| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Cao, Shun, et al.
(författare)
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Strong Coupling between a Single Quantum Emitter and a Plasmonic Nanoantenna on a Metallic Film
- 2022
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Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- The strong coupling between single quantum emitters and resonant optical micro/nanocavities is beneficial for understanding light and matter interactions. Here, we propose a plasmonic nanoantenna placed on a metal film to achieve an ultra-high electric field enhancement in the nanogap and an ultra-small optical mode volume. The strong coupling between a single quantum dot (QD) and the designed structure is investigated in detail by both numerical simulations and theoretical calculations. When a single QD is inserted into the nanogap of the silver nanoantenna, the scattering spectra show a remarkably large splitting and anticrossing behavior of the vacuum Rabi splitting, which can be achieved in the scattering spectra by optimizing the nanoantenna thickness. Our work shows another way to enhance the light/matter interaction at a single quantum emitter limit, which can be useful for many nanophotonic and quantum applications.
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| 3. |
- He, Nan, et al.
(författare)
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High-Speed Duplex Free Space Optical Communication System Assisted by a Wide-Field-of-View Metalens
- 2023
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 10:9, s. 3052-3059
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Tidskriftsartikel (refereegranskat)abstract
- Free space optical communication (FSO) has gained significant attention due to the growing demand for a high information capacity. For FSO between multiple or moving targets, a receiver with a wide angle of acquisition capability is necessary. Traditionally, gimbals and fast steering mirrors have been used, but they are often difficult to make both compact and wide-angle. Here, a novel duplex FSO system is demonstrated, which utilizes a highly compact fiber coupling metalens to receive and transmit signals in a large field of view up to 80°. High coupling efficiency up to 48.8% at a wavelength of 1550 nm is experimentally achieved. The small coupling loss enables the user to modulate and direct the downstream power from the base station back along the same path, saving energy and leaving only one source in the FSO system. The low bit error rate and the open and clear eye diagram results validate the excellent downlink/uplink communication performance of a 10 Gbps FSO system empowered by the metalens. The system exhibits a large field of view, high data rate, compact size, and low power consumption, which meets the size, weight, and power requirement of smart devices.
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| 4. |
- Lin, Huagang, et al.
(författare)
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Polymer-based planar waveguide chirped Bragg grating for high-resolution tactile sensing
- 2022
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 30:12, s. 20871-20882
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Tidskriftsartikel (refereegranskat)abstract
- A novel tactile sensor for two-dimensional force location measurements, based on polymer-based planar waveguide chirped Bragg gratings (PPCBGs) fabricated on sheet PMMA substrate, is presented. The planar waveguide and chirped Bragg grating are simultaneously generated using a KrF excimer laser and a phase mask covered by a quartz chrome mask. Location and magnitude of an applied force is measured by observing the change of the wavelength of a dip in the measured spectrum and a change in the reflectivity intensity. Experimental characterization indicates submillimeter spatial resolution of applied force in the range of 1-4 N with a sensitivity of 947.02 pm/mm.
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| 5. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 6. |
- Sun, Yuwei, et al.
(författare)
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Enhancing Circularly Polarized Emission by a Planar Chiral Dielectric Metasurface
- 2023
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Ingår i: Advanced Optical Materials. - : Wiley. - 2162-7568 .- 2195-1071. ; 11:14
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Tidskriftsartikel (refereegranskat)abstract
- Circularly polarized emission (CPE) has attracted great interest in optoelectronics, biosensing, etc. Here, a resonant planar chiral dielectric metasurface that can be constructed to provide a preferable way for CPE is demonstrated. The planar metasurface is easy to fabricate, and the corresponding far-field circular polarization degree is extremely high and angle-insensitive. The designed metasurface is made of a periodic array of in-plane mirror-asymmetric silicon pillar dimers and supports a low-leakage chiral band-edge mode. Experimentally, the photoluminescence of a thin film of PbS/CdS quantum dots coated on such a metasurface is enhanced by 57 times with the far-field degree of circular polarization as high as 0.74. The planar platform provides a flexible and efficient way for manipulating CPE, in which other periodic coupling effects may also be adopted to enhance the light–matter interaction, such as quasi-bound states in the continuum and lattice resonance.
