Photonic Sensor Research Articles

Dual-band highly-sensitive SPR photonic crystal fiber sensor based on birefringence analysis

In this paper, a dual-band highly-sensitive D-shaped photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is proposed and numerically analyzed. Au-TiO2 grating is deposited on the flat surface of D-shaped PCF, thus surface plasmon resonances are excited to detect the change of refractive index (RI) of analyte. Rabi-like splitting spectrum is achieved by the introduction of a small air hole in the fiber. Besides spectrum analysis, it is found that the resonance wavelengths can be located by the abnormal change of birefringence. Moreover, complete coupling and incomplete coupling of the guided mode and plasmonic mode can be distinguished from our simulation results. The influences of structural parameters are also analyzed systematically. Simulation results show that the two loss peaks have different RI detection ranges, and the maximum sensitivity reaches 26700 nm/RIU. The proposed sensor could be applied widely in biomedical and chemical fields.

3D printed electronics with nanomaterials.

A large variety of printing, deposition and writing techniques have been incorporated to fabricate electronic devices in the last decades. This approach, printed electronics, has gained great interest in research and practical applications and is successfully fuelling the growth in materials science and technology. On the other hand, a new player is emerging, additive manufacturing, called 3D printing, introducing a new capability to create geometrically complex constructs with low cost and minimal material waste. Having such tremendous technology in our hands, it was just a matter of time to combine advances of printed electronics technology for the fabrication of unique 3D structural electronics. Nanomaterial patterning with additive manufacturing techniques can enable harnessing their nanoscale properties and the fabrication of active structures with unique electrical, mechanical, optical, thermal, magnetic and biological properties. In this paper, we will briefly review the properties of selected nanomaterials suitable for electronic applications and look closer at the current achievements in the synergistic integration of nanomaterials with additive manufacturing technologies to fabricate 3D printed structural electronics. The focus is fixed strictly on techniques allowing as much as possible fabrication of spatial 3D objects, or at least conformal ones on 3D printed substrates, while only selected techniques are adaptable for 3D printing of electronics. Advances in the fabrication of conductive paths and circuits, passive components, antennas, active and photonic components, energy devices, microelectromechanical systems and sensors are presented. Finally, perspectives for development with new nanomaterials, multimaterial and hybrid techniques, bioelectronics, integration with discrete components and 4D-printing are briefly discussed.

Photonic crystal fibre sensor for alcohol detection with extremely low birefringence

Photonic crystal fibre sensor for alcohol detection with extremely low birefringence

A doped-polymer based porous silicon photonic crystal sensor for the detection of gamma-ray radiation.

In this research, a theoretical investigation of the one-dimensional defective photonic crystals is considered for the detection of gamma-ray radiation. Each unit cell of the considered one-dimensional photonic crystals (1D PhCs) is composed of two layers designed from porous silicon infiltrated by poly-vinyl alcohol polymer doped with crystal violet (CV) and carbol fuchsine (CF) dyes (doped-polymer) with different porosity. In addition, a single layer of doped-polymer is included in the middle of the designed 1D PhCs to stimulate the localization of a distinct resonant wavelength through the photonic band gap. In particular, the appearance of this resonant mode represents the backbone of our study towards the detection of γ-ray radiation with doses from 0 to 70 Gy. The Bruggeman's effective medium equation, the fitted experimental data to the refractive index of the doped-polymer, and the Transfers Matrix Method (TMM) serve as the mainstay of our theoretical treatment. The numerical findings provide significant contributions to some of the governing parameters such as the thicknesses of the considered materials on the performance of the presented sensor, the effect of incidence angle and the porosity of the considered materials on the resonance wavelength. In this regard, at optimum values of these parameters the sensitivity, quality factor, signal-to-noise ratio, detection limit, sensor resolution, and figure of merit that are obtained are 205.7906 nm RIU-1, 9380.483, 49.315, 2.05 × 10-5 RIU, 3.27 × 10-5, and 2429.31 RIU-1, respectively. Therefore, we believe that the suggested design could be of significant interest in many industrial, medical, and scientific applications.

