Towards fully integrated photonic displacement sensors

Funding: European Union Horizon 2020 research and innovation programme under the Future and Emerging Technologies Open grant agreement Super-pixels No 829116.The field of optical metrology with its high precision position, rotation and wavefront sensors represents the basis for lithography and high resolution microscopy. However, the on-chip integration a task highly relevant for future nanotechnological devices necessitates the reduction of the spatial footprint of sensing schemes by the deployment of novel concepts. A promising route towards thisgoal is predicated on the controllable directional emission of the fundamentally smallest emitters of light, i.e. dipoles, as an indicator. Here we realize an integrated displacement sensor based on the directional emission of Huygens dipoles excited in an individual dipolar antenna. The position of the antenna relative to the excitation field determines its directional coupling into a six-way crossing of photonic crystal waveguides. In our experimental study supported by theoretical calculations, we demonstrate the first prototype of an integrated displacement sensor with a standard deviation of the position accuracy below λ=300 at room temperature and ambient conditions.Publisher PDFPeer reviewe

Principles for developing benchmark criteria for staff training in responsible gambling

One approach to minimizing the negative consequences of excessive gambling is staff training to reduce the rate of the development of new cases of harm or disorder within their customers. The primary goal of the present study was to assess suitable benchmark criteria for the training of gambling employees at casinos and lottery retailers. The study utilised the Delphi Method, a survey with one qualitative and two quantitative phases. A total of 21 invited international experts in the responsible gambling field participated in all three phases. A total of 75 performance indicators were outlined and assigned to six categories: (1) criteria of content, (2) modelling, (3) qualification of trainer, (4) framework conditions, (5) sustainability and (6) statistical indicators. Nine of the 75 indicators were rated as very important by 90 % or more of the experts. Unanimous support for importance was given to indicators such as (1) comprehensibility and (2) concrete action-guidance for handling with problem gamblers, Additionally, the study examined the implementation of benchmarking, when it should be conducted, and who should be responsible. Results indicated that benchmarking should be conducted every 1–2 years regularly and that one institution should be clearly defined and primarily responsible for benchmarking. The results of the present study provide the basis for developing a benchmarking for staff training in responsible gambling

Hybrid-Entanglement in Continuous Variable Systems

Entanglement is one of the most fascinating features arising from quantum-mechanics and of great importance for quantum information science. Of particular interest are so-called hybrid-entangled states which have the intriguing property that they contain entanglement between different degrees of freedom (DOFs). However, most of the current continuous variable systems only exploit one DOF and therefore do not involve such highly complex states. We break this barrier and demonstrate that one can exploit squeezed cylindrically polarized optical modes to generate continuous variable states exhibiting entanglement between the spatial and polarization DOF. We show an experimental realization of these novel kind of states by quantum squeezing an azimuthally polarized mode with the help of a specially tailored photonic crystal fiber

Experimental cross-polarization detection of coupling far-field light to highly confined plasmonic gap modes via nanoantennas

We experimentally demonstrate the coupling of far-field light to highly confined plasmonic gap modes via connected nanoantennas. The excitation of plasmonic gap modes is shown to depend on the polarization, position and wavelength of the incident beam. Far-field measurements performed in crossed polarization allow for the detection of extremely weak signals re-emitted from gap waveguides and can increase the signal-to-noise ratio dramatically.Comment: 5 figures; http://apl.aip.org

Hybrid Orthorhombic Carbon Flakes Intercalated with Bimetallic Au-Ag Nanoclusters: Influence of Synthesis Parameters on Optical Properties

Until recently, planar carbonaceous structures such as graphene did not show any birefringence under normal incidence. In contrast, a recently reported novel orthorhombic carbonaceous structure with metal nanoparticle inclusions does show intrinsic birefringence, outperforming other natural orthorhombic crystalline materials. These flake-like structures self-assemble during a laser-induced growth process. In this article, we explore the potential of this novel material and the design freedom during production. We study in particular the dependence of the optical and geometrical properties of these hybrid carbon-metal flakes on the fabrication parameters. The influence of the laser irradiation time, concentration of the supramolecular complex in the solution, and an external electric field applied during the growth process are investigated. In all cases, the self-assembled metamaterial exhibits a strong linear birefringence in the visible spectral range, while the wavelength-dependent attenuation was found to hinge on the concentration of the supramolecular complex in the solution. By varying the fabrication parameters one can steer the shape and size of the flakes. This study provides a route towards fabrication of novel hybrid carbon-metal flakes with tailored optical and geometrical properties

