
Bai-Ou GuanJinan University · Institute of Photonics Technology
Bai-Ou Guan
Ph.D.
About
593
Publications
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10,448
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Introduction
Additional affiliations
April 2009 - present
Education
September 1997 - July 2000
September 1994 - July 1997
September 1990 - July 1994
Publications
Publications (593)
A label-free fiber-optic biosensor with a reflective microfiber Bragg grating (mFBG) configuration for in-situ DNA hybridization detection has been proposed and experimentally demonstrated. A single straight Bragg grating inscribed in the silica microfiber provides two well-defined resonances in reflection, which show different response to external...
We demonstrate four-port long-period gratings formed by winding an
optical microfiber with another thinner microfiber. The surrounding
thinner microfiber not only induces a strong refractive-index
perturbation in the center microfiber, but also collects and leads out
the light resonantly coupled from the fundamental mode to high-order
modes, provid...
Microfiber Bragg gratings (mFBGs) are of great promise due to their compactness, large evanescent field effect, low stiffness, and good flexibility. A lot of researches related to the fabrication and the potential applications of mFBGs in sensing and communication have been made in the past. This review begins from the theoretical analysis based on...
Fiber grating laser sensors have been attracting interest because of their high signal-to-noise ratio and narrow linewidth that permit high resolution sensing. According to the working principle, fiber grating laser sensors can be classified into two types: wavelength encoding sensor and polarimetric heterodyning sensor. The former converts measurr...
Local microcurrent monitoring is of great significance for biological and battery systems, yet it poses a formidable challenge. The current measurement techniques rely on electromagnetic materials which inevitably introduce interference to the system under examination. To address this issue, a promising approach based on a dielectric fiber-optic se...
Semiconductor metal oxides with narrow bandgap have emerged as a promising platform for photoelectrochemical reactions, yet their photoelectron-induced photocorrosion effect has been a limitation for their wider applications. Understanding the conversion processes concomitant with photoelectrochemical reaction at the electrode–electrolyte interface...
Despite the great success in deploying metal‐organic frameworks (MOFs) as efficient electrocatalysts, the low adoption of operando methods hinders the understanding of underlying mechanism. By leveraging the subtle refractive index evolution, including both the real and the imaginary parts, an entirely new concept of a lab‐on‐fiber operando method...
Efficient delivery of photons to visceral organs is critical for the treatment of deep‐seated tumors taking advantage of photo theranostics. Optical fiber can be regarded as a direct and facile photon pathway for targeting tumor lesion. However, current fiber theranostic strategies rely on the spatially separated optical fibers to realize diagnosis...
Noninvasive high-resolution deep-brain imaging is essential to fundamental cognitive process study and neuroprotective drugs development. Although optical microscopes can resolve fine biological structures with good contrast without exposure to ionizing radiation or a strong magnetic field, the optical scattering limits the penetration depth and hi...
A new microwave photonic signal processor for use in a frequency diverse array (FDA) to generate a dot-shaped beampattern is presented. The microwave photonic signal processor is implemented based on a dual-polarization quadrature phase shift keying (DP-QPSK) modulator and a phase modulator (PM), with the amplitude and phase of an input radio frequ...
Monolayer transition metal dichalcogenides (TMDCs) have extensive applications in the field of optics and optoelectronics by virtue of their unique band structures and excitonic properties. Although possessing high absorption coefficient and emission efficiency, they suffer from low optical absorptance due to the atomic scale thickness, which limit...
Seven-core fibers have been widely applied in optical network, astronomy, and sensing applications. In this work, we report and demonstrate the existence of triple dispersion turning points of the super-mode interferences in a seven-core fiber spliced between two single-mode fibers by modifying the diameter of the multi-core fiber. The sensitivitie...
Chemotherapy is one of the conventional treatments for cancer in clinical practice. However, poor delivery efficiency, systemic toxicity, and the lack of pharmacokinetic monitoring during treatment are the critical limitations of current chemotherapy. Herein, we reported a brand-new antitumor drug delivery strategy that harnesses an optical fiber e...
This article presents the distinctive butyrylcholinesterase (BChE) fluorescent probe P5, designed via a targeting-site method. This method was proposed to enhance the affinity of the probe for BChE by targeting the peripheral anionic site (PAS) of BChE. By mimicking the natural substrate butyrylcholine, the structure of the probe was optimized by i...
Breast cancer often necessitates surgical interventions such as breast-conserving surgery or mastectomy. In these surgeries, sentinel lymph node (SLN) samples are often excised for histopathological examination to ascertain the presence of cancer metastasis. Despite its importance, traditional hematoxylin and eosin (H&E) staining, considerably prol...
Glass ceramics (GCs) containing PbS quantum dots (QDs) are prepared for temperature sensing. Broadband emissions are detected in the GCs when PbS QDs are precipitated from the glasses, and emissions centers are modulated from 1250 nm to 1960 nm via heat treatments. The emission centers of GCs exhibit blue-shifts when environment temperatures increa...
Efficient delivery of photons to visceral organs is critical for the treatment of deep-seated tumors taking advantage of photo-theranostics. Optical fiber can be regarded as a direct and facile photon pathway for targeting tumor lesion with negligible body invasion. However, current fiber theranostic strategies rely on the spatially separated optic...
