Photonic Detection Research Articles

Pollen detection through integrated microfluidics and smartphone-driven deep learning systems

The presence of atmospheric particulates, including bioaerosols such as pollen, significantly impacts air quality and poses potential health risks. Therefore, accurate detection and categorization of these particulates are crucial for evaluating their health implications. This study introduces an innovative, automated system for analyzing atmospheric particulates, combining microfluidic technology with a smartphone-based photonic detection platform. The system integrates a miniaturized optical microscopy module and a consumer-grade high-frame-rate camera, creating an affordable, accessible solution priced at only 50 USD. Such cost-effectiveness promotes the widespread adoption of the technology and facilitates community-driven environmental monitoring. The study developed a compact, rapid, real-time, and continuous air micro-particle sampling and detection platform. The integration of an automatic collection device with a microfluidic detection chip enables continuous sampling and detection. A lightweight object detection network, designated as “PollenDet,” was trained, achieving a mean average precision (mAP) of 94.6%. This technology provides essential insights into the dynamics of airborne particulates, thereby enhancing our understanding of their overall impact.

A Photonic Immunosensor Detection Method for Viable and Non-Viable E. coli in Water Samples.

Detection and enumeration of coliform bacteria using traditional methods and current molecular techniques against E. coli usually involve long processes with less sensitivity and specificity to distinguish between viable and non-viable bacteria for microbiological water analysis. This approach involves developing and validating an immunosensor comprising ring resonators functionalized with specific antibodies surrounded by a network of microchannels as an alternative method for detecting and indirectly enumerating Escherichia coli in samples of water for consumption. Different ELISA assays were conducted to characterize monoclonal and polyclonal antibodies selected as detection probes for specific B-galactosidase enzymes and membrane LPS antigens of E. coli. An immobilization control study was performed on silicon nitride surfaces used in the immunosensor, immobilized with the selected antibodies from the ELISA assays. The specificity of this method was confirmed by detecting as few as 10 CFU/mL of E. coli from viable and non-viable target bacteria after applying various disinfection methods to water samples intended for human consumption. The 100% detection rate and a 100 CFU/mL Limit of Quantification of the proposed method were validated through a comprehensive assessment of the immunosensor-coupled microfluidic system, involving at least 50 replicates with a concentration range of 10 to 106 CFU/mL of the target bacteria and 50 real samples contaminated with and without disinfection treatment. The correlation coefficient of around one calculated for each calibration curve obtained from the results demonstrated sensitive and rapid detection capabilities suitable for application in water resources intended for human consumption within the food industry. The biosensor was shown to provide results in less than 4 h, allowing for rapid identification of microbial contamination crucial for ensuring water monitoring related to food safety or environmental diagnosis and allowing for timely interventions to mitigate contamination risks. Indeed, the achieved setup facilitates the in situ execution of laboratory processes, allowing for the detection of both viable and non-viable bacteria, and it implies future developments of simultaneous detection of pathogens in the same contaminated sample.

Specific and Simultaneous Detection of E. coli O157:H7 and Shiga-like Toxins Using a Label-Free Photonic Immunosensor

The current study outlines the advancement of an innovative technique for the simultaneous detection of E. coli O157:H7 and its Shiga-like toxins in food samples by utilizing a photonic label-free biosensor coupled with a microfluidic system. This detection method relies on ring resonator transduction that is functionalized with specific bioreceptors against O157:H7 on silicon nitride surfaces capable of binding specifically to the antigen bacterium and its verotoxins. This experiment included the characterization of selected monoclonal and polyclonal antibodies employed as detection probes through ELISA immunoassays exposed to target bacterial antigens. A thorough validation of photonic immunosensor detection was conducted on inoculated minced beef samples using reference standards for E. coli O157:H7 and its verotoxins (VTx1 and VTx2) and compared to gold-standard quantification. The lowest limit-of-detection values of 10 CFU/mL and 1 ppm were achieved for the detection of bacteria and its verotoxins. In this study, the lowest limit of quantification (LoQ) achieved for bacterial quantification was 100 CFU/mL, and, for verotoxins, it was 2 ppm. This study confirmed the effectiveness of a new quality control and food hygiene method, demonstrating the rapid and sensitive detection of E. coli O157:H7 and its verotoxins. This innovative approach has the potential to be applied in food production environments.

Verifiable Blind Quantum Computing with Trapped Ions and Single Photons.

