  The efficient excitation of quantum sources such as quantum dots or single
molecules requires high NA optics which is often a challenge in cryogenics, or
in ultrafast optics. Here we propose a 3.2 um wide parabolic mirror, with a 0.8
um focal length, fabricated by direct laser writing on CdSe/CdS colloidal
quantum dots, capable of focusing the excitation light to a sub-wavelength spot
and to extract the generated emission by collimating it into a narrow beam.
This mirror is fabricated via in-situ volumetric optical lithography, which can
be aligned to individual emitters, and it can be easily adapted to other
geometries beyond the paraboloid. This compact solid-state transducer from
far-field to the emitter has important applications in objective-free quantum
technologies.