A photonic biosensor-integrated tissue chip platform for real-time sensing of lung epithelial inflammatory markers.

Tissue chip (TC) devices, also known as microphysiological systems (MPS) or organ chips (OCs or OoCs), seek to mimic human physiology on a small scale. They are intended to improve upon animal models in terms of reproducibility and human relevance, at a lower monetary and ethical cost. Virtually all TC systems are analyzed at an endpoint, leading to widespread recognition that new methods are needed to enable sensing of specific biomolecules in real time, as they are being produced by the cells. To address this need, we incorporated photonic biosensors for inflammatory cytokines into a model TC. Human bronchial epithelial cells seeded in a microfluidic device were stimulated with lipopolysaccharide, and the cytokines secreted in response sensed in real time. Sensing analyte transport through the TC in response to disruption of tissue barrier was also demonstrated. This work demonstrates the first application of photonic sensors to a human TC device, and will enable new applications in drug development and disease modeling.

DOPPLER OPTICAL PROBE FOR DROP SIZE, VELOCITY, AND FLUX MEASUREMENTS IN ASSISTED ATOMIZATION

For research as well as for process control, reliable drop size, velocity, and flux measurements are desirable in particular in dense, high-speed flows. A new optical probe has been recently manufactured by A2 Photonic Sensors company that combines an accurate phase detection capability (its latency length is small, about 6 µm) with the collection of a Doppler signal that provides the absolute velocity of an incoming gas-liquid interface. In this article, raw signals acquired over diverse flow conditions in terms of gas velocity and liquid concentration are analyzed. A dedicated signal processing routine is then proposed and optimized. The latter provides statistics on drop velocity and size. It also gives access to local liquid concentration and liquid flux. This Doppler probe combined with its processing has been tested in sprays produced from assisted atomization over a wide range of flow conditions. Transverse profiles of spray characteristics are presented for gas injection velocities ranging from 32 m/s to 283 m/s, for drops Sauter mean diameters D<sub>32</sub> varying from 37 µm to 275 µm, and for number densities-as estimated from liquid concentration and D<sub>32</sub>-comprised between 1 #/mm<sup>3</sup> and 218 #/mm<sup>3</sup>. The Doppler probe happens to be able to consistently detect chords as small as 4 µm, and to ensure a significant (up to 70%) fraction of direct velocity measurements. Besides, the injected liquid flow rate is recovered from the spatial integration of local liquid fluxes within 8% for gas velocities up to 50 m/s and within 17% for gas velocities above 90 m/s. Hence, the new Doppler probe combined with the proposed processing provides reliable statistics on drop velocity, size, and flux, and is a valuable tool for investigating dense, high-velocity, and fine sprays.

4-Field spontaneous symmetry breakings in photonic molecules

We present in this work a study of 4-field symmetry breakings in two photonic molecule structures consisting of two identical microresonators with distinct coupling arrangements. Mediated by the Kerr-interaction, the systems also display different 2-field symmetry breakings, periodic switching and chaos. The wide range of nonlinear optical dynamics makes the system ideal for all-optical switching, optical memories, telecommunication systems, polarization controllers and integrated photonic sensors.

Biofunctionalization of Multiplexed Silicon Photonic Biosensors.

Silicon photonic (SiP) sensors offer a promising platform for robust and low-cost decentralized diagnostics due to their high scalability, low limit of detection, and ability to integrate multiple sensors for multiplexed analyte detection. Their CMOS-compatible fabrication enables chip-scale miniaturization, high scalability, and low-cost mass production. Sensitive, specific detection with silicon photonic sensors is afforded through biofunctionalization of the sensor surface; consequently, this functionalization chemistry is inextricably linked to sensor performance. In this review, we first highlight the biofunctionalization needs for SiP biosensors, including sensitivity, specificity, cost, shelf-stability, and replicability and establish a set of performance criteria. We then benchmark biofunctionalization strategies for SiP biosensors against these criteria, organizing the review around three key aspects: bioreceptor selection, immobilization strategies, and patterning techniques. First, we evaluate bioreceptors, including antibodies, aptamers, nucleic acid probes, molecularly imprinted polymers, peptides, glycans, and lectins. We then compare adsorption, bioaffinity, and covalent chemistries for immobilizing bioreceptors on SiP surfaces. Finally, we compare biopatterning techniques for spatially controlling and multiplexing the biofunctionalization of SiP sensors, including microcontact printing, pin- and pipette-based spotting, microfluidic patterning in channels, inkjet printing, and microfluidic probes.