We report the first hybrid matter-photon implementation of verifiable blind quantum computing. We use a trapped-ion quantum server and a client-side photonic detection system networked via a fiber-optic quantum link. The availability of memory qubits and deterministic entangling gates enables interactive protocols without postselection-key requirements for any scalable blind server, which previous realizations could not provide. We quantify the privacy at ≲0.03 leaked classical bits per qubit. This experiment demonstrates a path to fully verified quantum computing in the cloud.

On-Chip Photonic Detection Techniques for Non-Invasive In Situ Characterizations at the Microfluidic Scale.

Microfluidics has emerged as a robust technology for diverse applications, ranging from bio-medical diagnostics to chemical analysis. Among the different characterization techniques that can be used to analyze samples at the microfluidic scale, the coupling of photonic detection techniques and on-chip configurations is particularly advantageous due to its non-invasive nature, which permits sensitive, real-time, high throughput, and rapid analyses, taking advantage of the microfluidic special environments and reduced sample volumes. Putting a special emphasis on integrated detection schemes, this review article explores the most relevant advances in the on-chip implementation of UV-vis, near-infrared, terahertz, and X-ray-based techniques for different characterizations, ranging from punctual spectroscopic or scattering-based measurements to different types of mapping/imaging. The principles of the techniques and their interest are discussed through their application to different systems.

Modified SiP single-polarization CADD receiver.

In cost-sensitive application scenarios, increasing the data rate per channel under a limited receiver bandwidth is critical, and thus, the transceivers with low costs and high electrical spectral efficiencies (ESEs) are highly desirable. In this Letter, we demonstrate a modified silicon photonic (SiP) carrier-assisted differential detection (CADD) receiver with a record ESE for single polarization. The ESE of the conventional CADD is mainly limited by the transfer function that originated from the optical delay and hybrid. We modify the transfer function of the CADD by placing an additional delay in parallel to the original delay path. Consequently, the modified transfer function exhibits a sharper slope around the zero frequency, leading to a higher ESE. Here we employ complementary metal-oxide-semiconductor-compatible SiP integration to further reduce the cost and footprint of the modified CADD receiver. In the experiment, 280-Gb/s raw rate (net 226-Gb/s) 16-QAM OFDM signal after 80-km SMF transmission was detected using a 36.5-GHz SiP modified CADD receiver, with a bit error ratio below the 24% SD-FEC threshold. To our best knowledge, we achieve a record net 6.2-b/s/Hz ESE for an integrated single-polarization DD receiver with a 16-QAM format.

Visual Recognition of Volatile Organic Compounds by Photonic Nose Integrated with Multiple Metal-Organic Frameworks.

The photonic nose inspired by the olfactory system is an integrated detection platform constructed by multiple sensing units as channels. However, in the detection of volatile organic compounds (VOCs), the sensing results that cannot be directly readable and the poor ability to distinguish analytes with similar chemical properties are the main challenges faced by this sensor. Here, 8 metal-organic frameworks (MOF)-based photonic crystals are used as the basic sensing units to construct a photonic nose detection platform. The microscopic adsorption of VOCs by MOFs enables the photonic crystals (PCs) to produce macroscopic structural color output, and further makes the photonic nose have specific color fingerprints for different VOCs, the response time of all PCs to VOCs can be within 1s. Through the color fingerprint, the visual identification of VOCs produced by 5 common solvent vapors is realized, and 9 VOCs with similar chemical properties are further distinguished. In addition, the application potential of the photonic nose in the actual environment is verified by identifying different contents of benzene in the paint. It is envisaged that the MOF-based photonic nose has great reference value for the development of intelligent and multi-component synergistic functional gas sensors.

Optofluidic photonic crystal micro sensor for enhanced detection of infectious diseases

This research encompasses a comprehensive study on the application of 1D photonic crystal-based detection in the context of infectious diseases, specifically targeting malaria stages, chikungunya, and dengue. It explores the interactions between the photonic crystal and various biomolecules associated with these diseases, with a focus on platelets, plasma, and uric acid. The transmission spectrum graphs obtained from these interactions provide crucial insights into the detection and quantification of the diseases, offering real-time and label-free monitoring capabilities. Maximum sensitivity of 550 nm RIU−1 and Q factor of 29,260 obtained. Additionally, the study incorporates the design and analysis of a microfluidic channel optimized for the proposed sensor, ensuring accurate temperature and pressure distributions. The results demonstrate the feasibility of the microfluidic platform for enhancing sensor performance and fluid handling. This integrated approach shows promising potential for early disease diagnosis and monitoring, paving the way for practical implementation and further advancements in the field of sensing and diagnostics

