Abstract A growing number of organic materials have recently been reported to achieve room‐temperature exciton‐polariton (polariton) condensation, which is an essential requirement for practical polaritonic applications. Notably, fluorescent dyes utilizing the small‐molecule, ionic isolation lattice (SMILES) method have solved the long‐standing challenges of conventional organic dyes and have been successfully implemented in cavities to realize condensation. However, almost all demonstrations of molecular polariton condensates have inherently large spectral linewidth and poor temporal coherence arising from intrinsic disorder and low quality (Q) factor of the cavity. Here, exciton‐polaritons are realised using fluorescent dye SMILES in a high Q factor microcavity and we observe polariton condensates with a linewidth of 175 µeV. These polariton condensates exhibit temporal coherence of 30.3 ± 8.0 ps, indicating the highly coherent nature of the narrow linewidth condensates. These results set the stage for realizing highly coherent and robust polaritonic devices operating at room temperature.
more »
« less
Narrow-linewidth exciton-polariton laser
Exciton-polariton lasers are a promising source of coherent light for low-energy applications due to their low-threshold operation. However, a detailed experimental study of their spectral purity, which directly affects their coherence properties, is still missing. Here, we present a high-resolution spectroscopic investigation of the energy and linewidth of an exciton-polariton laser in the single-mode regime, which derives its coherent emission from an optically pumped and confined exciton-polariton condensate. We report an ultra-narrow linewidth of 56 MHz or 0.24 µeV, corresponding to a coherence time of 5.7 ns. The narrow linewidth is consistently achieved by using an exciton-polariton condensate with a high photonic content confined in an optically induced trap. Contrary to previous studies, we show that the excitonic reservoir created by the pump and responsible for creating the trap does not strongly affect the emission linewidth as long as the condensate is trapped and the pump power is well above the condensation (lasing) threshold. The long coherence time of the exciton-polariton system uncovered here opens up opportunities for manipulating its macroscopic quantum state, which is essential for applications in classical and quantum computing.
more »
« less
- Award ID(s):
- 2306977
- PAR ID:
- 10586730
- Publisher / Repository:
- Optica Publishing Group
- Date Published:
- Journal Name:
- Optica
- Volume:
- 11
- Issue:
- 6
- ISSN:
- 2334-2536
- Page Range / eLocation ID:
- 838
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
In recent years, quantum information science has made significant progress, leading to a multitude of quantum protocols for the most diverse applications. States carrying resources such as quantum coherence are a key component for these protocols. In this study, we optimize the quantum coherence of a nonresonantly excited exciton-polariton condensate of long living polaritons by minimizing the condensate’s interaction with the surrounding reservoir of excitons and free carriers. By combining experimental phase space data with a displaced thermal state model, we observe how quantum coherence builds up as the system is driven above the condensation threshold. Our findings demonstrate that a spatial separation between the condensate and the reservoir enhances the state’s maximum quantum coherence directly beyond the threshold. These insights pave the way for integrating polariton systems into hybrid quantum devices and advancing applications in quantum technologies.more » « less
-
ABSTRACT Exciton–polariton condensates are a promising platform for analog computation due to their macroscopic coherence and the ability to manipulate and address them optically. Patterned structures supporting these condensates further enable the realization of coherent polaritonic circuits. However, most demonstrations have relied on conventional III–V semiconductor platforms operating at cryogenic temperatures or requiring complex fabrication methods. Here, we realize molecular polariton condensate waveguides and related structures that support coherent condensate propagation at room temperature. The platform is based on a Tamm microcavity incorporating Rhodamine 3B Perchlorate embedded in a small‐molecule ionic isolation lattice (SMILES) complex as the excitonic medium, with photonic structures defined by focused ion beam milling. Spatial and momentum‐resolved photoluminescence measurements reveal room‐temperature propagation of polariton condensates in patterned waveguides. We further investigate the condensate blueshift and finite momentum, demonstrating that the condensate remains strongly confined during propagation. As a proof of concept, we also demonstrate condensation in custom geometries, including ring waveguides, Y‐splitters, and a Mach–Zehnder interferometer. These results establish a versatile platform for the rapid prototyping of polaritonic devices and represent an important step toward complex fully integrated polaritonic circuits operating at room temperature.more » « less
-
An indirect exciton (IX), also known as an interlayer exciton, is a bound pair of an electron and a hole confined in spatially separated layers. Due to their long lifetimes, IXs can cool below the temperature of quantum degeneracy. This provides an opportunity to experimentally study cold composite bosons. This article overviews our studies of cold IXs, presenting spontaneous coherence and Bose–Einstein condensation of IXs and phenomena observed in the IX condensate, including the spatially ordered exciton state, commensurability effect of exciton density wave, spin textures, Pancharatnam–Berry phase, long-range coherent spin transport, and interference dislocations.more » « less
-
The condensation of half-light half-matter exciton polaritons in semiconductor optical cavities is a striking example of macroscopic quantum coherence in a solid-state platform. Quantum coherence is possible only when there are strong interactions between the exciton polaritons provided by their excitonic constituents. Rydberg excitons with high principal value exhibit strong dipole–dipole interactions in cold atoms. However, polaritons with the excitonic constituent that is an excited state, namely Rydberg exciton polaritons (REPs), have not yet been experimentally observed. Here, we observe the formation of REPs in a single crystal CsPbBr 3 perovskite cavity without any external fields. These polaritons exhibit strong nonlinear behavior that leads to a coherent polariton condensate with a prominent blue shift. Furthermore, the REPs in CsPbBr 3 are highly anisotropic and have a large extinction ratio, arising from the perovskite’s orthorhombic crystal structure. Our observation not only sheds light on the importance of many-body physics in coherent polariton systems involving higher-order excited states, but also paves the way for exploring these coherent interactions for solid-state quantum optical information processing.more » « less
An official website of the United States government

