Quantum light excitation of Coulomb-coupled nanostructures, such as semiconductor quantum dots or light harvesting molecules, is analyzed for fixed light intensity but different photon statistics. The theory predicts a different excitation efficiency of the exciting light (thermal, coherent, and squeezed light) on the creation of optically active excitons and biexcitons. In particular, measurable differences and a strong dependence for the creation efficiency of biexcitons on the photon statistics are obtained.Quantum light excitation of Coulomb-coupled nanostructures, such as semiconductor quantum dots or light harvesting molecules, is analyzed for fixed light intensity but different photon statistics. The theory predicts a different excitation efficiency of the exciting light (thermal, coherent, and squeezed light) on the creation of optically active excitons and biexcitons. In particular, measurable differences and a strong dependence for the creation efficiency of biexcitons on the photon statistics are obtained.

Physical Review BJan 15, 200936 citations

Excitons Under the Influence of External Fields

Springer eBooksMar 6, 20070 citations

Crossover from exciton-polariton to photon Bose-Einstein condensation

Elena Kammann, Hamid Ohadi, Maria Maragkou +2 more

BEC of exciton-polaritons and related effects such as superfluidity1,2, spontaneous symmetry breaking3,4 and quantised vortices5,6 open way to creation of novel light sources7 and optical logic elements8. Remarkable observations of exciton-polariton BEC in microcavities9-12 have been reported in the recent ten years. Very recently, thermalisation and subsequent condensation of cavity photons in a dye-filled microcavity have been observed13. Here we show that BEC of both exciton-polaritons and photons can be created in the same system under different optical excitation conditions. A dynamic phase transition between a photon and a polariton BEC takes place after a single high-power excitation pulse and we find both condensed states in thermal equilibrium with the excited states. At the crossover, photons and polaritons coexist, which results in a decrease in the long-range spatial coherence. Build-up and successive depinning of polarisation is observed at the threshold of both polariton and photon condensation.BEC of exciton-polaritons and related effects such as superfluidity1,2, spontaneous symmetry breaking3,4 and quantised vortices5,6 open way to creation of novel light sources7 and optical logic elements8. Remarkable observations of exciton-polariton BEC in microcavities9-12 have been reported in the recent ten years. Very recently, thermalisation and subsequent condensation of cavity photons in a dye-filled microcavity have been observed13. Here we show that BEC of both exciton-polaritons and photons can be created in the same system under different optical excitation conditions. A dynamic phase transition between a photon and a polariton BEC takes place after a single high-power excitation pulse and we find both condensed states in thermal equilibrium with the excited states. At the crossover, photons and polaritons coexist, which results in a decrease in the long-range spatial coherence. Build-up and successive depinning of polarisation is observed at the threshold of both polariton and photon condensation.

arXiv:1103.4831Mar 24, 20111 citation

Electron beam driven collective self hybridized exciton polaritons

Parsa Darman, Maximilian Black, Prabhdeep Singh +5 more

Self-hybridized exciton polaritons in layered semiconductors emerge from the hybridization of excitonic resonances with confined photonic modes in films and provide a versatile platform for controlling light--matter interactions at the nanoscale. Yet, the nature of exciton--photon interactions and the collective and synchronous strong coupling of multiple excitons to the same photonic mode remain largely unexplored. Here, we use complementary momentum-resolved photoluminescence and cathodoluminescence spectroscopy to compare self-hybridized exciton polaritons in Ruddlesden--Popper perovskite flakes under optical and electron-beam excitation. We find that cathodoluminescence exhibits remarkably larger polaritonic level repulsion than photoluminescence, revealing an enhanced effective coupling strength under electron-beam excitation. We attribute this enhancement to the collective coherent excitation of multiple excitons by fast electrons, which couple to the same photonic mode and increase the interaction strength according to a $g_N=g_1\sqrt{N}$ scaling, with an effective number of up to $N\approx23$ coherently coupled excitonic oscillators. By reducing the electron kinetic energy, we further uncover a crossover to a partially incoherent excitation regime in which higher-order Fabry--Pérot exciton-polariton resonances disappear, leaving only the lowest polariton branches while coherent transition radiation persists. This transition arises because low-energy electrons excite excitons over extended spatial volumes, washing out the phase coherence required to sustain collective coupling and form polaritonic resonances. Our work shows that electron beams can actively modify collective light--matter coupling in layered semiconductors and establishes cathodoluminescence as a route to access excitation regimes beyond all-optical excitation schemes.Self-hybridized exciton polaritons in layered semiconductors emerge from the hybridization of excitonic resonances with confined photonic modes in films and provide a versatile platform for controlling light--matter interactions at the nanoscale. Yet, the nature of exciton--photon interactions and the collective and synchronous strong coupling of multiple excitons to the same photonic mode remain largely unexplored. Here, we use complementary momentum-resolved photoluminescence and cathodoluminescence spectroscopy to compare self-hybridized exciton polaritons in Ruddlesden--Popper perovskite flakes under optical and electron-beam excitation. We find that cathodoluminescence exhibits remarkably larger polaritonic level repulsion than photoluminescence, revealing an enhanced effective coupling strength under electron-beam excitation. We attribute this enhancement to the collective coherent excitation of multiple excitons by fast electrons, which couple to the same photonic mode and increase the interaction strength according to a $g_N=g_1\sqrt{N}$ scaling, with an effective number of up to $N\approx23$ coherently coupled excitonic oscillators. By reducing the electron kinetic energy, we further uncover a crossover to a partially incoherent excitation regime in which higher-order Fabry--Pérot exciton-polariton resonances disappear, leaving only the lowest polariton branches while coherent transition radiation persists. This transition arises because low-energy electrons excite excitons over extended spatial volumes, washing out the phase coherence required to sustain collective coupling and form polaritonic resonances. Our work shows that electron beams can actively modify collective light--matter coupling in layered semiconductors and establishes cathodoluminescence as a route to access excitation regimes beyond all-optical excitation schemes.

quant-pharXiv:2609.07164Sep 8, 2026

Excitons Under the Influence of External Fields

Springer eBooksJan 1, 20060 citations

Role of spatial dispersion in light absorption by excitons

Nail Akhmediev

Journal of Experimental and Theoretical PhysicsOct 1, 19802 citations

g_N=g_1\sqrt{N}

scaling, with an effective number of up to

N\approx23

coherently coupled excitonic oscillators. By reducing the electron kinetic energy, we further uncover a crossover to a partially incoherent excitation regime in which higher-order Fabry--Pérot exciton-polariton resonances disappear, leaving only the lowest polariton branches while coherent transition radiation persists. This transition arises because low-energy electrons excite excitons over extended spatial volumes, washing out the phase coherence required to sustain collective coupling and form polaritonic resonances. Our work shows that electron beams can actively modify collective light--matter coupling in layered semiconductors and establishes cathodoluminescence as a route to access excitation regimes beyond all-optical excitation schemes.