_applied sciences_  
_Eiditorial_ Special Issue on Advances in Dielectric Photonic Devices and Systems beyond the Visible_  
**[PERSON] 1,*(r)**, **[PERSON] 1** and [PERSON] 2**  
The impressive advances in dielectric photonics, integrated optics, and optical fiber-based systems are paving the way for increasingly challenging applications in wide research areas. Disruptive results in biomedicine, medical diagnostics, and therapy have been obtained via bio-photonics, e.g., by exploiting antibacterial agents in photodynamic therapy, bio-glasses synthesis, and the interaction of light with biological tissues. Microstructures and nanoparticles included in glass are exploited by optical fibers and planar optics devices, in addition to photonic crystals and gratings, to obtain high-performance sensing. The improvement of sensor performances can be obtained by constructing periodic pillar arrays by covering the dielectric structure with thin metal layers and exploiting plasmon propagation or resonances. Novel materials, such as graphene, promise high-impact applications in microwaves, for the construction of phase shifters to optics, e.g., for obtaining absorbers. As a direct consequence of the abovementioned advances in photonics, optical amplification and optical communication are important to obtain efficient optical signal transport and to fully exploit the information of all optical systems. This Special Issue collects seven original contributions and one review paper on the abovementioned topics, including optical devices and systems beyond the visible, which cover a wide area of interest ranging from sensing and biomedicine to telecommunication. Concerning bio-photonics, in [1], new derivatives of zirconium (IV) phthalocyanine (ZrPc) complexes linked to graphite oxide flakes have been considered. The optical properties, i.e., absorption and photoluminescence spectra, of ZrPcs and the composites are examined. Broadband red-near-infrared lamp is exploited to activate ZrPcs and the composites. Modified activity levels toward different bacterial strains are discussed, showing the potential of merging optic technology and medical expertise. Optical biosensing and time-dependent monitoring of nanoparticle-biofluid interactions via Modulated 3D Cross-Correlation Dynamic Light Scattering have been described in [2]. In particular, paper [2] reviews dynamic light scattering (DLS) of gold nanoparticle-protein interactions for the model protein bovine serum albumin (BSA), as well as in complex biofluids. The paper illustrates that it is possible to differentiate rotational and translational motion, as well as agglomerate formation. Moreover, time-dependent monitoring of protein-nanorod interactions and monitoring of serum, with the use of nanoparticles, permits the detection of either the change of hydrodynamic radii of the components of the particles or of monitoring nanoparticle motion in the presence of serum. In general, high-performance sensing is strongly required in robotics, aerospace, automotive, and industrial material processing. In [3], two-dimensional (2D) arrays of polymethyl-methacrylate (PMMA) nano-pillars deposited on Metallo-Dielectric Films are proposed by the authors to fabricate the periodic array enabling the phase-matching of the incident plane wave, thus exciting suitable optical resonances. These mechanically stable nano-pillars promise to be fully exploited for the fabrication of novel Metallo-Dielectric core/shell structures for sensing, surface-enhanced Raman spectroscopy, and light-matter interactions. Similar periodic structures can be constructed on graphene layers, obtaining a different behavior. In [4], two-dimensional dielectric gratings were proposed to achieve high absorption in monolayer graphene at visible and near-infrared frequencies. The dielectric gratings are employed to couple light with the graphene layer.