Supplementary document for Manipulating Random Lasing Correlations in Doped Liquid Crystals - 6873400.pdf

Supplementary Information

Soft Periodic Microstructures Containing Liquid Crystals

An empty polymeric structure has been realized by combining a high precision level optical holographic setup and a selective microfluidic etching process. The distinctive features of the realized periodic microstructure enabled aligning several kinds of liquid crystal (LC) compounds, without the need of any kind of surface chemistry or functionalization. In particular, it has been possible to exploit light sensitive LCs for the fabrication of all-optical devices, cholesteric and ferroelectric LCs for ultrafast electro-optical switches, and a common LC for a two-dimensional periodic structure with high anisotropy. All-optical and electro-optical experiments, performed for investigating the samples in terms of switching voltages and response times, confirm good performances of the realized devices

Directed Organization of DNA Filaments in a Soft Matter Template

We have developed a noninvasive, all-optical, holographic technique for permanently aligning liquid crystalline DNA filaments in a microperiodic template realized in soft-composite (polymeric) materials. By combining optical intensity holography with a selective microfluidic etching process, a channelled microstructure has been realized which enables self-assembly of DNA. The striking chemicophysical properties of the structure immobilize the DNA filaments within the microchannels without the need of any kind of surface chemistry or functionalization. Polarized optical, confocal, and electronic microscopies have been used for characterizing the DNA geometry inside the microchannels in terms of birefringence, fluorescence, and nanoscale organization properties. In particular, observation of a far-field diffraction pattern confirms a periodic organization of the DNA filaments inside the polymeric template

Loss-Mitigated Collective Resonances in Gain-Assisted Plasmonic Mesocapsules

Inherent optical losses of plasmonic materials represent a crucial issue for optoplasmonics, whereas the realization of hierarchical plasmonic nanostructures implemented with gain functionalities is a promising and valuable solution to the problem. Here we demonstrate that porous silica capsules embedding gold nanoparticles (Au NPs) and fabricated at a scale intermediate between the single plasmonic nanostructure and bulk materials show remarkable form–function relations. At this scale, in fact, the plasmon–gain interplay is dominated by the location of the gain medium with respect to the spatial distribution of the local field. In particular, the hollow spherical cavities of these structures allow regions of uniform plasmonic field where the energy transfer occurring between chromophoric donors and the surrounding plasmonic acceptors gives rise to a broadband attenuation of losses

Interface of Physics and Biology: Engineering Virus-Based Nanoparticles for Biophotonics

Virus-based nanoparticles (VNPs) have been used for a wide range of applications, spanning basic materials science and translational medicine. Their propensity to self-assemble into precise structures that offer a three-dimensional scaffold for functionalization has led to their use as optical contrast agents and related biophotonics applications. A number of fluorescently labeled platforms have been developed and their utility in optical imaging demonstrated, yet their optical properties have not been investigated in detail. In this study, two VNPs of varying architectures were compared side-by-side to determine the impact of dye density, dye localization, conjugation chemistry, and microenvironment on the optical properties of the probes. Dyes were attached to icosahedral cowpea mosaic virus (CPMV) and rod-shaped tobacco mosaic virus (TMV) through a range of chemistries to target particular side chains displayed at specific locations around the virus. The fluorescence intensity and lifetime of the particles were determined, first using photochemical experiments on the benchtop, and second in imaging experiments using tissue culture experiments. The virus-based optical probes were found to be extraordinarily robust under ultrashort, pulsed laser light conditions with a significant amount of excitation energy, maintaining structural and chemical stability. The most effective fluorescence output was achieved through dye placement at optimized densities coupled to the exterior surface avoiding conjugated ring systems. Lifetime measurements indicate that fluorescence output depends not only on spacing the fluorophores, but also on dimer stacking and configurational changes leading to radiationless relaxationand these processes are related to the conjugation chemistry and nanoparticle shape. For biological applications, the particles were also examined in tissue culture, from which it was found that the optical properties differed from those found on the benchtop due to effects from cellular processes and uptake kinetics. Data indicate that fluorescent cargos are released in the endolysosomal compartment of the cell targeted by the virus-based optical probes. These studies provide insight into the optical properties and fates of fluorescent proteinaceous imaging probes. The cellular release of cargo has implications not only for virus-based optical probes, but also for drug delivery and release systems