We developed a method to use any GFP-tagged construct in single-molecule super-resolution microscopy. By targeting GFP with small, high-affinity antibodies coupled to organic dyes, we achieved nanometer spatial resolution and minimal linkage error when analyzing microtubules, living neurons and yeast cells. We show that in combination with libraries encoding GFP-tagged proteins, virtually any known protein can immediately be used in super-resolution microscopy and that simplified labeling schemes allow high-throughput super-resolution imaging.

nanotechnology, with its broad impact on societally relevant applications, relies heavily on the availability of accessible nanofabrication methods. Even though a host of such techniques exists, the flexible, inexpensive, on-demand and scalable fabrication of functional nanostructures remains largely elusive. Here we present a method involving nanoscale electrohydrodynamic ink-jet printing that may significantly contribute in this direction. A combination of nanoscopic placement precision, soft-landing fluid dynamics, rapid solvent vapourization, and subsequent self-assembly of the ink colloidal content leads to the formation of scaffolds with base diameters equal to that of a single ejected nanodroplet. The virtually material-independent growth of nanostructures into the third dimension is then governed by an autofocussing phenomenon caused by local electrostatic field enhancement, resulting in large aspect ratio. We demonstrate the capabilities of our electrohydrodynamic printing technique with several examples, including the fabrication of plasmonic nanoantennas with features sizes down to 50 nm.

Single emitters have been considered as sources of single photons in various contexts such as cryptography, quantum computation, spectroscopy, and metrology 1,2,3 . The success of these applications will crucially rely on the efficient directional emission of photons into well-defined modes. To accomplish a high efficiency, researchers have investigated microcavities at cryogenic temperatures 4 , photonic nanowires 5, and near-field coupling to metallic nano-antennas 6 . However, despite an impressive progress, the existing realizations substantially fall short of unity collection efficiency. Here we report on a theoretical and experimental study of a dielectric planar antenna, which uses a layered structure for tailoring the angular emission of a single oriented molecule. We demonstrate a collection efficiency of 96% using a microscope objective at room temperature and obtain record detection rates of about 50 MHz. Our scheme is wavelength-insensitive and can be readily extended to other solid-state emitters such as color centers 7 and semiconductor quantum dots 8 .One of the most powerful and versatile approaches to the generation of single photons exploits the property that a single quantum mechanical two-level system cannot emit two photons simultaneously since each excitation and emission cycle requires a finite time. Unfortunately, such single-photon sources (SPS) are intrinsically inefficient because their radiation spreads over a 4π solid angle and cannot be fully captured by conventional optics. Several years ago, a simple avenue for efficient photon collection was proposed by Koyama et al. in the context of fluorescence microscopy 9 , where emitters were placed at the interface between two media with large refractive index contrast 9,10 . Such a structure can be viewed as a dielectric antenna 11 in which the dipolar radiation of the emitter is funneled into the high-index substrate. The black trace in Fig. 1a shows the angular emission of a dipole sitting close to an interface and oriented perpendicular to it. Despite the strongly modified radiation pattern, one finds that 14% of the light is still lost to the upper half-space, and more importantly, a considerable amount of light is directed to very large angles in the lower substrate, which are not accessible by the collection optics. In this Letter, we remedy these issues by embedding the emitter in a dielectric layer that we engineer on top of the highindex substrate and obtain unprecedented photon collection efficiencies, directionality, and count rates.To provide an intuitive explanation of our antenna design, let us decompose the radiation of a dipolar emitter into plane waves and consider the propagation of each component 12. This