Double-Network Hydrogel-Based Photonic Crystal Sensor for Mechanical Force Naked Eye Sensing and Its Application in Medical Compressive or Stretchy Instruments.

Herein, we coalesced a poly(acrylamide-co-N-Acryloyl phenylalanine)/polyacrylamide double-network (P(AM-co-APA)/PAM DN) hydrogel with a photonic crystal array, fabricating a mechanochromic sensor for application in flexible medical instruments by naked eye monitoring. The intensified mechanical properties of the DN hydrogel were proved by the mechanical property tests, which are attributed to the interactions of chemical bonds and hydrogen bonds between the two polymer networks. In the range of stress from 0 to 328 kPa, the reflected light wavelength of this sensor changed from 659 to 480 nm and the color changed from red to blue in response; in the range of pressure from 0 to 85 kPa, the sensor exhibited a spectrum changing from 658 nm to 467 nm, covering almost the whole visible color range. The prepared sensor was incorporated into medical instruments including the femoral artery hemostat and bandage to indicate pressure and tensile stress in practical applications. Within the appropriate pressure for wound recovery, the sensitivity and correlation between the external stimulus of pressure and wavelength of this integrated sensor were 5.58 nm·kPa-1 and over 0.99, respectively. Ultimately, the sensor proved to be tough, sensitive, and durable, showing a broad prospect of a series of future applications.

Fully integrated optical sensor system with intensity interrogation

Introduction: Today sensor systems based on integrated photonics devices are the most important branch of embedded information and control systems for various functions. The output characteristics of a sensor system are significantly determined by the efficiency of the interrogator. The intensity interrogator based on a microring resonator can provide a high scanning rate and sensitivity that meets the requirements of a wide range of applications. Purpose: To develop an effective sensor system composed of a refractometric sensor and an interrogator located on the same photonic integrated circuit for marker-free determination of the concentration of substances in liquids. Methods: We use the numerical simulation of electromagnetic field propagation in a waveguide system (integrated silicon waveguides on a silicon dioxide substrate) in the research. The simulation has been carried out using the Ansys Lumerical environment, the FDTD (Finite Difference Time Domain) solver. The parameters of the microring resonators were optimized to obtain the coupling coefficients between the waveguides, providing the operation in the critical coupling mode. Results: We propose the concept of a fully integrated photonic sensor system based on micro-ring add-drop resonators. A sensor based on microring resonators has been developed, which consists of two half-rings with a radius of 18 μm, connected by sections of straight waveguides 3 μm long. An interrogator represented by a microring resonator with a radius of 10 µm has been developed. According to simulation results with a broadband source, the achieved sensor sensitivity was 110 nm per refractive index change, or 1350 dB per refractive index change. We propose a technique for choosing the optimal characteristics of the sensor and interrogator targeted to improve the complete system efficiency. Practical relevance: Sensor systems based on photonic integrated circuits can meet the demand for devices characterized by low power consumption, small size, immunity to electromagnetic interference and low cost.

A CMOS-compatible heterogeneous interferometer for chip-scale temperature sensing

We report a photonic temperature sensor with enhanced performance in both broad- and narrow-bandwidth optical measurements. The device consists of a heterogeneously integrated Mach–Zehnder interferometer with arms composed of silicon and silicon nitride waveguides whose thermo-optic coefficients differ by an order of magnitude. The waveguides are fabricated in distinct layers of a monolithic device and guide light in a single transverse-electric mode. The resulting small bend radii enable compact sensing of temperatures local to integrated photonic components with a device footprint of 580 × 410 μm2. Furthermore, the dual layers of the sensor enable overlaying of the spiral arms of the interferometer over each other or other photonic circuit components. We measure a sensitivity of 324 pm/K, an over threefold enhancement compared to the measurement of an asymmetric Mach–Zehnder constructed of silicon waveguides on the same device. We additionally define a useful figure of merit for the side-of-fringe measurement regime, which uses direct detection of a narrow linewidth laser and show that the reported device is also competitive on this metric.