Strong, spectrally-tunable chirality in diffractive metasurfaces

The authors acknowledge the support of the Canada Excellence Research Chairs Program. P.B. acknowledges the support from the Alexander von Humboldt Foundation.Metamaterials and metasurfaces provide a paradigm-changing approach for manipulating light. Their potential has been evinced by recent demonstrations of chiral responses much greater than those of natural materials. Here, we demonstrate theoretically and experimentally that the extrinsic chiral response of a metasurface can be dramatically enhanced by near-field diffraction effects. At the core of this phenomenon are lattice plasmon modes that respond selectively to the illumination’s polarization handedness. The metasurface exhibits sharp features in its circular dichroism spectra, which are tunable over a broad bandwidth by changing the illumination angle over a few degrees. Using this property, we demonstrate an ultra-thin circular-polarization sensitive spectral filter with a linewidth of ~10 nm, which can be dynamically tuned over a spectral range of 200 nm. Chiral diffractive metasurfaces, such as the one proposed here, open exciting possibilities for ultra-thin photonic devices with tunable, spin-controlled functionality.Publisher PDFPeer reviewe

Spatially resolving amplitude and phase of light with a reconfigurable photonic integrated circuit

Photonic integrated circuits (PICs) play a pivotal role in many applications. Particularly powerful are circuits based on meshes of reconfigurable Mach-Zehnder interferometers as they enable active processing of light. Various possibilities exist to get light into such circuits. Sampling an electromagnetic field distribution with a carefully designed free-space interface is one of them. Here, a reconfigurable PIC is used to optically sample and process free-space beams so as to implement a spatially resolving detector of amplitudes and phases. In order to perform measurements of this kind we develop and experimentally implement a versatile method for the calibration and operation of such integrated photonics based detectors. Our technique works in a wide parameter range, even when running the chip off the design wavelength. Amplitude, phase and polarization sensitive measurements are of enormous importance in modern science and technology, providing a vast range of applications for such detectors

The photonic wheel - demonstration of a state of light with purely transverse angular momentum

In classical mechanics, a system may possess angular momentum which can be either transverse (e.g. in a spinning wheel) or longitudinal(e.g. for a spiraling seed falling from a tree) with respect to the direction of motion. However, for light, a typical massless wave system,the situation is less versatile. Photons are well-known to exhibit intrinsic angular momentum which is longitudinal only: the spin angularmomentum defining the polarization and the orbital angular momentum associated with a spiraling phase front. Here we show that itis possible to generate a novel state of the light field that contains purely transverse angular momentum, the analogue of a spinningmechanical wheel. We realize this state by tight focusing of a polarization tailored light beam and measure it using an optical nano-probingtechnique. Such a novel state of the light field can find applications in optical tweezers and spanners where it allows for additionalrotational degree of freedom not achievable in single-beam configurations so far

Improvements in Chilean patients with obesity following a 5-month multidisciplinary exercise program: A feasibility study

Background: The aim of this study was to determine the effects of a multidisciplinary exercise program on physical fitness, metabolic profile and nutritional status of obese patients. Methods: Seventeen women and four men (N.=21, age 18 to 60 years), with severe obesity (BMI=35-40 kg/m2, N.=7), morbid obesity (BMI=40-50 kg/m2, N.=9), and super obesity (BMI>50 kg/m2, N.=5), took part in a physical exercise program with nutritional and psychological support. The intermittent physical exercise program was applied three times per week (1 hour/session), with 4-8 exercises with weights. Three series were carried out for 60 s each, with increasing intensity leading to exhaustion at the end of the period and with 1-2 min recovery between series. Outcomes include the BMI, waist contour, blood pressure, cardiorespiratory fitness, exercise capacity, maximum dynamic strength, hand grip strength, basal glucose and lipid profiles. Results: The patients decreased in weight and BMI (P<0.05). Morbid (N.=9) and super obese (N.=5) improved their cardiorespiratory fitness (P=0.005 and 0.040) and lowered their triglycerides (-25.70% and -15.38%; P=0.008). Hand grip strength improved in the super obese (P<0.001). Descriptively, patients with super obesity had the largest improvements. Conclusions: Multi-modal lifestyle and exercise interventions improve the condition especially in super obese patients. The improved health status may improve the outcome of secondary steps in weight loss, such as bariatric surgery. The program was feasible to be executed and patients compliant to the intervention