ICN2 Nanoseminar in Physics

ONLINE EVENT -  Register HERE to attend 

Speaker: Dr Constanza Toninelli,  CNR-INO and LENS, Sesto Fiorentino, Florence, Italy

Abstract: The successful development of future photonic quantum technologies will much depend on the possibility of realizing robust and scalable nanophotonic devices. These should include quantum emitters like on-demand single-photon sources and non-linear elements, provided their transition linewidth is broadened only by spontaneous emission. However, conventional strategies to on-chip integration, based on lithographic processes in semiconductors, are typically detrimental for the coherence properties of the emitter. Moreover, such approaches are difficult to scale and bear limitations in terms of geometries. In the present contribution, we discuss an alternative platform, based on molecules that preserve near-Fourier-limited fluorescence even when embedded in polymeric photonic structures. Anthracene nanocrystals doped with dibenzoterrylene (DBT:Ac NCX) fluorescent molecules show excellent performances of single-photon emission and are naturally suitable both to deterministic positioning and to the integration in hybrid devices [1]. Threedimensional patterns are achieved by Direct Laser Writing (DLW) of commercial photoresists around self-assembled organic nanocrystals containing fluorescent molecules [2,3]. This method enables fast, inexpensive and scalable fabrication process, while offering unique advantages in terms of versatility and sub-micron resolution. We also show optical tuning of many molecules on chip [4], unlocking twophoton interference from distinct emitters on chip [5,6]. The proposed technology will allow for competitive organic quantum devices, including integrated multi-photon interferometers, arrays of indistinguishable single-photon sources and hybrid electrooptical nanophotonic chips.

References

[1] S. Pazzagli, et al., “Photostable single-photon emission from self-assembled nanocrystals of polycyclic aromatic hydrocarbons”, ACS Nano 12, 4295−4303 (2018)

[2] M. Colautti, et al., “Quantum optics with single molecules in a threedimensional polymeric platform”, Advanced Quantum technologies 3, 7 cover (2020)

[3] C. Ciancico, et al., “Narrow Line Width Quantum Emitters in an ElectronBeam-Shaped Polymer”, ACS Photonics 6, 12, 3120–3125 (2019)

[4] M. Colautti, et al., “Laser-Induced Frequency Tuning of Fourier-Limited Single-Molecule Emitters”, ACS Nano (2020) 10.1021/acsnano.0c05620

[5] P.Lombardi et al., ”Triggered emission of indistinguishable photons from an organic dye molecule ”, Appl. Phys. Lett. 118, 204002 (2021)

[6] R. Duquennoy et al., arXiv:2201.07140v1

Introductory talk: "Dielectric substrate characterization using plasmonic nanoantennas " by Dr Martin Poblet. Senior Postdoctoral Researcher at Phononic and Photonic Nanostructures Group at ICN2

Introductory Talk Abstract: After excitation of a plasmonic nanoantenna with pulsed light at the appropriate wavelength, an excited electron population is generated in the metal followed by thermalization and heating of the lattice. This cascade of energy transfer leads to coherent excitation of normal modes of mechanical oscillation known as acoustic coherent phonons, detectable in an experimental pump-probe configuration. This scenario converts nanoantennas into local mechanical nano-resonators with tunable frequencies from a few GHz to THz. Due to the dynamic contact in the regions of attachment, mechanical energy will be transferred to the substrate and will result in the propagation of Surface Acoustic Waves (SAWs) through it. SAWs propagating in materials, and detected in the far filed, are currently a highly accurate electro and optomechanical characterization tool in various fields of applications, such as nanoscale non-destructive fatigue crack detection and measurement of mechanical properties of solid materials in the GHz regime. The SAWs detection in the far-field, due to its small amplitude, requires such a sensitivity that only few systems are able to provide. Plasmonic nanoantennas, tuned to their optical resonance, have demonstrated their effectiveness in detecting this type of perturbations, showing their high sensitivity to mechanical excitations. During this talk I will show how using plasmonic nanoantennas, a substrate can be characterized at the nanoscale in the GHz regime.