We have developed a generic approach to engineer tubular micro‐/nanostructures out of many different materials (see figure) with tunable diameters and lengths by precisely releasing and rolling up functional nanomembranes on polymers. The technology spans across different scientific fields ranging from photonics to biophysics and we demonstrate optical ring resonators, magneto‐fluidic sensors, remotely controlled microjets and 2D confined channels for cell growth guiding.

Strain-engineered microtubes with an inner catalytic surface serve as self-propelled microjet engines with speeds of up to approximately 2 mm s(-1) (approximately 50 body lengths per second). The motion of the microjets is caused by gas bubbles ejecting from one opening of the tube, and the velocity can be well approximated by the product of the bubble radius and the bubble ejection frequency. Trajectories of various different geometries are well visualized by long microbubble tails. If a magnetic layer is integrated into the wall of the microjet engine, we can control and localize the trajectories by applying external rotating magnetic fields. Fluid (i.e., fuel) pumping through the microtubes is revealed and directly clarifies the working principle of the catalytic microjet engines.

The temperature distribution throughout arrays of illuminated metal nanoparticles is investigated numerically and experimentally. The two cases of continuous and femtosecond-pulsed illumination are addressed. In the case of continuous illumination, two distinct regimes are evidenced: a temperature confinement regime, where the temperature increase remains confined at the vicinity of each nanosource of heat, and a temperature delocalization regime, where the temperature is uniform throughout the whole nanoparticle assembly despite the heat sources' nanometric size. We show that the occurrence of one regime or another simply depends on the geometry of the nanoparticle distribution. In particular, we derived (i) simple expressions of dimensionless parameters aimed at predicting the degree of temperature confinement and (ii) analytical expressions aimed at estimating the actual temperature increase at the center of an assembly of nanoparticles under illumination, preventing heavy numerical simulations. All these theoretical results are supported by experimental measurements of the temperature distribution on regular arrays of gold nanoparticles under illumination. In the case of femtosecond-pulsed illumination, we explain the two conditions that must be fulfilled to observe a further enhanced temperature spatial confinement.

Efficient light-matter interaction lies at the heart of many emerging technologies that seek on-chip integration of solid-state photonic systems. Plasmonic waveguides, which guide the radiation in the form of strongly confined surface plasmon-polariton modes, represent a promising solution to manipulate single photons in coplanar architectures with unprecedented small footprints. Here we demonstrate coupling of the emission from a single quantum emitter to the channel plasmon polaritons supported by a V-groove plasmonic waveguide. Extensive theoretical simulations enable us to determine the position and orientation of the quantum emitter for optimum coupling. Concomitantly with these predictions, we demonstrate experimentally that 42% of a single nitrogen-vacancy centre emission efficiently couples into the supported modes of the V-groove. This work paves the way towards practical realization of efficient and long distance transfer of energy for integrated solid-state quantum systems.

Superconducting nanowire single-photon detectors ͑SNSPDs͒ have emerged as a highly promising infrared single-photon detector technology. Next-generation devices are being developed with enhanced detection efficiency ͑DE͒ at key technological wavelengths via the use of optical cavities. Furthermore, new materials and substrates are being explored for improved fabrication versatility, higher DE, and lower dark counts. We report on the practical performance of packaged NbTiN SNSPDs fabricated on oxidized silicon substrates in the wavelength range from 830 to 1700 nm. We exploit constructive interference from the SiO 2 / Si interface in order to achieve enhanced front-side fiber-coupled DE of 23.2 % at 1310 nm, at 1 kHz dark count rate, with 60 ps full width half maximum timing jitter. © 2010 American Institute of Physics. ͓doi:10.1063/1.3428960͔Infrared single-photon detectors are a key enabling technology for a host of scientific applications. Advanced photon-counting applications place stringent demands on detector performance, and new detector technologies are rapidly being developed, evaluated, and deployed.1 Superconducting nanowire single-photon detectors ͑SNSPDs͒ ͑Refs. 2-4͒ offer wide spectral range ͑from visible to midinfrared wavelengths͒ with free-running operation, low dark counts, short reset times, and low timing jitter. SNSPDs have begun to have a significant impact on applications, such as quantum key distribution, 5 time-of-flight ranging, 6 high bit-rate ground-to-space communications, 7 and optical quantum information processing.8 Recent work on SNSPDs has concentrated on increasing detection efficiency ͑DE͒ through improved materials, device layout, and optical architecture. 3,4,[9][10][11][12] Optical cavities increase the absorption of photons in the active device layer 9-11 and nanopositioning systems are employed to maximize coupling efficiency to the device area. 12The ϳ1300 nm wavelength range is important for quantum information experiments using telecom-wavelength quantum-dot single-photon sources 13 and medical applications such as singlet oxygen detection at = 1273 nm.14 In this paper we report on enhanced device efficiency in a NbTiN SNSPD ͑Ref. 15͒ with a cavity reflection from the oxidized Si substrate optimized for ϳ1300 nm wavelength. The devices are front-side fiber-coupled in a fixed package without the need for nanopositioners or thinning of the substrate used in backside illumination architectures. 9,10,12 In this paper, we describe device performance as a function of wavelength, with reference to the device architecture. We demonstrate the highest published efficiency in a practically packaged SNSPD at = 1310 nm with frontside fiber illumination, comparable to results achieved with backside illumination.Devices used in this study 15 are based on high quality films of NbTiN deposited by reactive dc magnetron sputtering at room temperature on a Si substrate with a 225 nm SiO 2 layer. 16 Further device fabrication details are given in Ref. 15. The devices studied consist of a 10...

Plasmonic antennas are key elements to control the luminescence of quantum emitters. However, the antenna's influence is often hidden by quenching losses. Here, the luminescence of a quantum dot coupled to a gold dimer antenna is investigated. Detailed analysis of the multiply excited states quantifies the antenna's influence on the excitation intensity and the luminescence quantum yield separately

Next-generation optoelectronic devices and photonic circuitry will have to incorporate on-chip compatible nanolaser sources. Semiconductor nanowire lasers have emerged as strong candidates for integrated systems with applications ranging from ultrasensitive sensing to data communication technologies. Despite significant advances in their fundamental aspects, the integration within scalable photonic circuitry remains challenging. Here we report on the realization of hybrid photonic devices consisting of nanowire lasers integrated with wafer-scale lithographically designed V-groove plasmonic waveguides. We present experimental evidence of the lasing emission and coupling into the propagating modes of the V-grooves, enabling on-chip routing of coherent and subdiffraction confined light with room-temperature operation. Theoretical considerations suggest that the observed lasing is enabled by a waveguide hybrid photonic-plasmonic mode. This work represents a major advance toward the realization of application-oriented photonic circuits with integrated nanolaser sources.

Solvothermal synthesis, denoting chemical reactions occurring in metastable liquids above their boiling point, normally requires the use of a sealed autoclave under pressure to prevent the solvent from boiling. This work introduces an experimental approach that enables solvothermal synthesis at ambient pressure in an open reaction medium. The approach is based on the use of gold nanoparticles deposited on a glass substrate and acting as photothermal sources. To illustrate the approach, the selected hydrothermal reaction involves the formation of indium hydroxide microcrystals favored at 200 degrees C in liquid water. In addition to demonstrating the principle, the benefits and the specific characteristics of such an approach are investigated, in particular, the much faster reaction rate, the achievable spatial and time scales, the effect of microscale temperature gradients, the effect of the size of the heated area, and the effect of thermal-induced microscale fluid convection. This technique is general and could be used to spatially control the deposition of virtually any material for which a solvothermal synthesis exists