Efficient fluorescence collection from trapped ions with an integrated spherical mirror

Efficient collection of fluorescence from trapped ions is crucial for quantum optics and quantum computing applications, specifically for qubit state detection and in generating single photons for ion-photon and remote ion entanglement. In a typical setup, only a few percent of the ion fluorescence is intercepted by the aperture of the imaging optics. We employ a simple metallic spherical mirror integrated with a linear Paul ion trap to achieve a photon collection efficiency of at least $10%$ from a single Ba⁺ ion. An aspheric corrector is used to reduce the aberrations caused by the mirror and achieve high image quality.