Unidirectional Meta-Emitters Based on the Kerker Condition Assembled by DNA Origami.

Optical quantum emitters near nanostructures have access to additional relaxation channels and thus exhibit structure-dependent emission properties, including quantum yield and emission directionality. A well-engineered quantum emitter-plasmonic nanostructure hybrid can be considered as an optical meta-emitter consisting of a transmitting nanoantenna driven by an optical-frequency generator. In this work, the DNA origami fabrication method is used to construct ultracompact unidirectional meta-emitters composed of a plasmonic trimer nanoantenna driven by a single dye molecule.

DNA Origami Assembled Nanoantennas for Manipulating Single-Molecule Spectral Emission.

The emission spectrum of a dye is given by the energy of all of the possible radiative transitions weighted by their probability. This spectrum can be altered with optical nanoantennas that are able to manipulate the decay rate of nearby emitters by modifying the local density of photonic states. Here, we make use of DNA origami to precisely place an individual dye at different positions around a gold nanorod and show how this affects the emission spectrum of the dye.

Broadband Plasmonic Nanoantennas for Multi-Color Nanoscale Dynamics in Living Cells.

Recently, the implementation of plasmonic nanoantennas has opened new possibilities to investigate the nanoscale dynamics of individual biomolecules in living cells. However, studies so far have been restricted to single molecular species as the narrow wavelength resonance of gold-based nanostructures precludes the simultaneous interrogation of different fluorescently labeled molecules. Here, broadband aluminum-based nanoantennas carved at the apex of near-field probes are exploited to resolve nanoscale-dynamic molecular interactions on living cell membranes.

Optical Ultracompact Directional Antennas Based on a Dimer Nanorod Structure.

Controlling directionality of optical emitters is of utmost importance for their application in communication and biosensing devices. Metallic nanoantennas have been proven to affect both excitation and emission properties of nearby emitters, including the directionality of their emission. In this regard, optical directional nanoantennas based on a Yagi-Uda design have been demonstrated in the visible range.

DNA-Templated Ultracompact Optical Antennas for Unidirectional Single-Molecule Emission.

Optical antennas are nanostructures designed to manipulate light-matter interactions by interfacing propagating light with localized optical fields. In recent years, numerous devices have been realized to efficiently tailor the absorption and/or emission rates of fluorophores. By contrast, modifying the spatial characteristics of their radiation fields remains challenging.

Frequency-Encoded Multicolor Fluorescence Imaging with Single-Photon-Counting Color-Blind Detection.

Standard fluorescence microscopy relies on filter-based detection of emitted photons after fluorophore excitation at the appropriate wavelength. Although of enormous utility to the biological community, the implementation of approaches for simultaneous multicolor fluorescence imaging is commonly challenged by the large spectral overlap between different fluorophores. Here, we describe an alternative multicolor fluorescence imaging methodology that exclusively relies on the absorption spectra of the fluorophores instead of their fluorescence emissions.

Enhancing Magnetic Light Emission with All-Dielectric Optical Nanoantennas.

Electric and magnetic optical fields carry the same amount of energy. Nevertheless, the efficiency with which matter interacts with electric optical fields is commonly accepted to be at least 4 orders of magnitude higher than with magnetic optical fields. Here, we experimentally demonstrate that properly designed photonic nanoantennas can selectively manipulate the magnetic versus electric emission of luminescent nanocrystals.

Broadband Fluorescence Enhancement with Self-Assembled Silver Nanoparticle Optical Antennas.

Plasmonic structures are known to affect the fluorescence properties of dyes placed in close proximity. This effect has been exploited in combination with single-molecule techniques for several applications in the field of biosensing. Among these plasmonic structures, top-down zero-mode waveguides stand out due to their broadband capabilities.

DNA Origami Nanoantennas with over 5000-fold Fluorescence Enhancement and Single-Molecule Detection at 25 μM.

Optical nanoantennas are known to focus freely propagating light and reversely to mediate the emission of a light source located at the nanoantenna hotspot. These effects were previously exploited for fluorescence enhancement and single-molecule detection at elevated concentrations. We present a new generation of self-assembled DNA origami based optical nanoantennas with improved robustness, reduced interparticle distance, and optimized quantum-yield improvement to achieve more than 5000-fold fluorescence enhancement and single-molecule detection at 25 μM background fluorophore concentration.