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| 7. |
- Xing, Yuxin, et al.
(författare)
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FireNose on Mobile Robot in Harsh Environments
- 2019
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Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X .- 1558-1748. ; 19:24, s. 12418-12431
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present a novel multi-sensor unit, a.k.a. FireNose, to detect and discriminate both known and unknown gases in uncontrolled conditions to aid firefighters under harsh conditions. The unit includes three metal oxide (MOX) gas sensors with CMOS micro heaters, a plasmonic enhanced non-dispersive infrared (NDIR) sensor optimized for the detection of CO2, a commercial temperature humidity sensor, and a flow sensor. We developed custom film coatings for the MOX sensors (SnO2, WO3 and NiO) which greatly improved the gas sensitivity, response time and lifetime of the miniature devices. Our proposed system exhibits promising performance for gas sensing in harsh environments, in terms of power consumption (∼ 35 mW at 350°C per MOX sensor), response time (<10 s), robustness and physical size. The sensing unit was evaluated with plumes of gases in both, a laboratory setup on a gas testing rig and on-board a mobile robot operating indoors. These high sensitivity, high-bandwidth sensors, together with online unsupervised gas discrimination algorithms, are able to detect and generate their spatial distribution maps accordingly. In the robotic experiments, the resulting gas distribution maps corresponded well to the actual location of the sources. Therefore, we verified its ability to differentiate gases and generate gas maps in real-world experiments.
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| 8. |
- Xing, Yuxin, et al.
(författare)
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Mobile robot multi-sensor unit for unsupervised gas discrimination in uncontrolled environments
- 2017
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Ingår i: IEEE SENSORS 2017. - New York : Institute of Electrical and Electronics Engineers (IEEE). - 9781509010127 - 9781509010134 ; , s. 1691-1693
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Konferensbidrag (refereegranskat)abstract
- In this work we present a novel multi-sensor unit to detect and discriminate unknown gases in uncontrolled environments. The unit includes three metal oxide (MOX) sensors with CMOS micro heaters, a plasmonic enhanced non-dispersive infra-red (NDIR) sensor, a commercial temperature humidity sensor, and a flow sensor. The proposed sensing unit was evaluated with plumes of gases (propanol, ethanol and acetone) in both, a laboratory setup on a gas testing bench and on-board a mobile robot operating in an indoor workshop. It offers significantly improved performance compared to commercial systems, in terms of power consumption, response time and physical size. We verified the ability to discriminate gases in an unsupervised manner, with data collected on the robot and high accuracy was obtained in the classification of propanol versus acetone (96%), and ethanol versus acetone (90%).
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| 9. |
- Zhang, Zhi, et al.
(författare)
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Customized Structural Color Filters by Pixel-Level Electrothermal Regulation
- 2023
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Ingår i: Laser & Photonics reviews. - : Wiley. - 1863-8880 .- 1863-8899. ; 17:5
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Tidskriftsartikel (refereegranskat)abstract
- Reflective structural colors have backlight-free supremacy and can provide energy-efficient and environmental-friendly color production for many applications. However, they are hindered by the complex process and incorrect colors after fabrication. Here, a pixelated electrothermal oxidation technique is proposed that can precisely tailor and produce reflective structural colors covering the entire visible range, providing the possibility for customized structural color filter arrays from a titanium canvas. Furthermore, as a demonstration, a photonic-firework-like color filter array is achieved in a single step via thermal engineering. Based on this one-step-forming color array, a computational spectrometer is also realized featuring a resolvability of 10 nm and operating bandwidth covering the whole visible range. Considering its compactness and mass production capability, this method has numerous potential applications in, e.g., imaging, anti-counterfeiting, printing, color display, and spectroscopy.
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