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- 2018
- contrast stretch
- CMOS image sensor
- point-of-care (POC) diagnosis
- bio-microfluidic imaging
- Optoelectronic Information Science and Engineering
- Xi’an University of Technology
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Enhanced optical Kerr nonlinearity of graphene/Si hybrid waveguide
摘要: In this work, we experimentally study the optical Kerr nonlinearities of graphene/Si hybrid waveguides with enhanced self-phase modulation. In the case of CMOS compatible materials for nonlinear optical signal processing, Si and silicon nitride waveguides have been extensively investigated over the past decade. However, Si waveguides exhibit strong two-photon absorption (TPA) at telecommunication wavelengths, which leads to a signi?cant reduction of the nonlinear ?gure-of-merit (FOM). In contrast, a silicon nitride based material system usually suppresses the TPA but simultaneously leads to the reduction of Kerr nonlinearity by one order of magnitude. Here, we introduce a graphene/Si hybrid waveguide, which maintains the optical properties and CMOS compatibility of Si waveguides, while enhancing the Kerr nonlinearity, by transferring over to the top of the waveguides. The graphene/Si waveguides are measured to have an enhanced nonlinear parameter of 510 W(cid:2)1 m(cid:2)1, compared with that of the Si waveguide of 150 W(cid:2)1 m(cid:2)1. An enhanced nonlinear FOM of 2.48 6 0.25 has been achieved, which is four times larger than that of the Si waveguide of 0.6 6 0.1. This work reveals the potential application of graphene/Si hybrid waveguides with high Kerr nonlinearity and FOM for nonlinear all-optical signal processing.
关键词: nonlinear all-optical signal processing,graphene/Si hybrid waveguide,optical Kerr nonlinearity,CMOS compatible,self-phase modulation
更新于2025-11-28 14:23:57
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Triple-Junction Optoelectronic Sensor with Nanophotonic Layer Integration for Single Molecule Level Decoding
摘要: Interest in developing a rapid and robust DNA sequencing platform has surged over the past decade. Various next-/third-generation sequencing mechanisms have been employed to replace the traditional Sanger sequencing method. In sequencing by synthesis (SBS), a signal is monitored by a scanning charge-coupled device (CCD) to identify thousands to millions of incorporated dNTPs with distinctive fluorophores on a chip. Because one reaction site usually occupies dozens of pixels on a CCD detector, a bottleneck related to the bandwidth of CCD imaging limits the throughputs of the sequencing performance and causes tradeoffs among speed, accuracy, read length, and the numbers of reaction sites in parallel. Thus, current research aims to align one reaction site to a few pixels by directly stacking nanophotonic layers (NPLs) onto a CMOS detector to minimize the size of the sequencing platforms and accelerate the processing procedures. This article reports a custom integrated optoelectronic device based on a triple-junction photodiode (TPD) CMOS sensor in conjunction with NPL integration for real-time illumination and detection of fluorescent molecules.
关键词: planar waveguide,nanophotonic layer,CMOS,triple-junction photodiode (TPD),filter,grating
更新于2025-11-25 10:30:42
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TiO <sub/>2</sub> metasurfaces: From visible planar photonics to photochemistry
摘要: TiO2 metasurfaces have been intensively studied in the past few years. To date, the TiO2 metadevices only used their high reflective index (n). The controllable light extinction coefficient (k) of TiO2 has not been exploited yet. Here, we converted TiO2 metasurfaces to black TiO2 metasurfaces and explored their new opportunities in photochemistry. A complementary metal oxide semiconductor (CMOS)–compatible technique has been developed to reversibly and precisely control the absorption of TiO2 metasurfaces without spoiling their internal nanostructures. Consequently, two types of black TiO2 metasurfaces were realized for photochemical experiments. The metasurface with an ultrawide absorption band can substantially enhance the white light absorption and accelerate the solar-based photochemistry process by a factor of 18.7. The other metasurface with an absorption band of <20 nm only responded to the resonant wavelengths, making the photochemistry process capable of being monitored in real time. In addition, the reversible switch between normal and black states makes TiO2 metasurfaces suitable for dynamic metadevices as well.
