Spectroscopy of two-dimensional quantum light sources incorporated into functional devices
Abstract
Two-dimensional materials are promising building blocks for photonic-based quantum technologies. Single-photon emitters – the required quantum light sources for
such applications – can be induced in some of these layered materials, with the prevalent example of tungsten diselenide WSe2 monolayer. They can be incorporated into
electronic and photonic devices, being combined with other atomically thin materials into tailored heterostructures and transferred onto patterned substrates. Ow ing to their intrinsic nature, these novel two-dimensional quantum systems present
a promising potential to overcome challenges such as collection efficiency limitation due to total internal reflection encountered in other solide-state sources like
semiconductor quantum dots or colour centres in diamond. This thesis undertakes
the nanofabrication and optical characterisation of two-dimensional quantum light
sources incorporated into devices.
Four projects were achieved during the PhD. They are described and discussed
in this thesis. A chapter is dedicated to an argon atmosphere glovebox system I
developed for the nanofabrication, monitoring, and characterisation of pristine two-dimensional samples is described. Second, a dichromatic pulsed laser excitation
regime is employed to coherently drive WSe2 monolayer quantum emitters incorporated into planar cavities, with a successful observation of π-pulses. Third, these
emitters are excited out-of-resonance with a continuous wave laser, and their coherence time is estimated from a Hong-Ou-Mandel interferometry experiment. A short
time of ∼ 10 ps – as compared to their ∼ ns lifetimes – is obtained; it is due to
the emitters inhomogeneous broadening. Finally, cw resonant excitation of WSe2
monolayer quantum emitters coupled to a Si3N4 waveguide is successfully achieved.