Protein-protein interactions can be measured in live cells, at nanometer scale, using Fluorescence Lifetime Imaging Microscopy (FLIM) enabled Forster Resonance Energy Transfer (FRET). There are growing interests in exploring protein-protein interactions in drug discovery applications. Traditional single point confocal microscopes, however, are slow and unsuited to small molecule screening, especially

In this study we fabricated highly oxidized graphene oxides (GO) to reduce the optical bulk absorption, and to achieve a low-loss GO/silicon hybrid optical waveguide. The highly oxidized GO was fabricated using triple amount of oxidants and elongated oxidizing time via a modified Hummers’ method, together with post ozone treatment to effectively break down the C = C pi-conjugation network. The high

Metasurfaces have developed rapidly with the extraordinary electromagnetic properties in electromagnetic wave control in recent years. However, the conventional metasurfaces design based on the Method of Moments (MOM), Finite Element Method (FEM) and Finite Integration Technique (FIT) are still time-consuming and demand significant computation. In this paper, we proposed a polynomial regression of

This paper reviews materials and structural approaches that have been developed to reduce the excess noise in avalanche photodiodes and increase the gain-bandwidth product.

The well-known RF penetration method is implemented on the quantum cryptosystems. In this study, RF radiations from the single photon detectors in a quantum key distribution system are intercepted. It was found that the data contents of a quantum transmission system can be detected from the vicinity of the receiving parties by exploiting the radiations of avalanche effect of single photon detectors

Miniaturized spectrometers are being developed in the recent few years leveraging the rapidly-progressing technology and triggering new markets in the field of on-site and mobile spectroscopic analysis. Although some devices were commercialized for the near-infrared spectroscopy (NIRS), their size and cost still don't meet the requirements for the ubiquitous deployment of the spectrometer as a spectral

We propose and experimentally demonstrate the broadband power coupling and mode-order conversion based on the trapezoidal subwavelength grating (SWG) structures. The slowly varying trapezoidal SWGs alter the modal field distribution in two closely spaced waveguides and result in an enhanced and adiabatically changing coupling strength between them. As a result, high coupling efficiencies over broad

Current trends in microelectronics chip bonding and assembly encompass ultra-fine pitch components with flexible form factors and advanced die-attach materials, which can sustain conformal strain without compromise in adhesion and reliability. These trends have highlighted the need for advanced microfrabrication technologies, which allow the on-demand digital fabrication of interconnections and die-attach

Fibrosis is a prevalent problem that pathologically accompanies chronic inflammatory diseases. Despite the availability of various fibrosis treatments, therapeutic efficacy must be further improved to achieve better clinical outcomes. The purpose of this study is to develop a novel treatment by combining phloroglucinol (PHL) with photobiomodulation (PBM) to prevent skin fibrosis. In in vitro, 635 nm

Fourier Ptychography probes the sample from different directions to achieve label-free quantitative phase imaging with a large space-bandwidth product. However, special attention has to be paid in the calibration of the optical setup to assure the accurate knowledge of the geometrical parameters involved in the image reconstruction. Any slight misalignment can provoke incorrect synthesis of the observables

A light-adjustable illumination scheme for hand-held probe for photoacoustic tomography is presented in this paper. The overall size of the probe is 120 × 60 × 40 mm3, which is easy to be held. Compared with traditional photoacoustic probe design, it has the following advantages: (1) Different excitation modes, that is, the different relative position between laser illumination area and ultrasonic

The imagiology using Narrow Band Light (NBL) is widely employed in detection of mucosa's premature changes of gastrointestinal tract, while taking advantage of light spectral features by enhancing the vascular structures without the application of any type of dye. NBL uses two specific spectral bands centered in blue (415 nm) and green (540 nm). Despite their greater advantages, this technique is not

Lensless microscopy is a well known imaging technique, commonly referred as digital in-line holographic microscopy. In the established holography methods, both the spatial and temporal coherence of light play a crucial role in determining the resolution of reconstructed object. This strongly restricts this imaging method to use light sources of high spatio-temporal coherence. We report lensless microscopy

