Quantum emission (QE) is a process where a photon is emitted one at the time and has large technological relevance in quantum communications protocols (such as cryptography and quantum key distributions). The QE in solid state N-based materials (hBN, AlN, GaN, and SiN) is appealing owing to their room temperature
operations, high brightness, strong polarization, and wavelength tunability. These emitters originate from localized defects with well-defined electronic states that upon excitation (thermal/electromagnetic) emit singular photons. However, despite their potential, the microscopic mechanism leading to QE in solid state
materials is still unknown. Recently, I showed [Pelliciari et al. Nat. Mat. 23, 1230 (2024)] using Resonant Inelastic X-Ray Scattering (RIXS) and photoluminescence (PL) that QE in hBN stems from a defect resembling the N2 molecule whose vibrations and harmonics, extending from the mid-IR up to the UV, seed a donor acceptor pair process generating QE over a large energy window. This discovery shifts our perspective on QE in hBN by revealing a regular energy scale attributed to N2-like vibrations giving predictability and enabling the resonant stimulation of these modes with light pulses and their coupling to photonics cavity modes allowing the control of their functionalities. In this project, I want to uncover the response of hBN emitters upon pumping the vibrations of the N2-like defects with light pulses and investigate the effect of resonantly coupling cavity modes to these vibrations. Finally, I will explore whether the QE based on molecular-defect is a prerogative of hBN or takes places in N-based materials such as AlN, GaN, and SiN.
To achieve this, I will use RIXS, PL, and pump-probe schemes to uncover the electronic transitions of molecular defects in N-based materials, their energy/time response to resonant light and cavity fields, and their microscopic (orbital) nature. Ultimately, this project will prove and generalize molecular-like defects as the origin of QE in N-based systems and unveil their response to light stimuli and confinement in photonic cavities, paving the way for device fabrication and opening an unprecedented research line in an emerging field at the interconnection between condensed matter physics, photonics, and quantum information science.