Light-controlled bright and stable plexcitonic quantum emitters operating in both single-photon and entangled-photon-pair emission modes

Project Information

QESPEM

Grant agreement ID: 101025664

DOI

10.3030/101025664

Project terminated on 29 June 2023

EC signature date 9 March 2021

Start date 12 July 2021

End date 11 July 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 172 932,48

EU contribution

€ 172 932,48

Coordinated by

UNIVERSIDAD DEL PAIS VASCO/ EUSKAL HERRIKO UNIBERTSITATEA
Spain

Periodic Reporting for period 1 - QESPEM (Light-controlled bright and stable plexcitonic quantum emitters operating in both single-photon and entangled-photon-pair emission modes)

Reporting period: 2021-07-12 to 2023-07-11

Summary of the context and overall objectives of the project

The field of quantum technology has been rapidly expanding in the past decades, yielding numerous applications such as quantum information, quantum communication, and quantum cybersecurity. The central building block for these applications is a quantum emitter, a controllable source of single photons or photon pairs. Semiconductor quantum emitters such as perovskite quantum dots and semiconductor quantum dots have been demonstrated to be promising materials for pure single-photon emission. However, there are still serious challenges that should be addressed to develop ultrabright and stable single-photon sources based on these types of quantum emitters. The most effective way to do this is the fabrication of light–matter coupled hybrid materials using plasmonic nanocavities. Perovskite and semiconductor quantum dots also may serve as sources of photon pairs emitted in one cascade recombination process which allows them to be quantum entangled. However, the low emission efficiency of the cascade recombination strongly limits their use as the source of entangled photon pairs. The light-matter coupling of semiconductor quantum emitters with plasmonic nanocavities can help to increase the efficiency of this process and make stable and bright sources of photon pairs. The main goal of the QESPEM project was to design highly efficient nanoscale plasmon-coupled semiconductor quantum emitters operating as on-demand sources of single photons and pairs of photons.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

One of the first goals of the project was the synthesis of bright semiconductor QEs. A series of bright and stable perovskite nanocrystals and semiconductor quantum dots were synthesized and their arrays were fabricated. To establish the plasmon-exciton interaction with synthesized quantum emitters, several types of silver and gold plasmonic nanoparticles were synthesized. A numerical model was developed and further optimized for the plasmon nanoparticle-based metasurfaces. The optical properties obtained by numerical simulation were in good agreement with the experimental ones and then used for the numerical estimations. According to the results of the numerical simulations, several compositions of plasmonic metasurface and semiconductor quantum emitters types were chosen to ensure different light-matter coupling strengths. For the fabrication of the plasmon-exciton hybrid systems, a novel experimental technique was developed. An array of plasmonic nanoparticles was deposited on a curved glass substrate thus forming a plasmonic metasurface. Then, the metasurface was used to change the properties of fixed quantum emitters during the measurement of the optical properties. The interaction of quantum emitters with the metasurface allowed to significantly increase their emission rate. Depending on the type of the light-matter coupling either the pure single-photon emission was achieved or the photon-pair emission mode. It is also important to note that after the removal of the metasurface, bright quantum emitters returned to the initial state. An irreversible increase in the emission was also found for initially weakly emissive quantum emitters interacting with the metasurface. To measure the properties of the quantum entanglement of the emitted photon pairs, an experimental setup was constructed that allows one to carry out quantum tomographic measurements. Using this setup, all experimental samples created during the project were tested.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

As a result of the project the new direction related to the synthesis of high-quality semiconductor nanocrystals and fabrication of plasmon-exciton quantum emitters was established in the host institution (Centro de Fisica de Materiales, Donostia – San Sebastian, Spain) for the first time. During the project, new insights about the preservation of the single-photon nature of the quantum emitter emission and the significant acceleration of their radiative recombination were found. Beyond the state of the art, the technique of the on-demand reversible switching of the emission mode of individual semiconductor quantum emitters using plasmonic metasurfaces was developed. This result is very important for the development of (quantum emitter)-based devices. This technique is more versatile for future applications than commonly used methods because the plasmonic metasurface is coupled to an array of quantum emitters, impacting all of them collectively. Moreover, the technique can be applied to a wide range of materials with quantum-emitting properties, making it of great interest to scientists working in diverse photonic areas. The novel technique of the plasmon-induced recovery of the arrays of semiconductor quantum emitters was also developed. This result could be applied to the fabrication of any thin-film (quantum dot)-based coverage by increasing their brightness and overall emission efficiency, which is important not only for quantum technology but also for the QLED fabrication industry.
The results of the study were published in 4 peer-reviewed scientific articles, and 2 conference proceedings, and also one review paper and one research paper are in the process of preparation for submission to peer-reviewed scientific journals. The results were reported on 6 international scientific conferences (including one invited presentation), were used for two invited lectures on academic seminars, and were used in the organization of the scientific workshops (science week workshop Zientzia Astea 2021 and 2022 in Donostia – San Sebastian, and Zientzia Azoka 2022 in Bilbao), and also for other outreach activities including Women in Science Day and school students visits. Using the results the training of the researchers of the host group was performed related to the new synthesis methods as well to the operation of the designed quantum tomography setup. No website has been developed for the project.

Plasmon-induced reversible switching of the emission mode of individual semiconductor QEs