Ultra-compact photonic crystal nanocavity-based sensor for simultaneous detection of refractive index and temperature

Ultra-compact photonic crystal nanocavity-based sensor for simultaneous detection of refractive index and temperature

Photonic crystal fiber refractive index sensor based on SPR

Photonic crystal fiber refractive index sensor based on SPR

Numerical analysis of the highly non-linear and ultra-sensitive modified core of a photonic crystal fiber sensor for detection of liquid analytes

A design of the highly non-linear and ultra-sensitive modified core of a photonic crystal fiber (PCF) sensor is reported for the detection of various liquid analytes. The sensor design comprises three rings of a hexagonal lattice around the liquid-infiltrated hollow core. A steric-shaped hollow core design in PCF effectively optimizes the sensor’s sensitivity and performance. The design is analyzed numerically by using the full vector finite element method with perfectly matched layers to find a rigorous solution. The proposed PCF sensor exhibits ultra-high relative sensitivity, a high power fraction, high non-linearity coefficient, low confinement loss, ultra-low chromatic dispersion, compact effective mode area, and single-mode operation in a wider wavelength range, i.e., within visible and infrared wavelength regimes. At an operating wavelength of 1.0 µm, optimum relative sensitivities of 96.37%, 97.40%, and 99.82% with high non-linear coefficients of 78.0 W − 1 k m − 1 , 66.09 W − 1 k m − 1 , and 62.57 W − 1 k m − 1 and extremely low confinement loss of ∼ 10 − 10 d B / m are obtained for water, ethanol, and benzene analytes, respectively. Further, waveguiding characteristics of the PCF sensor endorse its usage for a range of liquid analyte detections. It is a simple design and can be fabricated using existing manufacturing technologies.

Quad core gold coated photonic crystal fiber temperature sensor based on surface plasmon resonance

This paper shows a simple quad core Photonic Crystal Fiber (PCF) temperature sensor based on Surface Plasmon Resonance (SPR) which has very high sensitivity and sensor resolution. For evaluating the sensing performance Finite Element Method (FEM) is used. In this design, gold is used as plasmonic material and the outer layer of the designed PCF has to be filled by it for making the fabrication easier than any other model. Besides, the Chloroform is used as the temperature sensitive liquid (analyte). The designed temperature sensor has the maximum wavelength sensitivities which are 7.5 nm/°C and 10.5 nm/°C for x and y-polarization respectively. The sensor shows the resolution of 13.33 × 10−3 RIU for x-polarization and 9.52 × 10−3 RIU for y-polarization. Core diameter, radius of air hole, thickness of gold and pitch are the structural parameters which are adjusted to their optimized value for getting higher sensitivity. Easy fabrication and simplicity are the major aspects of this proposed model which makes it applicable to various applications such as medical science, power plant, engineering sector, environment monitoring etc.

Improvement of Visible Photodetection of Chemical Vapor Deposition-Grown MoS2 Devices via Graphene/Au Contacts.

Two-dimensional (2D) molybdenum disulfide (MoS2) is a promising material for constructing high-performance visible photosensor arrays because of its high mobility and scale-up process. These distinct properties enable the construction of practical optoelectrical sensor arrays. However, contact engineering for MoS2 films is not still optimized. In this work, we inserted a graphene interlayer between the MoS2 films and Au contacts (graphene/Au) via the wet-transfer method to boost the device performance. Using graphene/Au contacts, outstanding electrical properties, namely field-effect mobility of 12.06 cm2/V∙s, on/off current ratio of 1.0 × 107, and responsivity of 610 A/W under illumination at 640 nm, were achieved. These favorable results were from the Fermi-level depinning effect induced by the graphene interlayer. Our results may help to construct large-area photonic sensor arrays based on 2D materials.

