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Multiplexed surface plasmon imaging of serum biomolecules: Fe3O4@Au Core/shell nanoparticles with plasmonic simulation insights
摘要： Nano-biosensors that are not only sensitive and selective, but also enable multiplex detection of ultra-low levels of both large and small biomolecules in clinical sample matrices are essential for in vitro diagnostics. We present herein a multiplex surface plasmon microarray design that employs citrate-stabilized Fe3O4@Au core/shell nanoparticles (NPs) as the plasmon signal ampli?cation label for combined detection of serum proteins and nucleotide markers. The multiplex sensing is demonstrated using two interleukins (IL-6 and IL-8) and two microRNAs (miRNA-21 and miRNA-155) in 10% serum, which is clinically relevant than simple bu?er solution based biosensors. We observed that the surface plasmon signal change for larger proteins even at higher concentrations was less than the relatively smaller miRNA molecules. We draw two conclusions from this result: (i) the number of selectively bound analytes onto the sensor (i.e., antigen for an antibody or miRNA for a capture nucleotide) in?uences the signal change, and (ii) the extent of interaction of the detection probe carrying core/shell NP labels with the sensor surface plasmons in?uences the amount of signal change. Results indicate that both factors, (i) and (ii), are greater for small oligonucleotide hybridization assembly than a large sandwich protein immunoassembly. The core/shell NPs o?ered several fold enhanced sensitivity and wider dynamic range of detection over assays without using them. With recently growing attention on in vitro diagnostics for painless/minimally-invasive detection of diseases and abnormalities, ?ndings presented herein are important for designing novel multiplex biosensors for real sample analysis in complex matrices.
关键词： serum proteins,wide dynamic range,serum miRNAs,Multiplex imaging,core/shell nanoparticles,FDTD simulation
更新于2025-09-16 10:30:52
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Method for measuring main characteristics of electron-optical cameras
摘要： A procedure is described for determining the basic parameters of linear-sweep electron-optical cameras. The techniques are considered for measuring the limiting temporal resolution and dynamic range of the PS-1/S1 camera using a femtosecond laser and sinusoidal-modulated laser radiation.
关键词： temporal resolution,electron-optical camera,dynamic range,picosecond – femtosecond laser radiation
更新于2025-09-16 10:30:52
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Photodetector of Shortwave Infrared Range of Format 640 × 512 Elements with Increased Dynamic Range
摘要： The paper substantiates the necessity of expanding the dynamic range in a shortwave infrared (SWIR) photodetector (PD). The traditionally used methods have low efficiency, especially in large-format matrices with a step of not more than 15 μm. The greatest efficiency of expanding the dynamic range (up to 100 dB) is provided by accumulative cells with individually variable transfer characteristic depending on the brightness of the fragments of the observed scene. The paper proposes a simple, in topological implementation, and effective way of expanding the dynamic range based on the auto-tuning of accumulation time individually in each cell of the integrated reading circuit. At the same time, the high steepness and linearity of the transformation in the storage cells with moderate illumination (up to 50–70% of the maximum signal) remains, but the sensitivity in the cells close to saturation decreases. As a result, a linear-log transfer characteristic is formed, providing an extended dynamic range. The paper provides examples of images with an extended dynamic range obtained using the first domestic SWIR camera of format 640 × 512 elements.
