5 research outputs found
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 relaxationand
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