Photocurrent readout and electro-optical tuning of resonantly excited exciton polaritons in a trap

Abstract

We discuss a technique to manipulate and read out strictly resonantly excited exciton polaritons confined in a three-dimensional trap. The polaritons are trapped via their photonic part in a locally elongated microcavity with a high quality factor (Q ∼ 6000), giving rise to sharp zero-dimensional resonances. Manipulation of the polaritons is achieved by spectrally tuning the quantum well excitons via the quantum confined Stark effect up to 10 meV, while the signal of the resonantly excited polaritons is simultaneously read out via the photocurrent flowing through the device. The effects of polariton-polariton interactions and interactions with the environment are revealed in the zero detuning regime by excitation power dependent investigations. By increasing the polariton number in our trap via resonant optical injection, we observe a pronounced blueshift of the lower polariton eigenenergy towards the weakly coupled cavity resonance. Furthermore, the photocurrent exhibits pronounced nonlinearities when self-tuned into resonance via its excitation dependent spectral blueshift. Exciton polaritons are fascinating bosonic quasiparticles, arising from the strong coupling between quantum well (QW) excitons and photons confined in a semiconductor microcavity. They are extremely appealing for studying the fundamentals of bosonic physics, such as Bose-Einstein condensation related effects, even at very high temperatures (up to 300 K) [1][2][3][4][5][6][7][8]. Moreover, polaritons have also been proposed to be promising candidates for the generation of single and indistinguishable photons on demand, when they are strongly confined in zerodimensional structures [9,10]. To date, most compact sources of single, indistinguishable photons are based on single quantum dots (QDs) integrated in tailored photonic environments [11]. While those systems have been optimized with respect to their efficiencies and photon interference visibilities, a fully scalable production of such devices is still a challenge due to the commonly applied randomized QD growth techniques. In contrast to semiconductor QD-microcavity systems, a polaritonic single photon source would ideally not suffer from very strong inhomogeneous broadening effects and hence could clearly outperform these existing systems in the sense of scalable realization. This would be highly beneficial for linear optics quantum information processing [12]. Indeed, the experimental realization of a system that exhibits polariton blockade (and hence generates polariton number states) would put a large number of goals in the emerging field of solid state based quantum emulation within reach. For instance, reaching the Mott insulator phase of a bosonic system, which is a key requirement to simulate quantum phase transitions [13], strongly relies on the abovementioned effects.Unfortunately, the prerequisites on the system for the observation of the required polariton quantum blockade effect are rather demanding, and conclusively the demonstration is still elusive.One important challenge ...

Superlinear increase of photocurrent due to stimulated scattering into a polariton condensate

“…Refs. [17][18][19], but in almost all cases with vertical injection; Ref. [20] also studied lateral injection, similar to our geometry, as discussed below.…”

Room-Temperature Observation of Trapped Exciton-Polariton Emission in GaN/AlGaN Microcavities with Air-Gap/III-Nitride Distributed Bragg Reflectors

“…Due to their half-light and half-matter nature, exciton-polaritons exhibit many interesting properties, such as Bose Einstein condensation (BEC), exciton-polariton lasing, − parametric amplification, , bistability, , and superfluidity . In recent years, exciton-polaritons confined laterally by potential traps have also been attracting increased attention due to their prospective applications such as bistability, , optical parametric oscillation using multiple scattering channels, − light squeezing with reduced intensity noise, single photon emitters using exciton-polariton blockade effects, − coherent exciton-polariton lasers, and polariton cascade lasers in the terahertz regime . The potential traps provide lateral photonic confinement and, to date, have been created using laser excitation, , strain modulation, , external defects or gratings, and low-dimensional microstructures which include micropillars, ,,, photonic wires, , and planar cavity region with thickness variations. − Such low-dimensional structures can be fabricated with relative ease using today’s technology, especially for III-arsenide materials.…”

Ultrastrong Light-Matter Coupling in 2D Metal-Organic Chalcogenates

“…Exciton-polaritons are part-light, part-matter quasiparticles that are the result of energy being exchanged between a photon trapped in a cavity and an exciton (Coulomb bound electron-hole pair) state that fundamentally change the optical dispersion of a system. Since exciton-polaritons are the result of strong light-matter interactions, their properties can be leveraged in optoelectronic devices such as lasers 1,2 , light-emitting diodes (LEDs) 3,4 , and photovoltaics 5,6 . The rate at which energy is exchanged between the light and matter states is described by the coupling parameter (g).…”