Coherent Networks of Si Nanocrystals: Tunable Collective Resonances with Narrow Spectral Widths. Issue 4 (22nd February 2021)

• Record Type: Journal Article
• Authors: Sadeghi, Seyed M.; Gutha, Rithvik R.
• Is Part Of: Advanced photonics research. Volume 2:Issue 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-22
• Subjects: coherent networks -- collectives -- lattices -- resonances -- silicon nanocrystals; Photonics -- Periodicals; 621.36505
• DOI: 10.1002/adpr.202000129
• Languages: English
• ISSNs: 2699-9293

Abstract

Abstract : The ultralong coherent networks of Si nanocrystals (NCs) via lattice‐enhanced dipole–dipole coupling and the formation of disordered arrays of phase‐correlated field hotspots are studied. Such arrays occur in structures consisting of Si NCs randomly positioned inside long strips that are periodically repeated. The theoretical results predict the formation of all‐dielectric coherent networks of Si NCs, formed via in‐phase coupling of the resonances generated by diffraction of light. Such networks are extended along the lengths of the strips while supporting high field enhancement associated with the phase‐correlated chains of field hotspots between the nanocrystals. It is shown that these phenomena occur at the wavelengths where the Rayleigh anomaly condition is satisfied. Under this condition the electric field is squeezed between two field‐impenetrable regions, causing efficient concentration of electromagnetic energy along the disordered arrays of Si NCs in each strip. The results show that these arrays act as coherently assembled units that are efficiently coupled with the lattice modes, forming highly tunable collective resonances with spectral widths less than 5 nm. These results pave the way for all‐dielectric‐tunable optical filters with very small losses and near‐perfect reflectivity and laser systems based on Si NCs. Abstract : Long coherent networks of Si nanocrystals (NCs) are generated when Si NCs are randomly positioned inside long trips that are periodically repeated. The key mechanisms are lattice‐enhanced dipole–dipole coupling and the formation of disordered arrays of phase‐correlated field hotspots inside each strip. Tunable all‐dielectric narrow‐linewidth optical filters with small losses are predicted.