Executive Summary : | Formation and control of the structured light exploiting the unique symmetry property of the material like chirality is an exciting field in advanced photonics [1]. Chirality and its optical manifestation are well explored in plasmonic nanostructures [2]. The proposal constitutes a bridge between Nonlinear Optics and Nanophotonics, aiming at the development of a novel platform for manipulating the polarization and the spatial pattern of structured light. This research vision is reinforced by the exploitation of nonlinear (NL) waves and the Orbital Angular Momentum (OAM) of twisted photons manipulated by modern nanophotonic materials enabling nanoscale operation, as in particular metamaterials [3]. The proposal aims at generating and controlling the vortex structure of twisted photons in random Twisted metamaterials (TMMs) embedding active media with the ultimate goal of developing a new generation of random lasers [4] producing optical vortices (OVs) with tunable OAM, which can open new groundbreaking applications in spectroscopy, sensing, and vortex-enhanced optical communication systems [1]. Indeed, such disorder-based OV sources would operate without a photonic cavity and are promising for cost-effective implementation of the applications outlined above. This endeavour will be approached through the theoretical investigation of novel light-matter interaction regimes in active TMMs to generate OVs with tuneable OAM. The full set of state-of-the-art know-how in Nanophotonics and Nonlinear Optics will be exploited to investigate dissipative nonlinear dynamics of OVs in chiral random lasers (CRLs) composed of TMMs embedding externally pumped active molecules to accomplish the following scientific objectives: I. Engineering TMM nonlinearity to achieve spatial self-organization of stable vortex dissipative solitons (VDSs), enabling single-mode operation in seeded RLs with high-quality output beams; II. Spatio-temporal tailoring of stable VDSs to attain mode-locked pulsed operation, producing bullets with tunable pulse duration and OAM. References: [1] H. Rubinsztein et.al. , "Roadmap on structured light, ,J. Opt. 19, 013001 (2017); [2] M. Hentschel et.al. "Chiral plasmonics", Science Advances 3, e1602735 (2017); [3] A. M. Urbas et. al., "Roadmap on optical metamaterials", J. Opt. 18, 093005 (2016); [4] D. S. Wiersma, "The physics and applications of random lasers", Nature Physics 4, 359 - 367(2008). |