Photonic “hourglass” design for efficient quantum light emission

We propose a novel “hourglass”-shaped design for highly efficient generation and collection of quantum light. The design features a quantum dot in a photonic nanowire sandwiched between tapered Bragg reflectors. For a Purcell factor of 9, the design features a spontaneous emission coupling of 0.993 to the cavity mode enabled by the strong dielectric screening of radiation modes. Thanks to a highly reflecting bottom mirror, we furthermore demonstrate a collection efficiency of 0.95 to a Gaussian profile. Finally, this photonic structure features a broad operation bandwidth, as large as 11 nm.