  Quantum emitters in solids are being developed for a range of quantum
technologies, including quantum networks, computing, and sensing. However, a
remaining challenge is the poor photon collection due to the high refractive
index of most host materials. Here we overcome this limitation by introducing
monolithic parabolic reflectors as an efficient geometry for broadband photon
extraction from quantum emitter and experimentally demonstrate this device for
the nitrogen-vacancy (NV) center in diamond. Simulations indicate a photon
collection efficiency exceeding 75% across the visible spectrum and
experimental devices, fabricated using a high-throughput gray-scale lithography
process, demonstrate a photon extraction efficiency of $(48\pm 5)$%. This
device enables a raw experimental efficiency of $(12\pm 2)$\% with fluorescence
detection rates as high as $(4.6 - 5.7)\times 10^6$ counts per second from a
single NV center.