Intraplaque hemorrhage (IPH), which is a trigger and conveys all blood components into the plaque, influencing the cholesterol crystal formation and retention, haemoglobin and oxidative enzymes, and blood-borne proteolytic activity. IPH is one of the key determinants for plaque vulnerability. In this paper, we proposed a dual-modality endoscope probe with a diameter of 1 mm for simultaneously detecting

Ocular axial length (AL) is an important property of eyes used for determining their health prior to surgery. Estimation of AL is also crucial while making artificial lenses to replace impaired natural lenses. However, accurate measurement of AL requires a costly and bulky benchtop optical system. The complex structural features of eyes can be captured by fundus images, which can be easily captured

Here, we overview an optical coherence tomography image-guided needle puncture based on recent results, which can help operators more accurately indicate the depth position of the puncture needle into the body, reduce subjective judgment errors, and assist the physician in operating a smoother procedure, and increase the success rate of the operation. Artificial intelligence aided image interpretation

Blood vessel burst pressures were simulated and predicted for sealing and cutting of vessels in a two-step process, using low (<25 W), medium (∼100 W), and high (200 W) power lasers at a wavelength of 1470 nm. Monte Carlo optical transport, heat transfer, Arrhenius integral tissue damage simulations, and vessel pressure equations were utilized. The purpose of these studies was to first validate the

Most cancer deaths are associated with metastases resulting from the spread of circulating tumor cells (CTCs) from the primary tumor to vital organs. The existing methods for detection of CTCs as markers of metastasis progression are time consuming with several steps of sample processing, including red blood cell removal, labeling, immunomagnetic capture and isolation, which can lead to loss of CTCs

Infectious disease outbreaks such as Ebola and other Viral Hemorrhagic Fevers (VHF) require low-complexity, specific, and differentiated diagnostics as illustrated by the recent outbreak in the Democratic Republic of Congo. Here, we describe amplification-free spectrally multiplex detection of four different VHF total RNA samples using multi-spot excitation on a multimode interference waveguide platform

Dental diseases significantly impact the quality of life and human populations; the current X-ray diagnostic dental imaging method may also bring the potential health risks to humans. This study used human extracted teeth and rats as animal model to test a new near-infrared (NIR) dental fluorescence imaging system with a painless mouthwash for administering indocyanine green (ICG). Our results show

Heart-rate monitoring with an ethyl alpha-cyanoacrylate (EtCNA) based fiber Fabry-Perot (F-P) sensor is presented. The fiber F-P sensor is fixed in a capillary tube by using the EtCNA binder. Due to the lower Young's modulus of the EtCNA, the sensor can detect low frequency vibration with a high sensitivity. The fiber sensor is attached in a specially designed bracket to obtain the stable data. When

In this paper, we describe the combination of ultraviolet (UV) spectroscopy with the optical clearing technique to induce new tissue windows, evaluate their efficiency, study the diffusion properties of agents and discriminate cancer. The use of highly concentrated glycerol solutions has induced high efficiency clearing effects in the UV, both in human colorectal and gingival tissues. The protein dissociation

We present a hardware-friendly deep learning architecture with one-dimensional convolutional neural networks (1D CNN) for fast analyzing fluorescence lifetime imaging (FLIM) data. A 1D CNN shows unparalleled advantages; they are more straightforward, quicker to train, and faster than high dimensional CNNs. 1D CNNs can be easily applied to multi-exponential fluorescence decay models. Compared with traditional

Multimodal optical microscopy combines different optical and physiological principles working together to obtain rich perspectives from a single biological event. In this paper, the recent advances in multimodal microscopy systems based on off-axis digital holography and transport-of-intensity equation are reviewed. Both methods used the common-path configuration, and realized simultaneous quantitative