关键词： photodiodes,InGaAs,LSI readout,shortwave infrared range,expansion of the dynamic range,photodetectors
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - The Photonic Guitar Pickup: A High-Sensitivity, High-Bandwidth Fiber Strain Sensor
摘要： The photonic guitar pickup: a high-sensitivity, high-bandwidth fiber strain sensor. Fiber-strain sensors have found numerous applications from structural health monitoring for vibrations, to pressure and temperature sensing. Many of these sensors exploit the strain-sensitivity of the reflection wavelength of fiber-bragg gratings, (cid:83)-shifted gratings or other waveguide devices. The strain is typically inferred from a change of reflected or transmitted light intensity. Light intensity measurements are not very robust and have an inherently limited accuracy. We propose that a frequency-based strain measurements using fiber Fabry-Perot (FFP) cavities provide not only superior sensitivity but also retain a very high measurement bandwidth. Here, we present a fiber optic vibration sensor based on an FFP cavity, which consists of a matched pair of 23 dB fiber Bragg gratings coupled to a custom-built signal processing circuit. The wavelength of a laser diode is locked to one of the many cavity resonances using the Pound–Drever–Hall scheme. We demonstrate that such a strain sensor has an ultrawide dynamic sensing range, from less than 1 Hz to clinical ultrasound frequencies near 6 MHz. Its linear sensitivity range extends from below 1 n(cid:72) to 2 (cid:80)(cid:72), and its dynamic response limit is as high as 12 m(cid:72)/s. To demonstrate the high fidelity of the strain measurements we attached the FFP cavity sensor to the top plate of an acoustic guitar and recorded several melodies. As expected the sensor system was largely immune to noise arising from optical intensity fluctuations. We made distortion-free audio recordings of musical pieces from infrasound (~8 Hz) to 30 kHz with a 50 dB dynamic range in acoustic power. The remaining noise in our measurements arises from electronic sources and not optical sources, giving hope that future developments may be able to further increase the dynamic range of the measurements, if needed. In separate experiments the same sensor was affixed to the rim of a wineglass and to the side of a steel cantilever to monitor the (photo-)acoustic response of these mechanical resonators to periodic photo-excitation. We found, for example, that the limit of detection for orthophosphate through the photoacoustic excitation of the respective molybdenum-blue complex was below 2 ppm. Finally, the sensor was embedded in tissue phantoms to validate that it accurately responds to low frequencies (heart beat) and high frequencies (ultrasound pulse). In its most recent version the laser driver and the PDH circuit are addressed through a Raspberry-Pi microcontroller, making the sensor system very compact and relatively inexpensive. We propose that sensor systems based on PDH-interrogated FFP-sensor heads are robust and versatile for a large variety of monitoring applications.
关键词： Fabry-Perot cavity,vibration sensor,dynamic range,Pound–Drever–Hall scheme,fiber strain sensor
更新于2025-09-11 14:15:04
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Optimizing the Nonlinearity and Dissipation of a SNAIL Parametric Amplifier for Dynamic Range
摘要： We present a quantum-limited Josephson-junction-based three-wave-mixing parametric amplifier, the superconducting nonlinear asymmetric inductive element (SNAIL) parametric amplifier (SPA), which uses an array of SNAILs as the source of tunable nonlinearity. We show how to engineer the nonlinearity over multiple orders of magnitude by varying the physical design of the device. As a function of design parameters, we systematically explore two important amplifier nonidealities that limit dynamic range: the phenomena of gain compression and intermodulation distortion, whose minimization are crucial for high-fidelity multiqubit readout. Through a comparison with first-principles theory across multiple devices, we demonstrate how to optimize both the nonlinearity and the input-output port coupling of these SNAIL-based parametric amplifiers to achieve higher saturation power, without sacrificing any other desirable characteristics. The method elaborated in our work can be extended to improve all forms of parametrically induced mixing that can be employed for quantum-information applications.
关键词： gain compression,Josephson-junction,three-wave-mixing,parametric amplifier,SNAIL,dynamic range,quantum-limited,intermodulation distortion
更新于2025-09-11 14:15:04
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All-optical Multi-Octave Microwave Phase Shifter
摘要： In wideband multi-octave phase-shifting photonic links, second-order distortions (SDs) overlap with fundamental signals and cannot be filtered out. In this paper, we propose an all-optical microwave phase shifter, which suppresses the SDs and supports the amplitude tuning of the fundamental signals. The proposed all-optical phase shifter is based on polarization modulation and differential detection. Thanks to the all-optical techniques, maximum operating frequency of the proposed phase shifter is not limited by electronic bottlenecks. By using polarization modulation, the phase and amplitude of the output fundamental signals are tuned by simply manipulating the polarization states of the optical signals. By using differential detection, SDs components with same frequencies cancel out each other. Simulation results show that phase shift of 360° and power adjustable extent over 21.41 dB for the output fundamental signals are achieved. The direct current (DC) and the SDs components are well suppressed after differential detection. The typical spurious free dynamic range (SFDR) is significant improved by 21.79 dB from 77.78 dB·Hz1/2 to 99.57 dB·Hz2/3.
