I will give an overview of resonance fluorescence  and superradiance
, two hallmarks of quantum optics, with a focus on solid-state
implementations. The standard theory of resonance fluorescence for a
single two-level system can be extended to special artificial atoms in
the solid state, trapped in doped quantum wells whose optical
excitations are collective intersubband transitions. In this system the
modification of the Mollow triplet can be used as a measure of the
coherence time of the two-dimensional electron gas . Moreover, the
freedom in designing these devices can allow one to obtain tuneable
emission in the Terahertz range, by opening up transitions forbidden in
symmetric systems as ‘natural’ atoms . I will also present an
intuitive picture to study superradiance in presence of local
phase-breaking effects – dephasing and non-radiative emission. One can
visualise these effects with the Dicke triangle to study both the high
excitation regime and the dilute regime .
 B. R. Mollow, Power spectrum of light scattered by two-level
systems, Phys. Rev. 188, 1969 (1969).
 R. H. Dicke, Coherence in spontaneous radiation processes, Phys.
Rev. 93, 99 (1954).
 N. Shammah and S. De Liberato, Theory of intersubband resonance
fluorescence, Phys. Rev. B 92, 201402 (2015).
 N. Shammah, C. C. Phillips, and S. De Liberato, Terahertz emission
from ac Stark-split asymmetric intersubband transitions, Phys. Rev. B
89, 235309 (2014).
 N. Shammah, N. Lambert, F. Nori, and S. De Liberato, Superradiance
with local phase-breaking effects, arXiv:1704.07066 (2017).