The present study investigated age-related changes in the time-varying hemodynamics of the prefrontal cortex by using near-infrared spectroscopy (NIRS). NIRS is a real-time spectroscopic method used to measure functional hemodynamic responses related to neural activation in the brain. The prefrontal hemodynamic responses of 17 young adults and 21 elderly adults were monitored while they completed the

An ultra-wide detection range refractive-index sensor based on surface plasmon resonance (SPR) with photonic crystal fiber (PCF) is designed and discussed. The central air-hole of the fiber is injected with the analyte. The properties of refractive-index sensor are investigated with different structure parameters. Simulation results show that the proposed sensor has an ultra-wide detection range from

The effects of chemotherapy on the tumor microenvironment remain poorly investigated, although these are crucial for the drug delivery and anti-tumor activity and can modify physiological behavior of cancer cells. Optical coherence angiography and phosphorescence lifetime spectroscopy are promising optical methods to characterize both tumor vasculature and its oxygenation, respectively. In this study

Photoacoustic dermoscopy (PAD) has been proven to visualize the microvascular network within the dermis noninvasively, and has great application potential and advantages. In practice, some subjects are children or unwell and may have difficulty in controlling their breathing or trembling. The artifacts caused by the uncontrollable trembling will degrade the image quality, resulting in deviation of

We introduce a method for reconstructing phase objects in optical diffraction tomography (ODT) based on regularized convex optimization with a new phase-based fidelity criterion. The new criterion is necessary because objects of different refractive-index distributions may produce similar diffracted fields (magnitude and principal-phase) on the detection planes. This surjective, but non-injective relation

Surface-enhanced Raman scattering (SERS) technique can increase the Raman signals of the analytes owing to the electric field enhancements on the nanostructures. The strong light intensity, called photonic nanojet, can be formed at the backlight of the dielectric microstructures. Recently, some researchers have applied the photonic nanojets in SERS. In this paper, a layer of synthesized low-cost polystyrene

The successful surgery of chronic otitis media (COM) is challenging; this depends on the surgeon's knowledge of the optical visibility of surgical microscopes. Herein, we reported the utilization of intra-surgical optical coherence tomography (OCT) system to effectively guide the surgery of COM based on augmented reality with cross-sectional images. The intra-surgical spectral-domain OCT system with

An antibody modified terahertz (THz) metamaterial biosensor is proposed to detect the concentration of carcinoembryonic antigen (CEA). The biosensor has four metal split-ring-resonators (SRR) in a unit cell. The finite integration time domain (FITD) method is used to design and optimize the structure. The simulation shows that the biosensor is insensitive to incident angles and the sensitivity reaches

Light sheet fluorescence microscopy has become a basic tool in biology and medical research with its fast imaging speed, low phototoxicity and high spatiotemporal resolution. Here, we report a novel method to generate multiplane parallel light sheets with a micro structure named isosceles triangular array. The thickness of light sheet in each plane can approach 3.12 μm along with the working distance

Stable output and beam profile at high power laser operation is a prime requirement for precision high-end manufacturing. The stability of laser charateristics during power scaling in a single-oscillator is limited by several unavoidable non-linear effects. Hence, kW-level power scaling through multiple amplification stages or using signal combination are feasible solutions. In a master oscillator

This paper presents a beyond 5G fronthaul network with dynamic beamforming and -steering. The proposed fronthaul solution deploys optical beamforming (OBF) by combining space division multiplexing (SDM), analogue radio-over-fiber (ARoF), and the novel optical beam forming network (OBFN) technologies. From the service management and orchestration (MANO) point of view, the proposed fronthaul solution

This work addresses the role of optical sensing within the new emerging paradigm Industry 4.0 . It starts with some thoughts about complex systems and their inherent need of enlarged sensorial tools. Then, the principles of optical sensing are presented with identification of the two principal types. After summarizing what is meant by Industry 4.0 , it is detailed how optical sensing can contribute

The many tunable parameters involved in laser processing, such as wavelength, pulse duration, pulse energy, and scan speed, not to mention various other complicating factors on the material side, makes it practically impossible to reliably find an optimized parameter set to realize a specific processing target. Currently, an acceptable parameter set is mainly found by tapping the experience and intuition

