157 mm from the front plane of the trap.