8.4 Manipulating and Controlling Cavity–Polaritons with Terahertz Waves
237
interactions of THz radiation and QW–microcavity systems [62–65]—yet, the envisioned THz generation has remained unachieved. Among others, THz probe experiments addressed the dark side of exciton–polariton condensates, i.e. the uncondensed
optically-dark exciton fraction in reservoir states outside the light cone [63]. Also,
THz “reset” pulses were used to manipulate the quantum state of the strongly-coupled
exciton–photon system in microcavities by disturbing the coherent energy exchange
by depopulation of 1s-excitonic polarisation [64].
On the one hand, interactions of THz waves with excitonic systems have been
widely studied and utilised in the literature [66–69]. On the other hand, control of
the polariton’s quantum state is not only achieved with THz pulses, but has been
demonstrated with optical pulses [70, 71]. However, in the author’s current polariton research project, a better understanding of how THz radiation and polaritonic
gases interact with each other, both in the linear and nonlinear regime, shall be
gained. Thereby, the way will be paved for ultrafast manipulation and control of
light–matter coupling, as well as the development of future practical THz-generation
schemes involving polariton systems. This has motivated a systematic investigation
of THz-induced effects in various configurations involving ultrafast spectroscopy
experiments and microcavity polaritons, which are envisioned in the author’s project.
The author’s aims are to directly measure Rabi oscillations using a digital holography technique for ultrafast time-resolved (TR) luminescence recordings used by
his cooperation partners [70, 71] from Lecce, Italy, and to investigate the effects of
transient THz pulses on the coherent state of the light–matter coupled system. TR-PL
studies will further give access to the dynamics of polariton condensates influenced
by the presence of pulsed THz radiation. Thereby, the effects of transient electric
fields on condensates of polaritons, which are a unique testbed for condensation
studies in solids, will be probed.
In this context, light is going to be shed on the manipulation and control of coherent
states, and the ultrafast switching between a condensed and uncondensed polariton
gas or a polaritonic and photonic regime will be explored. Consecutive investigations of the second-order temporal autocorrelation function of THz-disturbed polariton gases and condensates/superfluids will give important insights into the photon
statistics and, thereby, reveal the impact of transient external (THz) fields on the
correlations within the polariton cloud and the degree of coherence. The author is
convinced that this project will deepen the understanding of the phenomena related
to THz–exciton–polariton coupling and enhance the developments at the crossroads
of two disciplines with novel and sophisticated experiments, with the ultimate goal
of enabling further utilisation of light–matter interactions for novel optical quantum
technologies and light-source concepts.
237
interactions of THz radiation and QW–microcavity systems [62–65]—yet, the envisioned THz generation has remained unachieved. Among others, THz probe experiments addressed the dark side of exciton–polariton condensates, i.e. the uncondensed
optically-dark exciton fraction in reservoir states outside the light cone [63]. Also,
THz “reset” pulses were used to manipulate the quantum state of the strongly-coupled
exciton–photon system in microcavities by disturbing the coherent energy exchange
by depopulation of 1s-excitonic polarisation [64].
On the one hand, interactions of THz waves with excitonic systems have been
widely studied and utilised in the literature [66–69]. On the other hand, control of
the polariton’s quantum state is not only achieved with THz pulses, but has been
demonstrated with optical pulses [70, 71]. However, in the author’s current polariton research project, a better understanding of how THz radiation and polaritonic
gases interact with each other, both in the linear and nonlinear regime, shall be
gained. Thereby, the way will be paved for ultrafast manipulation and control of
light–matter coupling, as well as the development of future practical THz-generation
schemes involving polariton systems. This has motivated a systematic investigation
of THz-induced effects in various configurations involving ultrafast spectroscopy
experiments and microcavity polaritons, which are envisioned in the author’s project.
The author’s aims are to directly measure Rabi oscillations using a digital holography technique for ultrafast time-resolved (TR) luminescence recordings used by
his cooperation partners [70, 71] from Lecce, Italy, and to investigate the effects of
transient THz pulses on the coherent state of the light–matter coupled system. TR-PL
studies will further give access to the dynamics of polariton condensates influenced
by the presence of pulsed THz radiation. Thereby, the effects of transient electric
fields on condensates of polaritons, which are a unique testbed for condensation
studies in solids, will be probed.
In this context, light is going to be shed on the manipulation and control of coherent
states, and the ultrafast switching between a condensed and uncondensed polariton
gas or a polaritonic and photonic regime will be explored. Consecutive investigations of the second-order temporal autocorrelation function of THz-disturbed polariton gases and condensates/superfluids will give important insights into the photon
statistics and, thereby, reveal the impact of transient external (THz) fields on the
correlations within the polariton cloud and the degree of coherence. The author is
convinced that this project will deepen the understanding of the phenomena related
to THz–exciton–polariton coupling and enhance the developments at the crossroads
of two disciplines with novel and sophisticated experiments, with the ultimate goal
of enabling further utilisation of light–matter interactions for novel optical quantum
technologies and light-source concepts.