This paper presents an overview of recent developments in smartphone spectrometers focusing on light collection, dispersion, detection and spectral calibration. These spectrometers potentially offer unprecedented field diagnostics that can exploit real-time IoT edge data transfer into the cloud and back. However, there are technical challenges if these are to perform as well, if not better, than laboratory-based

A novel interrogation method is presented in the application of strain sensing with a double taper Mach-Zehnder interferometer (DTMZI). The proposed sensing setup comprises a laser source and an optical power meter, which significantly lowers future integration cost and complexity. An analytical coupling model is established to study the sensor's strain-related modal behaviour. The design parameters

Plasma spectroscopic techniques focused on the analysis of the plasma background radiation have been studied to enable an efficient on-line monitoring of a laser metal deposition process. The influence of different process parameters and elements, such as laser power, process speed, powder feeding rate and different powder and substrate compositions has been analyzed by means of several experimental

In this work, a multi-parameter point sensor based on the combination of Fabry-Perot (FP) and the anti-resonant (AR) reflecting guidance in cascade configuration is proposed and experimentally demonstrated. This structure, based on FP interference and AR reflecting guidance, was fabricated with two different air micro-cavities. The attained experimental results showed different strain and temperature

Vortex beams (VBs), characterized by helical phase front and orbital angular momentum (OAM), have shown perspective potential in improving communication capacity density for providing an additional multiplexing dimension. Here, we propose a diffractive deep neural network (D 2 NN) method for OAM mode multiplexing and demultiplexing. By designing the D 2 NN model and simulating light propagation through

A minimum mean squared error (MMSE) equalizer is a way to effectively increase transmission performance for nonlinear Fourier transform (NFT) based communication systems. Other equalization schemes, based on nonlinear equalizer approaches or neural networks, are interesting for NFT transmission due to their ability to deal with nonlinear correlations of the NFTs’ eigenvalues and their coefficients

Electro-optic modulators are utilized ubiquitously ranging from applications in data communication to photonic neural networks. While tremendous progress has been made over the years, efficient phase-shifting modulators are challenged with fundamental tradeoffs, such as voltage-length, index change-losses or energy-bandwidth, and no single solution available checks all boxes. While voltage-driven phase

The purpose of this paper is twofold. First, we discuss the efficiency-speed tradeoff in slow-light (SL) silicon photonic (SiP) modulators. For this, a comprehensive model for the electro-optic (EO) response of lumped-electrode SL Mach-Zehnder modulators (SL-MZMs) is presented. The model accuracy is verified by comparing it to experiments. Our analysis shows that slowing down the optical wave helps

Hybrid Lithium Niobate (LN) and Silicon photonic (SiPh) integration platform has emerged as a promising candidate to combine the scalability of silicon photonics with the excellent modulation performance of LN. Mach-Zehnder modulators (MZMs) based on this platform exhibit outstanding performance with low insertion loss, low drive voltage, and large bandwidth. In this paper, we discuss the technologies

The all-optical cross-wavelength quadrature amplitude modulation orthogonal frequency-division multiplexing (QAM-OFDM) data switching in the silicon rich silicon carbide (Si-rich SiC) micro-ring (μ-ring) waveguide is demonstrated for the first time by using the two-photon absorption (TPA) induced free carrier absorption (FCA) process. With enlarging the allowable 4-QAM OFDM data bandwidth to 1.16 GHz

This paper presents our technological approach for Externally Modulated Lasers (EMLs), based on Semi-Insulating Buried Heterostructure (SIBH) waveguide. We use Gas Source Molecular Beam Epitaxy (GSMBE) to grow the Phosphorus-based multi-quantum wells for both laser and modulator sections with butt-joint integration. The same GSMBE grows the p-doped InP claddings with low-diffusion Be dopant, leading