A joint algorithm based on photon heterodyne detection

The photonic heterodyne detection system, which has both the anti-interference advantage of the heterodyne detection and the detection sensitivity at the photon level, is widely used in the detection of long-range non-cooperative targets. In this paper, a joint algorithm is proposed to improve the signal-to-noise ratio (SNR) of the system for the problem of low SNR in remote target detection. Firstly, the photon arrival sequences with initial phases in the range of (-π/4, π/4) are coherently accumulated, and then the autocorrelation algorithm is used to obtain the final power spectral density (PSD). After being processed by the joint algorithm, the differential frequency amplitude of the experimental signal is finally improved by a factor of 3.14 and the SNR is improved by a factor of 2.72.

Tuberculosis biomedical sensor based on on-chip nanocavity 2D photonic crystal with high sensitivity and quality factor

Tuberculosis (TB) stands as one of the most severe and fatal communicable diseases in the universe, in accordance with the World Health Organization (WHO). Before the COVID-19 pandemic, tuberculosis held the highest mortality rate due to an individual infection, surpassing even HIV/AIDS. The identification of the disease at its initial stages plays a crucial role in patient management and has the potential to enhance the chances of survival. This study presents a unique biomedical sensor based on a two-dimensional (2D) photonic crystal, which demonstrates high accuracy in diagnosing and distinguishing between regular and irregular strains of tuberculosis bacteria. The proposed sensor is designed, presented, and evaluated. It can identify different types of tuberculosis with ultra-high-quality factor and adequate sensitivity in comparison with related photonic detection methods. Also, the presented sensor features a simplistic design with a fabrication possibility using current technologies. The presented sensor exhibited an ultra-quality factor of 10731, an extremely small detection limit of 5.87 × 10-6, and a remarkable sensitivity of 1738.7 nm/RIU. A comprehensive overview of non-optical sensing methods is addressed and linked to the current work. A detailed comparative exploration of this study and associated photonic-based literatures are carried out to verify the efficiency and originality of the proposed sensor.

Carrier conversion from terahertz wave to dual-wavelength near-infrared light for photonic terahertz detection in wireless communication.

THz waves are promising wireless carriers for next-generation wireless communications, where a seamless connection from wireless to optical communication is required. In this study, we demonstrate carrier conversion from THz waves to dual-wavelength NIR light injection-locking to an optical frequency comb using asynchronous nonpolarimetric electro-optic downconversion with an electro-optic polymer modulator. THz wave in the W band was detected as a stable photonic RF beat signal of 1 GHz with a signal-to-noise ratio of 20 dB via the proposed THz-to-NIR carrier conversion. In addition, the results imply the potential of the photonic detection of THz waves for wireless-to-optical seamless communication.

Quantum heat diode versus light emission in circuit quantum electrodynamical system.

Precisely controlling heat transfer in a quantum mechanical system is particularly significant for designing quantum thermodynamical devices. With the technology of experiment advances, circuit quantum electrodynamics (circuit QED) has become a promising system due to controllable light-matter interactions as well as flexible coupling strengths. In this paper, we design a thermal diode in terms of the two-photon Rabi model of the circuit QED system. We find that the thermal diode can not only be realized in the resonant coupling but also achieve better performance, especially for the detuned qubit-photon ultrastrong coupling. We also study the photonic detection rates and their nonreciprocity, which indicate similar behaviors with the nonreciprocal heat transport. This provides the potential to understand thermal diode behavior from the quantum optical perspective and could shed new insight into the relevant research on thermodynamical devices.

A mid-infrared focusing grating coupler with a single circular arc element based on germanium on silicon.

A mid-infrared (MIR) focusing grating coupler (FGC) with a single circular arc element (CAE) in the front of the gratings based on a germanium-on-silicon (Ge-on-Si) platform is designed and demonstrated. It can be used equivalently to a traditional FGC with all-focusing gratings. By optimizing the structural parameters of the CAE, the combination of a tapered linear grating and the CAE can improve the coupling efficiency to 8.61%, which is twice as large as that of the traditional MIR grating couplers. To the best of our knowledge, it is the highest coupling efficiency in a full-etch grating coupler based on Ge-on-Si. Moreover, the proposed grating coupler can be used for refractive index (RI) sensing, and the maximum sensitivity is 980.7 nm/RIU when the RI changes from 1 to 1.04. By comparing with traditional grating couplers requiring secondary etching, the proposed full-etch grating coupler structure can reduce the complexity of fabrication and can provide a prospective platform for MIR photonic integration and photonic biosensor detection.

