Biocompatible silk random lasing is obtained by nanostructuring silk proteins into a disordered porous matrix via a self-assembly technique. Lasing action is revealed by spectral narrowing and threshold behavior, and it is sensitive to pH variations in the aqueous environment. Silk random lasing provides a versatile biocompatible system, opening up opportunities for biophotonic applications and biosensing
Conventional nanophotonic schemes minimise multiple scattering to realise a miniaturised version of beam-splitters, interferometers and optical cavities for light propagation and lasing. Here instead, we introduce a nanophotonic network built from multiple paths and interference, to control and enhance light-matter interaction via light localisation. The network is built from a mesh of subwavelength waveguides, and can sustain localised modes and mirror-less light trapping stemming from interference over hundreds of nodes. With optical gain, these modes can easily lase, reaching ~100 pm linewidths. We introduce a graph solution to the Maxwell’s equation which describes light on the network, and predicts lasing action. In this framework, the network optical modes can be designed via the network connectivity and topology, and lasing can be tailored and enhanced by the network shape. Nanophotonic networks pave the way for new laser device architectures, which can be used for sensitive biosensing and on-chip optical information processing.
Nanoscale generation of individual photons in confined geometries is an exciting research field aiming at exploiting localized electromagnetic fields for light manipulation. One of the outstanding challenges of photonic systems combining emitters with nanostructured media is the selective channelling of photons emitted by embedded sources into specific optical modes and their transport at distant locations in integrated systems. Here, we show that soft-matter nanofibers, electrospun with embedded emitters, combine subwavelength field localization and large broadband near-field coupling with low propagation losses. By momentum spectroscopy, we quantify the modal coupling efficiency identifying the regime of single-mode coupling. These nanofibers do not rely on resonant interactions, making them ideal for room-temperature operation, and offer a scalable platform for future quantum information technology.
Quantum emitters radiate light omni-directionally, making it hard to collect and use the generated photons. Here, we propose a three-dimensional metal-dielectric parabolic antenna surrounding an individual quantum dot as a source of collimated single photons, which can then be easily extracted and manipulated. Our fabrication method relies on a single optically induced polymerization step once the selected emitter has been localized by confocal microscopy. Compared to conventional nanoantennas, our geometry does not require near-field coupling, and it is, therefore, very robust against misalignment issues and minimally affected by absorption in the metal. The parabolic antenna provides one of the largest reported experimental directivities ( D = 106) and the lowest beam divergences (Θ = 13.5°) and a broadband operation over all of the visible and near-infrared range together with extraction efficiency of more than 96%, offering a practical advantage for quantum technological applications.
Hyperuniform geometries feature correlated disordered topologies which follow from a tailored k-space design. Here we study gold plasmonic hyperuniform metasurfaces and we report evidence of the effectiveness of k-space engineering on both light scattering and light emission experiments. The metasurfaces possess interesting directional emission properties which are revealed by momentum spectroscopy as diffraction and fluorescence emission rings at size-specific k-vectors. The opening of these rotational-symmetric patterns scales with the hyperuniform correlation length parameter as predicted via the spectral function method.Coherent control of optical waves by scattering from 2D nanostructured surfaces is revolutionising the way we shape the wavefront of an incoming light beam, opening new avenues for miniaturised optical components for integrated optical circuits [1], flat display technology [2], and energy harvesting [3,4]. Metallic surfaces are in particular attractive due to the strong light-matter interaction associated with surface plasmons, enabling diffraction control through plasmonic crystals [5, 6] and metal nano-particle arrays [7,8], broadband operation and increase of the plasmon mode density [9], enhanced omnidirectional light extraction and coupling [10], broadband absorption [11], fluorescence enhancement [12] and lasing [13,14], and more recently the realisation of ultra thin lenses [15] and metasurface holograms [16].Whereas periodic geometries suffer from limited rotational symmetries, aperiodic and disordered topologies, with their richer symmetries and patterns, can lead to superior optical functionalities [8], as in omnidirectional absorption for solar applications [17,18], scattering-induced light localisation [19] and light extraction from LED/OLED [20]. Moreover, disordered metasurfaces are expected to be more resilient against fabrication imperfection and therefore more apt for technological implementation. Given the vast possible designs of non-periodic topologies, ranging from random to correlated-disordered, their full potential is still to be fully explored.There exists a general class of disordered systems, called hyperuniform disordered (HuD) photonic structures, which are of particular interest because they exhibit wide and isotropic photonic band gaps [21], rotational symmetry and broadband k-space control, and can be systematically generated through a specific design rule via universal tessellation protocol [22,23]. Pioneering experiments on photonic HuD systems have explored IR light diffraction in 3D dielectric structures [24], microwave band-gaps formation [25], polarization filtering [26] and random quantum cascade lasers [27]. Theoretical proposals have been put forward for surface enhanced Raman scattering [28], transparency design [29], high-Q optical cavities and low-loss waveguides [30-32], and microwave photonic circuits [25]. HuD structures fabrication is improving quickly, reaching already the IR range [24] but not yet the visible.Here, we report visible light scatt...
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