关键词： differential detection,polarization modulation,spurious free dynamic range,second-order distortions,Phase shift
更新于2025-09-10 09:29:36
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Microwave Photonic Link With Improved Dynamic Range Through π phase Shift of the Optical Carrier Band
摘要： A microwave photonic link (MPL) with an improved spurious-free dynamic range (SFDR) by introducing a π phase shift to the spectral complements in the optical carrier band (OCB) is proposed and experimentally demonstrated. The fundamental concept to improve the SFDR is to suppress the third-order intermodulation distortion (IMD3) terms while retaining a high gain for the fundamental terms, which is achieved by introducing a π phase shift to the OCB with the joint use of an electrical 90? hybrid coupler and a dual-parallel Mach-Zehnder modulator (DP-MZM). When detecting the optical signal from the DP-MZM at a photodetector (PD), the IMD3 components originated from the beating between different optical sidebands can be fully cancelled, while the gain for the fundamental terms remains reasonably high. Therefore, the SFDR of the MPL is significantly increased. The proposed MPL is experimentally demonstrated. An SFDR of 108.1 dB?Hz2/3 or 120.4 dB?Hz2/3 for a noise floor of -146.9 or -163.9 dBm/Hz is achieved, which is 14 dB or 15 dB higher than that of a conventional intensity-modulation direct-detection (IMDD) MPL.
关键词： parallel intensity modulators,third-order intermodulation,microwave photonic link (MPL),Spurious-free dynamic range (SFDR)
更新于2025-09-10 09:29:36
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Engineering Improved Photoswitches for the Control of Nucleocytoplasmic Distribution
摘要： Optogenetic techniques use light-responsive proteins to study dynamic processes in living cells and organisms. These techniques typically rely on repurposed naturally occurring light-sensitive proteins to control sub-cellular localization and activity. We previously engineered two optogenetic systems, the Light Activated Nuclear Shuttle (LANS) and the Light-Inducible Nuclear eXporter (LINX), by embedding nuclear import or export sequence motifs into the C-terminal helix of the light-responsive LOV2 domain of Avena sativa phototropin 1, thus enabling light-dependent trafficking of a target protein into and out of the nucleus. While LANS and LINX are effective tools, we posited that mutations within the LOV2 hinge-loop, which connects the core PAS domain and the C-terminal helix, would further improve the functionality of these switches. Here, we identify hinge-loop mutations that favourably shift the dynamic range (the ratio of the on- to off-target subcellular accumulation) of the LANS and LINX photoswitches. We demonstrate the utility of these new optogenetic tools to control gene transcription and epigenetic modifications, thereby expanding the optogenetic ‘tool kit’ for the research community.
关键词： LANS,LINX,LOV2,dynamic range,Optogenetics,nucleocytoplasmic shuttle
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - High Dynamic Range Infrared Sensors for Remote Sensing Applications
摘要： In this presentation, we will report our recent efforts in achieving high performance in Antimonides type-II superlattice (T2SL) based infrared photodetectors using the barrier infrared detector (BIRD) architecture. The recent emergence of barrier infrared detectors such as the nBn [1] and the XBn [2] have resulted in mid-wave infrared (MWIR) and long-wave infrared (LWIR) detectors with substantially higher operating temperatures than previously available in III-V semiconductor based MWIR and LWIR detectors. The initial nBn devices used either InAs absorber grown on InAs substrate, or lattice-matched InAsSb alloy grown on GaSb substrate, with cutoff wavelengths of ~3.2 μm and ~4 μm, respectively. While these detectors could operate at much higher temperatures than existing MWIR detectors based on InSb, their spectral responses do not cover the full (3 – 5.5 μm) MWIR atmospheric transmission window. There also have been nBn detectors based on the InAs/GaSb T2SL absorber [3,4].
关键词： infrared detector,focal plane array,type-II superlattice,high dynamic range,high quantum efficiency
更新于2025-09-10 09:29:36
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7.4: Visual Fatigue during Viewing High-Dynamic Range Display
摘要： The visual fatigue caused by one hour’s viewing of High-Dynamic Range (HDR) and Standard-Dynamic Range (SDR) display has been through subjective reports, ophthalmological parameters and physiological signals. The results show that visual fatigue becomes more serious with increasing time under the two modes. Compared to SDR display, one hour of viewing HDR display produces significantly greater tired eyes symptom and low frequency power (LF) of heart rate variability.
关键词： High-Dynamic Range display,Standard-Dynamic Range display,visual fatigue,visual fatigue indicator
更新于2025-09-09 09:28:46