关键词: photochemistry,CMOS-compatible technique,black TiO2,dynamic metadevices,TiO2 metasurfaces
更新于2025-10-24 16:33:39
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Power Efficiency Figure of Merit for Image Sensors
摘要: A new figure of merit (FoM) is developed with a theory, which enables the comparison of power efficiency of different image sensors based only on the pixel array size, frame rate, and total power consumption. The mathematical foundation of the FoM is provided, enabling the application of FoM to a generic image sensor supporting various read-out configurations. The model assumes a nonlinear relationship between the power consumption and operating frequency of building blocks, and the nonlinear factor is numerically derived based on the analytical modeling of image sensors. The FoM is applied to the studies from 1999 to 2018, which clarifies the trend of improvement as well as visualizes several breakthroughs in the development history.
关键词: modeling,CMOS image sensor (CIS),power efficiency,figure of merit (FoM),power consumption
更新于2025-09-23 15:23:52
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Single Flip-Chip Packaged Dielectric Resonator Antenna for CMOS Terahertz Antenna Array Gain Enhancement
摘要: A single dielectric resonator antenna (DRA) capable of enhancing the antenna gain of each element of a 2×2 THz antenna array realized in a 0.18-μm CMOS technology is proposed in this work. The DRA implemented in a low-cost integrated-passive-device (IPD) technology is flip-chip packaged onto the CMOS antenna array chip through low-loss gold bumps. By designing the DRA to work at the higher-order mode of TE3,δ,9, only single DRA instead of conventionally needing four DRAs is required to simultaneously improve the antenna gain of each element of the 2×2 antenna array. This not only simplifies the assembly process but it can also reduce the assembly cost. Moreover, the DRA can provide great antenna gain enhancement because of being made of high-resistivity silicon material and higher-order mode operation. The simulated antenna gain of each on-chip patch antenna of the 2×2 CMOS antenna array can be increased from 0.1 to 8.6 dBi at 339 GHz as the DRA is added. To characterize the proposed DRA, four identical power detectors (PDs) are designed and integrated with each element of the 2×2 THz antenna array, respectively. By measuring the voltage responsivity of each PD output, the characteristics of each antenna of the antenna array with the proposed DRA, including the gain enhancement level and radiation pattern, can be acquired. The measurement results follow well with the simulated ones, verifying the proposed DRA operation principle. The four PDs with the proposed DRA are also successfully employed to demonstrate a THz imaging system at 340 GHz. To the best of the authors’ knowledge, the proposed DRA is the one with the highest-order operation mode at THz frequencies reported thus far.
关键词: Silicon,Flip-chip packaging,Terahertz,CMOS,Terahertz imaging system,Antenna,Higher-order mode,Power detector,Dielectric resonator antenna
更新于2025-09-23 15:23:52
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Chip-Scale Molecular Clock
摘要: An ultra-stable time-keeping device is presented, which locks its output clock frequency to the rotational-mode transition of polar gaseous molecules. Based on a high-precision spectrometer in the sub-terahertz (THz) range, our new clocking scheme realizes not only fully electronic operation but also implementations using mainstream CMOS technology. Meanwhile, the small wavelength of probing wave and high absorption intensity of our adopted molecules (carbonyl sulfide, 16O12C32S) also enable miniaturization of the gas cell. All these result in an 'atomic-clock-grade' frequency reference with small size, power, and cost. This paper provides the architectural and chip-design details of the first proof-of-concept molecular clock using a 65-nm CMOS bulk technology. Using a 231.061-GHz phase-locked loop (PLL) with frequency-shift keying (FSK) modulation and a sub-THz FET detector with integrated lock-in function, the chip probes the accurate transition frequency of carbonyl sulfide (OCS) gas inside a single-mode waveguide, and accordingly adjusts the 80-MHz output of a crystal oscillator. The clock consumes only 66 mW of dc power and has a measured Allan deviation of 3.8 × 10^{-10} at an averaging time of τ = 1000 s.