Silicon photonics has become an industrial reality for datacom applications. Nevertheless, as Si suffers from a low electro-optic effect, commercial modulators are few-mm long. The efficiency can be enhanced by using strained-SiGe or by using a semiconductor insulator semiconductor (SIS) architecture. In this paper, we develop a model based on a perturbative approach to optimize capacitive modulator

For next-era optical interconnects in data centers, development of compact, energy-efficient, low-cost, and high-speed optical transceivers are required, for which high-performance external modulators in silicon photonics will be key components. We present a silicon photonic crystal waveguide slow light Mach-Zehnder modulator suitable for this purpose. The enhancement in the modulation efficiency via

Silicon Mach-Zehnder modulators (MZMs) utilizing carrier depletion usually adopt traveling-wave (TW) electrodes for their long phase shifters, which have inherent challenges in miniaturization, limiting the integration density of monolithic transceivers. In this work, we experimentally demonstrate non-TW carrier-depletion MZMs that give better compromises between compact footprint, modulation depth

Silicon photonics is a key-enabling technology leveraging decades of effort and infrastructure of the microelectronics CMOS industry resulting in high yield, low cost and potential high volume manufacturing. Furthermore, due to the high index contrast of the platform, very compact, high-complexity photonic integrated circuits can be devised. To benefit from these advantages, high-speed modulators should

A novel maximum-ratio combined receiver (MRC-RX) is proposed and demonstrated through a proof-of-concept experiment, conducted to mitigate the system performance degradation caused by the low linearity of the silicon modulator when deployed in passive optical network (PON)-based access. By employing the proposed MRC-RX, an optimized receiver sensitivity is achieved, which enables the mitigation of

Realization of on-board and inter-chip optical interconnects requires a photonic data link with power consumption well below their electrical counterparts (i.e., <<1 pJ/bit). Currently, directly modulating 850 nm vertical cavity surface emitting lasers at >50 Gb/s requires 2–4 pJ/bit/channel. External reverse-biased modulators could drastically reduce this power consumption. Here we design ultralow

Sinc-shaped Nyquist pulses have wide applications in optical communications and microwave photonics. The quality of the generated Nyquist pulses has a significant effect on the overall performance of the communication system and the signal processing system. Generating high-quality Nyquist pulses with integrated silicon modulators is however still challenging due to the highly nonlinear response and

Based on femtosecond laser ablated processing, one-dimensional arrays with different line spacings were fabricated on titanium disulfide (TiS2) nanosheet. Optical modulated measurements with these devices were demonstrated. Photo-induced complex conductivity changes of the TiS2 nanosheet devices were studied by an optical-pump THz-probe (OPTP) measurement system. For the 700 μm line spacing device

In the past few years, Brillouin-based optical fiber sensors have gained significant ground for distributed temperature and strain measurements in the real world. Among these sensors, the optical chirp chain (OCC) based Brillouin optical fiber sensor is a good candidate to realize ultrafast distributed sensing, which is of great importance to distinguish quick-changing events in practical applications

Multi-photon lithography -a powerful laser nanoscale additive-manufacturing method- is employed for structuring micro-ring traveling-wave resonators onto micrometric diameter, optical fiber tapers. These weakly guided, micro-ring resonating structures achieve light circulation with Q-factors of the order of ∼2.0 × 10 3 , for typical diameters of tens of micrometers, in the spectral band of 1550 nm

This paper highlights certain optical signal processing (OSP) functions that can be achieved when using optical frequency combs. An optical frequency comb can provide many narrow-linewidth, mutually coherent, and equidistant optical carriers, making it a potentially useful tool for facilitating efficient signal processing functions. In this paper, we explore the following general topics: (a) tailoring

Silicon core fibers represent a versatile platform for all-fiber integrated nonlinear optical applications. This paper describes the state of the art in four-wave mixing-based parametric amplification, and wavelength conversion in silicon fibers that have been tapered to improve the material quality, and engineer the dispersion profile. Fibers with submicron core dimensions have been fabricated, and