Contactless Gait Assessment in Home-like Environments

Gait analysis is an important part of assessments for a variety of health conditions, specifically neurodegenerative diseases. Currently, most methods for gait assessment are based on manual scoring of certain tasks or restrictive technologies. We present an unobtrusive sensor system based on light detection and ranging sensor technology for use in home-like environments. In our evaluation, we compared six different gait parameters, based on recordings from 25 different people performing eight different walks each, resulting in 200 unique measurements. We compared the proposed sensor system against two state-of-the art technologies, a pressure mat and a set of inertial measurement unit sensors. In addition to test usability and long-term measurement, multi-hour recordings were conducted. Our evaluation showed very high correlation (r>0.95) with the gold standards across all assessed gait parameters except for cycle time (r=0.91). Similarly, the coefficient of determination was high (R2>0.9) for all gait parameters except cycle time. The highest correlation was achieved for stride length and velocity (r≥0.98,R2≥0.95). Furthermore, the multi-hour recordings did not show the systematic drift of measurements over time. Overall, the unobtrusive gait measurement system allows for contactless, highly accurate long- and short-term assessments of gait in home-like environments

Development and evaluation of a new virtual reality-based audio-tactile cueing-system to guide visuo-spatial attention

Spatial attention is an important feature for filtering everyday inputs. The direction of the attention can be guided by the use of visual, auditory or tactile stimuli. The literature regarding the effect of cueing spatial attention in visual search tasks consistently shows an improvement in accuracy and reaction time. So far, most studies have used two-dimensional setups, for which ecological validity may be questioned. In this study with healthy participants, we investigated the feasibility of a virtual reality-based setup. We examined the feasibility and compared the performance in a visual search task as auditory, tactile or combined cues were given. The results revealed high usability and a significantly higher detection rate for combined audio-tactile cues compared to auditory cues alone

Observation of stimulated Brillouin scattering in silicon nitride integrated waveguides

We report the first observation of backward stimulated Brillouin scattering in fully cladded Si3N4 waveguides. The intrinsic Brillouin gain at 25 GHz and the photoelastic constant are estimated to be 4 × 10−13 m/W and |p12| = 0.047 ± 0.004 respectively

Observation of Stimulated Brillouin Scattering in Silicon Nitride Integrated Waveguides

Silicon nitride (Si3N4) has emerged as a promising material for integrated nonlinear photonics and has been used for broadband soliton microcombs and low-pulse-energy supercontinuum generation. Therefore, understanding all nonlinear optical properties of Si3N4 is important. So far, only stimulated Brillouin scattering (SBS) has not yet been reported. Here we observe, for the first time, backward SBS in fully cladded Si3N4 waveguides. The Brillouin gain spectrum exhibits an unusual multipeak structure resulting from hybridization with high-overtone bulk acoustic resonances of the silica cladding. The reported intrinsic Si3N4 Brillouin gain at 25 GHz is estimated as 4×10−13  m/W. Moreover, the magnitude of the Si3N4 photoelastic constant is estimated as |p12|=0.047±0.004, which is nearly 6 times smaller than for silica. Since SBS imposes an optical power limitation for waveguides, our results explain the capability of Si3N4 to handle high optical power, central for integrated nonlinear photonics

2023 roadmap for materials for quantum technologies

Quantum technologies are poised to move the foundational principles of quantum physics to the forefront of applications. This roadmap identifies some of the key challenges and provides insights on material innovations underlying a range of exciting quantum technology frontiers. Over the past decades, hardware platforms enabling different quantum technologies have reached varying levels of maturity. This has allowed for first proof-of-principle demonstrations of quantum supremacy, for example quantum computers surpassing their classical counterparts, quantum communication with reliable security guaranteed by laws of quantum mechanics, and quantum sensors uniting the advantages of high sensitivity, high spatial resolution, and small footprints. In all cases, however, advancing these technologies to the next level of applications in relevant environments requires further development and innovations in the underlying materials. From a wealth of hardware platforms, we select representative and promising material systems in currently investigated quantum technologies. These include both the inherent quantum bit systems and materials playing supportive or enabling roles, and cover trapped ions, neutral atom arrays, rare earth ion systems, donors in silicon, color centers and defects in wide-band gap materials, two-dimensional materials and superconducting materials for single-photon detectors. Advancing these materials frontiers will require innovations from a diverse community of scientific expertise, and hence this roadmap will be of interest to a broad spectrum of disciplines