A 3-5 μm broadband YBCO high-temperature superconducting photonic crystal

Photonic crystal structures have excellent optical properties, so they are widely studied in conventional optical materials. Recent research shows that high-temperature superconducting periodic structures have natural photonic crystal features and they are favourable candidates for single-photon detection. Considering that superconductors have completely different properties from conventional optical materials, we study the energy level diagram and mid-infrared 3 μm–5 μm transmission spectrum of two-dimensional superconducting photonic crystals in both superconducting and quenched states with the finite element method. The energy level diagram of the circular crystal column superconducting structure shows that the structure has a large band gap width in both states. At the same fill factor, the circular crystal column superconducting structure has a larger band gap width than the others structures. For lattice structures, the zero transmission point of the square lattice structure is robust to the incident angle and environmental temperature. Our research has guiding significance for the design of new material photonic crystals, photon modulation and detection.

Dissipative solitons in optical microresonators

<p indent="0mm">A soliton is a stationary local structure that keeps its waveform and spreading speed during propagation. Recent research shows that chip-scale optical microresonators can support dissipative solitons with surprisingly high energy efficiency and stability. The formation of optical microresonator dissipative solitons requires two balances, gain-loss balance and dispersion-nonlinearity balance. The gain-loss balance maintains the soliton’s amplitude while the dispersion-nonlinearity balance keeps its width. In this paper, we review the formation, development, and applications of dissipative optical solitons, as well as dissipative mechanical solitons in optical microresonators, and analyze the balances in different solitons. This review mainly consists of two parts: Optical microresonator dissipative solitons and opto-mechanical microresonator dissipative solitons. The first part discusses a typical kind of solitons named dissipative Kerr solitons. Dissipative Kerr solitons balance the propagation dispersion through Kerr nonlinearity in optical microresonators and are widely studied due to their easy implementation in silicon-based microcavities. In order to improve the practical performance of dissipative Kerr solitons, researchers have proposed many schemes to improve their stability and efficiency. Meanwhile, various high-precision sensing applications based on dissipative Kerr solitons, such as photonic radar, range measurement, and absorption spectrum detection, have drawn extensive attention. The second part introduces the dissipative solitons in optomechanical microresonators. A recently-discovered type of solitons, optomechanical dissipative solitons, is introduced. Unlike the dissipative Kerr solitons, the optomechanical dissipative solitons gain their power from phonon lasing, and compensate the propagation dispersion by optomechanical nonlinearity. The dynamics of the optomechanical dissipative solitons are described by the modified Korteweg-de Vries equation. Low-frequency optomechanical dissipative solitons can achieve kHz-accuracy acoustic signal measurement, which can be used in acoustic detection and communication. Finally, we summarize the formation, development, and applications of dissipative solitons in optomechanical microresonators. We also provide an outlook for future applications like radio-frequency calibration, radio-frequency communications, and underwater tomography.

Characterization of colonization kinetics and virulence potential of Salmonella Enteritidis in chickens by photonic detection

The light emitting module lux operon (luxCDABE) of Photorhabdus luminescens can be integrated into a “dark” bacterium for expression under a suitable promoter. The technique has been used to monitor kinetics of infection, e.g., by studying gene expression in Salmonella using mouse models in vivo and ex vivo. Here, we applied the bioluminescence imaging (BLI) technique to track Salmonella Enteritidis (SEn) strains carrying the lux operon expressed under a constitutive promoter sequence (sigma 70) in chicken after oral challenge. Detectable photon signals were localized in the crop, small intestine, cecum, and yolk sac in orally gavaged birds. The level of colonization was determined by quantification of signal intensity and SEn prevalence in the cecum and yolk sac. Furthermore, an isogenic SEn mutant strain tagged with the lux operon allowed for us to assess virulence determinants regarding their role in colonization of the cecum and yolk sac. Interestingly, mutations of SPI-1(Salmonella Pathogenicity Island 1) and fur (ferric uptake regulator) showed significantly decreased colonization in yolk sac that was correlated with the BLI data. A similar trend was detected in a ΔtonB strain by analyzing enrichment culture data. The inherently low quantum yield, light scattering, and absorption by tissues did not facilitate detection of signals from live birds. However, the detection limit of lux operon has the potential to be improved by resonance energy transfer to a secondary molecule. As a proof-of-concept, we were able to show that sensitization of a fluorescent-bound molecule known as the lumazine protein (LumP) improved the limit of detection to a certain extent.

