With the rapid advances in wearable electronics and photonics, self-sustainable wearable systems are desired to increase service life and reduce maintenance frequency. Triboelectric technology stands ...out as a promising versatile technology due to its flexibility, self-sustainability, broad material availability, low cost, and good scalability. Various triboelectric–human–machine interfaces (THMIs) have been developed including interactive gloves, eye blinking/body motion-triggered interfaces, voice/breath monitors, and self-induced wireless interfaces. Nonetheless, THMIs conventionally use electrical readout and produce pulse-like signals due to the transient charge flows, leading to unstable and lossy transfer of interaction information. To address this issue, we propose a strategy by equipping THMIs with robust nanophotonic aluminum nitride (AlN) modulators for readout. The electrically capacitive nature of AlN modulators enables THMIs to work in the open-circuit condition with negligible charge flows. Meanwhile, the interaction information is transduced from THMIs’ voltage to AlN modulators’ optical output via the electro-optic Pockels effect. Thanks to the negligible charge flow and the high-speed optical information carrier, stable, information-lossless, and real-time THMIs are achieved. Leveraging the design flexibility of THMIs and nanophotonic readout circuits, various linear sensitivities independent of force speeds are achieved in different interaction force ranges. Toward practical applications, we develop a smart glove to realize continuous real-time robotics control and virtual/augmented reality interaction. Our work demonstrates a generic approach for developing self-sustainable HMIs with stable, information-lossless, and real-time features for wearable systems.
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IJS, KILJ, NUK, PNG, UL, UM
A positive leadership style can promote work engagement. Using social exchange theory, this study examines the impact of employee leadership styles on work engagement. In addition, the link also ...considered the mitigating role of trust in leaders. Preliminary data were collected from the educational and non-educational staff of the Business Management Sciences and Education Department at different universities. We collected responses from 242 employees from selected universities using the purposive sampling technique. We tested the proposed hypothesis using linear regression. Research has shown that there is a positive link between employee leadership and work engagement. When trust in leaders as facilitators was introduced, the relationship between leadership and work engagement was relaxed to increase trust in leaders. Practical and theoretical contributions to the study were provided with recommendations for further study.
The surface-enhanced infrared absorption (SEIRA) technique has been focusing on the metallic resonator structures for decades, exploring different approaches to enhance sensitivity. Although the high ...enhancement is achieved, the dissipative loss and strong heating are the intrinsic drawbacks of metals. Recently, the dielectric platform has emerged as a promising alternative. In this work, we report a guided resonance-based all-dielectric photonic crystal slab as the platform for SEIRA. The guided resonance-induced enhancement in the effective path length and electric field, together with gas enrichment polymer coating, leads to a detection limit of 20 ppm in carbon dioxide (CO2) sensing. This work explores the feasibility to apply low loss all-dielectric structures as a surface enhancement method in the transmission mode.
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In this paper, a single-pixel hyperspectral imager is developed based on the Hadamard transformation. The imager’s design, fabrication, signal processing method, and experimental results are ...discussed. The single-pixel hyperspectral imager works in pushbroom mode and employs both spatial encoding and spectral encoding to acquire the hyperspectral data cube. Hadamard encoding patterns, which are known for their multiplexing advantage to achieve high signal-to-noise ratio (SNR), are used in both encoding schemes. A digital micromirror device (DMD) from Texas Instruments (TI) is used for slow spatial encoding and a resonant scanning mirror in combination with a fixed Hadamard mask is used for fast spectral encoding. In addition, the pushbroom operation can be achieved internally by spatially shifting the location of the Hadamard encoded slit on the DMD, thus the imager is able to acquire 3D data cubes without the need to scan it across the object. Although our experimental results demonstrate the hyperspectral data cubes of various objects over a 450 nm ∼ 750 nm visible spectral range, the proposed imager can be easily configured to be used at other wavelengths due to the single-pixel detection mechanism used.