关键词: CMOS,molecular clock,rotational spectroscopy,Allan deviation,GPS,carbonyl sulfide (OCS),frequency stability,navigation
更新于2025-09-23 15:23:52
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Advancement of CMOS Transimpedance Amplifier for Optical Receiver
摘要: Transimpedance amplifier (TIA) is an essential component of optical receivers, and this type of amplifier converts the photocurrent to a voltage signal. The overall performance of the optical receiver greatly depends on the performance of this component. Low-power, low-noise, and compact TIA has been realized in current development in CMOS technology. The high demands of an optical receiver has led to the optimization and development of the TIA designed specifications. However, the conventional CMOS TIA design is limited mainly because of its dependency on input node capacitance. In this article, the advancement of TIAs in data communication and instrumentation based on different design architectures and performances is discussed. This review will serve as a comparative study and reference for designing fully integrated CMOS TIA for future optical receivers.
关键词: TIA,Gain,CMOS,Sensor,Optical receiver
更新于2025-09-23 15:23:52
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Wavelet Denoising of High-Bandwidth Nanopore and Ion-Channel Signals
摘要: Recent work has pushed the noise-limited bandwidths of solid-state nanopore conductance recordings to more than 5 MHz and of ion channel conductance recordings to more than 500 kHz through the use of integrated complementary metal-oxide-semiconductor (CMOS) integrated circuits. Despite the spectral spread of the pulse-like signals that characterize these recordings when a sinusoidal basis is employed, Bessel filters are commonly used to denoise these signals to acceptable signal-to-noise ratios (SNRs) at the cost of losing many of the faster temporal features. Here, we report improvements to the SNR that can be achieved using wavelet denoising instead of Bessel filtering. When combined with state-of-the-art high-bandwidth CMOS recording instrumentation, we can reduce baseline noise levels by over a factor of four compared to a 2.5-MHz Bessel filter while retaining transient properties in the signal comparable to this filter bandwidth. Similarly, for ion channel recordings, we achieve a temporal response better than a 100-kHz Bessel filter with a noise level comparable to that achievable with a 25-kHz Bessel filter. Improvements in SNR can be used to achieve robust statistical analyses of these recordings, which may provide important insights into nanopore translocation dynamics and mechanisms of ion channel function.
关键词: ion channel,Nanopore,CMOS,wavelet,denoise.,SNR
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Performance Enhancement Of Cmos Terahertz Detector
摘要: For improving the performance of CMOS terahertz detectors, parasitic capacitance reduction technique and new working model are proposed for MOSFET devices. We investigate the influence of source parasitic capacitance and drain-to-source current on the performance of CMOS terahertz detectors and analyze the relationship to the voltage responsivity (RV) and noise equivalent power (NEP) of detectors. Experiment on the CMOS detectors with a 650GHz antenna shows the maximum improvement of voltage responsivity can attain to 155% by suppressing gate-source parasitic capacitance. The additional drain current Ids can further increase RV while NEP remains unchanged.
关键词: Antenna,CMOS THz detectors,DC current,Voltage response
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - Cleveland, OH, USA (2018.10.17-2018.10.19)] 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - A μRadio CMOS Device for Real-Time In-Tissue Monitoring of Human Organoids
摘要: Human-derived brain organoids were proposed for the generation of functional in vitro models and human brain tissues for drug-discovery, precision medicine and cell-based clinical therapies. However, their generation is currently subjected to a high variability which limits their routine exploitation. To achieve a quality-controlled production of brain organoids and to provide readout capabilities for assays development, we propose to realize active micro-scale devices that can be embedded into living 3D cell assemblies to provide in-tissue wireless sensing and monitoring of biosignals. Here, we evaluate a low-power solution that integrates into a 100μm×100μm area all circuits required for sensing and amplification of bioelectrical signals while providing RF wireless power delivery and data transmission. Circuit simulations on a 130nm RF-CMOS node demonstrate the feasibility of such solution with a 6.18μW of power consumption. Preliminary in vitro experiments with dummy Si micro-devices demonstrate their integration into 3D cell aggregates during cell culture.
关键词: CMOS,low-power,RF,Human brain organoids,wireless biosensing
更新于2025-09-23 15:23:52