Transcutaneous Flexible Sensor for In Vivo Photonic Detection of pH and Lactate.

Clinical research shows that frequent measurements of both pH and lactate can help guide therapy and improve patient outcome. However, current methods of sampling blood pH and lactate make it impractical to take readings frequently (due to the heightened risk of blood infection and anemia). As a solution, we have engineered a subcutaneous pH and lactate sensor (PALS) that can provide continuous, physiologically relevant measurements. To measure pH, a sheet containing a pH-sensitive fluorescent dye is placed over 400 and 465 nm light-emitting diodes (LEDs) and a filter-coated photodetector. The filter-coated photodetector collects an emitted signal from the dye for each LED excitation, and the ratio of the emitted signals is used to monitor pH. To measure lactate, two sensing sheets comprising an oxygen-sensitive phosphorescent dye are each mounted to a 625 nm LED. One sheet additionally comprises the enzyme lactate oxidase. The LEDs are sequentially modulated to excite the sensing sheets, and their phase shift at the LED drive frequency is used to monitor lactate. In vitro results indicate that PALS successfully records pH changes from 6.92 to 7.70, allowing for discrimination between acidosis and alkalosis, and can track lactate levels up to 9 mM. Both sensing strategies exhibit fast rise times (< 5 min) and stable measurements. Multianalyte in vitro models of physiological disorders show that the sensor measurements consistently quantify the expected pathophysiological trends without cross talk; in vivo rabbit testing further indicates usefulness in the clinical setting.

Gelatinase-responsive photonic crystal membrane for pathogenic bacteria detection and application in vitro health diagnosis

Selective identification and rapid detection for multiple pathogenic bacteria are important to prevent bacterial infection. Herein, gelatinase-responsive photonic crystal membrane (PCM) is reported as rapid, selective and direct detection platform for multiple pathogenic bacteria. PCMs exhibit angle-independent structural color, and reflection spectra has negligible change after irradiation and storage under different temperature. The ultra-thin response layer makes shorter detection time (30 min) than the reported gelatin-based photonic crystal detection platform (10–12 h). There is obvious positive correlation between reflection spectra change and gelatinase concentration, even if the gelatinase was as low as 4.8 pM. PCM has high stability against multiple interferers, which are beneficial to improve the detection accuracy and reliability. PCM also show “selective” ability to identify typical pathogens from atypical pathogens through specific response to gelatinase, and good selectivity gives PCM direct detection ability without pretreatment. PCM could detect the pathogens bacteria concentration range spanning 7 orders of magnitude from 10 to 107 CFU/mL, and the relative error between gold standard method and the new platform is less than 10%. Furthermore, PCM's in vitro health diagnosis ability was proved by detecting pathogenic bacteria in artificial wound fluid and urine. All the results show that PCM is well promising platform for selective identifying and rapid detecting pathogenic bacteria in vitro diagnosis.

Remote photonic detection of human senses using secondary speckle patterns

Neural activity research has recently gained significant attention due to its association with sensory information and behavior control. However, the current methods of brain activity sensing require expensive equipment and physical contact with the tested subject. We propose a novel photonic-based method for remote detection of human senses. Physiological processes associated with hemodynamic activity due to activation of the cerebral cortex affected by different senses have been detected by remote monitoring of nano‐vibrations generated by the transient blood flow to the specific regions of the human brain. We have found that a combination of defocused, self‐interference random speckle patterns with a spatiotemporal analysis, using Deep Neural Network, allows associating between the activated sense and the seemingly random speckle patterns.

Quantum Chemical Computations of an Efficient Push-Pull NLO Chromophore 3-[4-Nitrophenyl Azo]- 9H- Carbazole-9-Ethanol

Electric-optic (EO) materials are being explored for applications ranging from fiber and satellite telecommunications, optical gyroscopes, to photonic detection of radar etc. Dipolar push-pull Organic chromophores that exhibit extended π-conjugation, in particular, show enhanced second order NLO properties. The present investigation reports the quantum chemical computations of the high efficiency push-pull NLO molecule 3-[(4-Nitrophenyl Azo)] - 9H-Carbazole-9-Ethanol (NPACE). The organic push-pull molecule is optimized in gaseous and in various solvent condition using Exchange correlation function (B3LYP/MP2). Molecular electrostatic potential, thermal properties and NBO analysis have also been performed in detail. The effective electron cloud moment in the molecule is mainly governed by the physical process termed intramolecular Charge Transfer (ICT).