In recent years, there has been growing interest in optical sensors based on microcavities due to their advantages of size reduction and enhanced sensing capability. In this paper, we aim to give a ...comprehensive review of the field of photonic crystal nanobeam cavity-based sensors. The sensing principles and development of applications, such as refractive index sensing, nanoparticle sensing, optomechanical sensing, and temperature sensing, are summarized and highlighted. From the studies reported, it is demonstrated that photonic crystal nanobeam cavities, which provide excellent light confinement capability, ultra-small size, flexible on-chip design, and easy integration, offer promising platforms for a range of sensing applications.
Optomechanical sensing based on the coupling between mechanical motions and optical resonances has attracted huge interest in sensor applications due to its small footprint, high sensitivity, low ...detection limit, and electromagnetic immunity. Optomechanical sensors that detect from mechanical motion at µm scale to molecular vibration at nm scale have found various applications such as force, inertia, acoustic, chemical, and thermal sensing, etc. In this review, we provide an overview of the recent progress of optomechanical sensors. Three development fields of optomechanical sensors are reviewed, which are passive optomechanical sensors, electro-optomechanical sensing platforms, and molecular vibration sensing schemes. The sensor configurations, applications, and integrations are described. In the end, we also provide our perspectives on the future development directions of optomechanical sensors.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
With the development of silicon photonics, dense photonic integrated circuits play a significant role in applications such as light detection and ranging systems, photonic computing accelerators, ...miniaturized spectrometers, and so on. Recently, extensive research work has been carried out on the phase shifter, which acts as the fundamental building block in the photonic integrated circuit. In this review, we overview different types of silicon photonic phase shifters, including micro-electro-mechanical systems (MEMS), thermo-optics, and free-carrier depletion types, highlighting the MEMS-based ones. The major working principles of these phase shifters are introduced and analyzed. Additionally, the related works are summarized and compared. Moreover, some emerging applications utilizing phase shifters are introduced, such as neuromorphic computing systems, photonic accelerators, multi-purpose processing cores, etc. Finally, a discussion on each kind of phase shifter is given based on the figures of merit.
Spectrometers are key instruments in diverse fields, notably in medical and biosensing applications. Recent advancements in nanophotonics and computational techniques have contributed to new ...spectrometer designs characterized by miniaturization and enhanced performance. This paper presents a comprehensive review of miniaturized computational spectrometers (MCS). We examine major MCS designs based on waveguides, random structures, nanowires, photonic crystals, and more. Additionally, we delve into computational methodologies that facilitate their operation, including compressive sensing and deep learning. We also compare various structural models and highlight their unique features. This review also emphasizes the growing applications of MCS in biosensing and consumer electronics and provides a thoughtful perspective on their future potential. Lastly, we discuss potential avenues for future research and applications.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A miniature solid-state varifocal lens based on Alvarez principle with lens elements having free-form surfaces is reported. The Alvarez lens elements are implemented with diamond-turning and ...replication molding processes. They are integrated with electrostatically-driven MEMS comb-drive actuators fabricated using SOI micromachining. Dynamic tuning of focal length more than 1.5 times (from 3 mm to 4.65 mm) is experimentally demonstrated with only small MEMS-driven lateral movements of 40 μm. Such varifocal lens may be useful in miniature cameras for autofocus and zooming due to its advantages including ease of packaging and fast tuning speed.
A new class of hybrid systems that couple optical and mechanical nanoscale devices is under development. According to their interaction concepts, two groups of opto-mechanical systems are summarized ...as mechanically tunable and radiation pressure-driven optical resonators. On account of their high-quality factors and small mode volumes as well as good on-chip integrability with waveguides/circuits, photonic crystal (PhC) cavities have attracted great attention in sensing applications. Benefitting from the opto-mechanical interaction, a PhC cavity integrated opto-mechanical system provides an attractive platform for ultrasensitive sensors to detect displacement, mass, force, and acceleration. In this review, we introduce basic physical concepts of opto-mechanical PhC system and describe typical experimental systems for sensing applications. Opto-mechanical interaction-based PhC cavities offer unprecedented opportunities to develop lab-on-a-chip devices and witness a promising prospect to further manipulate light propagation in the nanophotonics.
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