Photonic Crystal Fiber Sensor for Detecting Sulfuric Acid in Different Concentrations

A high-performance photonic crystal fiber sensor for sulfuric acid detection is designed and investigated, undertaken through a full vector Finite Element Method on COMSOL Multiphysics software to establish the optical properties of effective refractive index, power fraction, relative sensitivity, confinement loss, chromatic dispersion, and propagation constant. Different aqueous sulfuric acid concentrations of 0%, 10%, 20%, 30%, and 40% were selected as the test analytes. The dimensions of two cladding rings of the hexagon- and circular-shaped air holes and a circular core hole denoted outstanding outcomes of relative sensitivity and confinement loss. At 1.1 µm optimum wavelength, 0%, 10%, 20%, 30%, and 40% sulfuric acid concentrations depict relative sensitivities of 97.08%, 97.67%, 98.06%, 98.39%, and 98.67%, respectively, and confinement losses of 1.32 × 10−12 dB/m, 4.11 × 10−12 dB/m, 1.46 × 10−12 dB/m, 6.34 × 10−12 dB/m, and 2.12 × 10−12 dB/m, respectively.

Magnetic and Electric Field Dependent Charge Transfer in Perovskite/Graphene Field Effect Transistors

AbstractStable all‐inorganic CsPbX3 perovskite nanocrystals (PNCs) with high optical yield can be used in combination with graphene as photon sensors with high responsivity (up to 106 A W−1) in the VIS‐UV range. The performance of these perovskite/graphene field effect transistors (FET) is mediated by charge transfer processes at the perovskite – graphene interface. Here, the effects of high electric (up to 3000 kV cm−1) and magnetic (up to 60 T) fields applied perpendicular to the graphene plane on the charge transfer are reported. The authors demonstrate electric‐ and magnetic‐field dependent charge transfer and a slow (>100 s) charge dynamics. Magneto‐transport experiments in constant (≈0.005 T s−1) and pulsed (≈1000 T s−1) magnetic fields reveal pronounced hysteresis effects in the transfer characteristics of the FET. A magnetic time is used to explain and model differences in device behavior under fast (pulsed) and slowly (continuous) changing magnetic fields. The understanding of the dynamics of the charge transfer in perovskite/graphene heterostructures developed here is relevant for exploitation of these hybrid systems in electronics and optoelectronics, including ultrasensitive photon detectors and FETs for metrology.

MEMS enabled suspended silicon waveguide platform for long-wave infrared modulation applications

Long-wave infrared (LWIR, 6–14 µm) is an important wavelength range as it covers abundant vibrational molecular fingerprints that can be used for gas/liquid sensing and absorption spectroscopy. Silicon waveguide-based passive photonic devices that offer advantages toward chip-scale miniaturization of photonic integrated circuits (PIC) and photonic sensors in LWIR have been explored. However, the modulation of Si-based guided-wave propagation in LWIR remains less reported. Here, we demonstrate a MEMS tunable directional coupler operating at a long-wave infrared wavelength range (6.4–7 µm) using suspended Si waveguides with subwavelength gratings. Leveraging the membrane transfer technology, the whole photonic waveguide device membrane is transferred onto a receiver substrate with a cavity that allows sufficient displacement for MEMS electrostatic actuation. The proposed device experimentally achieved an optical attenuation of −14.25 dB with 90 V DC bias voltage, while having a response time of 177 µs. In addition, the demonstration of using such a device for computational spectroscopy has been validated.

HE1,1 mode excited surface plasmon resonance for high-sensitivity sensing by photonic crystal fibers.

Surface plasmon resonance (SPR) is widely used in photonic crystal fiber sensors. In this work, a photonic crystal fiber sensor based on HE1,1 mode excited SPR is designed and analyzed by the finite element method. The maximum wavelength sensitivity, optimal resolution, and amplitude sensitivity of the optical fiber sensor are 24,600 nm/RIU, 4.07×10-6RIU, and 1164.13RIU-1, respectively, for the refractive index range between 1.29 and 1.39. The sensor has excellent properties and wide application prospects in bimolecular and biochemical sensing, environmental monitoring, food safety, and other fields.