The road towards polaritonic devices

Abstract

Polaritons are quasiparticles that form in semiconductors when an elementary excitation such as an exciton or a phonon interacts sufficiently strongly with light. In particular, exciton-polaritons have attracted tremendous attention for their unique properties, spanning from an ability to undergo ultra-efficient four-wave mixing to superfluidity in the condensed state. These quasiparticles possess strong intrinsic nonlinearities, while keeping most characteristics of the underlying photons. Here we review the most important features of exciton-polaritons in microcavities, with a particular emphasis on the emerging technological applications, the use of new materials for room-temperature operation, and the possibility of exploiting polaritons for quantum computation and simulation.

Plasmon-exciton-polariton lasing

“…Indeed, strong plasmon-exciton coupling has already been observed [11,13,[22][23][24][25][26][27], but earlier attempts toward achieving plasmon-exciton-polariton (PEP) lasing remained unsuccessful due to the inefficient relaxation mechanism of PEPs and the saturation of strong coupling at large pumping fluences [23]. Here, we demonstrate PEP lasing from an optically pumped array of silver nanoparticles coated by a thin layer of organic molecules at room temperature, occurring at a low threshold [8]. Strong coupling between excitons in the organic molecules and collective plasmonic resonances of the array forms PEPs.…”

“…A key early vision of the field focused around the possibility of achieving a coherent light source at low threshold powers without the need for population inversion: a polariton laser [6]. Polariton lasers have remained in the realm of proof-of-principle experiments [7,8], and their widespread usage has not yet been adopted as efforts continue to lower thresholds and optimize operating parameters. In an effort to overcome some of the material-related limitations hampering applications of exciton-polaritons, as well as to explore novel light-matter states associated with distinct types of excitons, several researchers have recently turned their attention to organic materials [9][10][11][12][13].…”

Nonclassical statistics from a polaritonic Josephson junction

“…The next milestone is the experimental demonstration of purely nonclassical effects in semiconductor microcavities [21], such as the polariton blockade [22], entanglement generation [23], nonclassical statistics [24], or the possibility to simulate quantum optics Hamiltonians [25]. Along this line, a few reports have brought initial evidence [26][27][28][29] of a quantum regime, and quantum measurements are still the focus of a number of experimental investigations [30][31][32].…”

Deployment and exploitation of nanotechnology nanomaterials and nanomedicine

“…The exploitation of the strong nonlinearities provided by the excitonic component of the polariton quasiparticles recently enabled the Advanced Photonics Group of CNR NANOTEC in Lecce (Italy) to realize the first all-optical polariton transistor-gate [59]. Further research in this field, aimed at engineering new kinds of electronic excitations with unique quantum coherence properties, long correlation both in space and time and robustness to environmentinduced decoherence may soon enable the birth of practical quantum computing systems [60].…”