of ultrathin, artificial surfaces, so-called metasurfaces, for manipulating the propagation of light at will. [1,2] Metasurfaces control the propagation of light by abruptly changing its phase, amplitude, polarization, or spectrum at a surface and within a thin (quasi-2D) layer using large arrays of optical scatterers with subwavelength separation. Ideally, each scatterer can be independently engineered in order to locally influence the wavelets of the impinging light, and therefore, arbitrarily reform the wavefront. This concept has been exploited to create a variety of flat optical elements such as beam deflectors, [3][4][5] lenses, [6][7][8] and holograms. [9,10] As compared to bulky refraction-based optical elements, these surfaces are of subwavelength or wavelength-scale thickness, which enables their integration into compact devices. A main feature of the majority of such flat optical elements is that they are passive, and once fabricated, their optical functionalities are invariable. A beam deflector of this kind will direct light of a certain wavelength and direction always into the same direction, or a lens will focus light always to the same focal point. A broad range of new applications could be enabled if it were possible to actively and reversibly change the functionality of metasurfaces after their fabrication. With such "adaptive" metasurfaces beam deflectors with adjustable angle of deflection, metalenses with variable focal length or dynamic holograms may be realized. Advances toward such active devices are highly relevant for applications such as light detection and ranging [11] (LIDAR) sensing for driverless cars, dynamic zoom lenses for miniaturized camera systems [12] (e.g., in smartphones), or holographic displays for augmented reality devices. [13] An adaptive metasurface allows for the dynamic adjustment of an optical functionality of the surface. As shown in Figure 1, for the specific case of a metalens, these surfaces can be categorized based on their degree of dynamic adaptivity. While a passive surface has a fixed functionality, a switchable metasurface allows for switching back and forth between two (or more) predefined states (e.g., switching between different focal lengths, deflection angles, or hologram images). A continuously tunable metasurface enables continuous adjustment of a property within a range (e.g., tunable focal length or deflection angle). Finally, a freely tunable metasurface allows for continuous, arbitrary adjustment of a property, for example, 3D adjustment of the focal point of the metalens shown in Figure 1. Adaptive functionalities can be added to metasurfaces with different methods, for example, by mechanically rearranging the scatterers on the surface with respect to each other, or modifying

Single emitters have been considered as sources of single photons in various contexts such as cryptography, quantum computation, spectroscopy, and metrology 1,2,3 . The success of these applications will crucially rely on the efficient directional emission of photons into well-defined modes. To accomplish a high efficiency, researchers have investigated microcavities at cryogenic temperatures 4 , photonic nanowires 5, and near-field coupling to metallic nano-antennas 6 . However, despite an impressive progress, the existing realizations substantially fall short of unity collection efficiency. Here we report on a theoretical and experimental study of a dielectric planar antenna, which uses a layered structure for tailoring the angular emission of a single oriented molecule. We demonstrate a collection efficiency of 96% using a microscope objective at room temperature and obtain record detection rates of about 50 MHz. Our scheme is wavelength-insensitive and can be readily extended to other solid-state emitters such as color centers 7 and semiconductor quantum dots 8 .One of the most powerful and versatile approaches to the generation of single photons exploits the property that a single quantum mechanical two-level system cannot emit two photons simultaneously since each excitation and emission cycle requires a finite time. Unfortunately, such single-photon sources (SPS) are intrinsically inefficient because their radiation spreads over a 4π solid angle and cannot be fully captured by conventional optics. Several years ago, a simple avenue for efficient photon collection was proposed by Koyama et al. in the context of fluorescence microscopy 9 , where emitters were placed at the interface between two media with large refractive index contrast 9,10 . Such a structure can be viewed as a dielectric antenna 11 in which the dipolar radiation of the emitter is funneled into the high-index substrate. The black trace in Fig. 1a shows the angular emission of a dipole sitting close to an interface and oriented perpendicular to it. Despite the strongly modified radiation pattern, one finds that 14% of the light is still lost to the upper half-space, and more importantly, a considerable amount of light is directed to very large angles in the lower substrate, which are not accessible by the collection optics. In this Letter, we remedy these issues by embedding the emitter in a dielectric layer that we engineer on top of the highindex substrate and obtain unprecedented photon collection efficiencies, directionality, and count rates.To provide an intuitive explanation of our antenna design, let us decompose the radiation of a dipolar emitter into plane waves and consider the propagation of each component 12. This