We have incorporated a high numerical aperture spherical mirror and aspherical corrector with a barium ion trap to improve photon collection efficiency by more than an order of magnitude for generation of ion-photon entanglement.
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.