Chapter 3
Light–Matter Interactions for Photonic
Applications
Abstract Photonic applications of nanomaterials and quantum structures heavily
rely on light–matter interactions and effective utilisation of their remarkable optical
or optoelectronic properties. Typically, excitons in solids are coupled in one form
or another to propagating or confined electromagnetic waves, i.e. either weakly or
strongly, and interact with different kind of resonances present in their host medium.
In addition, a tailored density-of-states for the electronic or the optical system through
confinement potentials is commonly exploited to alter the coupling or dissipation
behaviours of charge carriers or photons. Moreover, hybridisation of modes can occur
which gives access to favourable properties for bosonic quasi-particles in solids.
Many of these modifications and adjustments can be harnessed in photonic devices
and fundamental studies of light–matter coupled oscillators, which can even undergo
a phase transition towards a Bose–Einstein-like condensate in a solid-state platform.
Light is shed on matter excitations in semiconductors in this chapter, with a focus
on their interactions with photonic modes and peculiarities in monolayer materials. Furthermore, cavity–polaritons are discussed with eyes towards condensation
phenomena and the influence of external fields. Particularly, polariton experiments
involving terahertz waves are motivated.
3.1 Where Strong Interactions with Light Matters
Since the discovery of cavity–polaritons in 1992 [1],
1 microcavities continuously
gained popularity amongst the quantum optics community and led to remarkable
breakthroughs with eyes toward photonic applications and the exploration of novel
physics [2–9], as they allow for the modification of the mode structure relative to
that in free space and the strong spatial confinement of photons [10–12]. The former affects the spontaneous emission rate of light emitted from a structure, as well
as its radiation pattern and direction [10, 13], whereas the latter enables a coher1 Here, one typically uses this expression when excitons (or exciton–polaritons that represent coherent exciton modes in matter) in quantum structures are coupled to an optical cavity mode.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
A. Rahimi-Iman, Semiconductor Photonics of Nanomaterials and Quantum Structures,
Springer Series in Solid-State Sciences 196,
https://doi.org/10.1007/978-3-030-69352-7_3
61
Light–Matter Interactions for Photonic
Applications
Abstract Photonic applications of nanomaterials and quantum structures heavily
rely on light–matter interactions and effective utilisation of their remarkable optical
or optoelectronic properties. Typically, excitons in solids are coupled in one form
or another to propagating or confined electromagnetic waves, i.e. either weakly or
strongly, and interact with different kind of resonances present in their host medium.
In addition, a tailored density-of-states for the electronic or the optical system through
confinement potentials is commonly exploited to alter the coupling or dissipation
behaviours of charge carriers or photons. Moreover, hybridisation of modes can occur
which gives access to favourable properties for bosonic quasi-particles in solids.
Many of these modifications and adjustments can be harnessed in photonic devices
and fundamental studies of light–matter coupled oscillators, which can even undergo
a phase transition towards a Bose–Einstein-like condensate in a solid-state platform.
Light is shed on matter excitations in semiconductors in this chapter, with a focus
on their interactions with photonic modes and peculiarities in monolayer materials. Furthermore, cavity–polaritons are discussed with eyes towards condensation
phenomena and the influence of external fields. Particularly, polariton experiments
involving terahertz waves are motivated.
3.1 Where Strong Interactions with Light Matters
Since the discovery of cavity–polaritons in 1992 [1],
1 microcavities continuously
gained popularity amongst the quantum optics community and led to remarkable
breakthroughs with eyes toward photonic applications and the exploration of novel
physics [2–9], as they allow for the modification of the mode structure relative to
that in free space and the strong spatial confinement of photons [10–12]. The former affects the spontaneous emission rate of light emitted from a structure, as well
as its radiation pattern and direction [10, 13], whereas the latter enables a coher1 Here, one typically uses this expression when excitons (or exciton–polaritons that represent coherent exciton modes in matter) in quantum structures are coupled to an optical cavity mode.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
A. Rahimi-Iman, Semiconductor Photonics of Nanomaterials and Quantum Structures,
Springer Series in Solid-State Sciences 196,
https://doi.org/10.1007/978-3-030-69352-7_3
61