In this paper, cascaded modal interferometers constructed by strongly-coupled seven-core fiber (SC-SCF) with different lengths are demonstrated for enhanced bending sensing based on Vernier effect. The free spectral range (FSR) of a single SC-SCF interferometer is determined by the length of SC-SCF. Two SC-SCF interferometers with different FSRs ar...
Cancer has been one of the most serious diseases, resulting in more than 10 million deaths every year. Fiber-optic sensors have great potential for diagnosing and treating cancer due to their flexibility, precise positioning, real-time monitoring, and minimally invasive characteristics. Compared to traditional central laboratory examination, fiber-...
Optical fiber-based photothermal devices show great promise for applications in in vivo detection and therapy. The integration of sensors and actuators in one fiber is a feasible method to orchestrate both functionalities. However, the photoheating-induced temperature field is not always homogeneous in the practical application, which undermines th...
Invasive fungal infections pose a significant public health threat. The lack of precise and timely diagnosis is a primary factor contributing to the significant increase in patient mortality rates. Here, an interface‐modulated biosensor utilizing an optical fiber for quantitative analysis of fungal biomarkers at the early stage of point‐of‐care tes...
In this paper, cascaded modal interferometers constructed by strongly-coupled seven-core fiber (SC-SCF) with different lengths are demonstrated for enhanced bending sensing based on Vernier effect. The free spectral range (FSR) of a single SC-SCF interferometer is determined by the length of SC-SCF. Two SC-SCF interferometers with different FSRs ar...
In this paper, cascaded modal interferometers constructed by strongly-coupled seven-core fiber (SC-SCF) with different lengths are demonstrated for enhanced bending sensing based on Vernier effect. The free spectral range (FSR) of a single SC-SCF interferometer is determined by the length of SC-SCF. Two SC-SCF interferometers with different FSRs ar...
Optical microscopy is indispensable to biomedical research and clinical investigations. As all molecules absorb light, optical-resolution photoacoustic microscopy (PAM) is an important tool to image molecules at high resolution without labeling. However, due to tissue-induced optical aberration, the imaging quality degrades with increasing imaging...
Oxyfluoride transparent glass‐ceramics (GC) are widely used as the matrix for rare‐earth (RE) ions due to their unique properties such as low phonon energy, high transmittance, and high solubility for RE ions. Tb³⁺ doped oxyfluoride glasses exhibit a large absorption cross section for ultraviolet (UV) excitation, high stability, high photoluminesce...
We report the development of a head-mounted photoacoustic fiberscope for cerebral imaging in a freely behaving mouse. The 4.5-gram imaging probe has a 9-µm lateral resolution and 0.2-Hz frame rate over a 1.2-mm wide area. The probe can continuously monitor cerebral oxygenation and hemodynamic responses at single-vessel resolution, showing significa...
Optical microcavities with high quality factors can significantly enhance the intracavity power density and have become a superior platform for studying quantum electrodynamics, nonlinearities, and sensing. Minimized and compact on-chip devices require the integration of microcavities with versatile functions that can be implemented by techniques c...
The use of light as a powerful tool for disease treatment has introduced a new era in tumor treatment and provided abundant opportunities for light‐based tumor theranostics. This work reports a photothermal theranostic fiber integrating cancer detection and therapeutic functions. Its self‐heating effect can be tuned at ultralow powers and used for...
Hydrogels are an important category of polymeric materials with physicochemical features such as moisturizability and biocompatibility that are ideal for developing dressings for diabetic wounds. However, conventional non-ionic hydrogel materials generally exhibit poor mechanical properties and poor adhesion, which compromise their ability to self-...
Dynamic access to quasi-bound states in the continuum (q-BICs) offers a highly desired platform for silicon-based active nanophotonic applications, while the prevailing tuning approaches by free carrier injections via an all-optical stimulus are yet limited to THz and infrared ranges and are less effective in visible bands. In this work, we present...
Hydrogen (H2) sensors are critical to various applications such as the situation where H2 is used as the clean energy for industry or the indicator for human disease diagnosis. Palladium (Pd) is widely used as the hydrogen sensing material in different types of sensors. Optical fiber H2 sensors are particularly promising due to their compactness an...
Synthetic dimension opens new horizons in quantum physics and topological photonics by enabling new dimensions for field and particle manipulations. The most appealing property of the photonic synthetic dimension is its ability to emulate high-dimensional optical behavior in a unitary physical system. Here we show that the photonic synthetic dimens...
With the recent advances in nanomaterials, photothermal therapies (PTT) enabled by deep-tissue penetration with novel nanoagents have offered a new hope for treating cancers. Nevertheless, PTT applications in conventional approaches remain translationally restricted due to their non-specificity and collateral pro-inflammatory effects during impleme...
Optical fibers can be effective biosensors when employed in early-stage diagnostic point-of-care devices as they can avoid interference from molecules with similar redox potentials. Nevertheless, their sensitivity needs to be improved for real-world applications, especially for small-molecule detection. This work demonstrates an optical microfiber...
Fiber-optic grating biosensor offers compelling advantages such as compact footprint and nature of signal reflection, and thus becomes a particularly apt candidate for cardiovascular biomarker determination. However, limit of detection (LOD), test speed, and maneuverability of such biosensor should be substantially improved before conferring those...
Helical-core fibers have been widely utilized for various applications such as orbital angular momentum manipulation, optical filtering, and sensing. In this work, we demonstrate the sensitivity enhancement of a helical-core fiber by tailoring the resonance wavelength towards the dispersion turning point (DTP) utilizing a post chemical etching proc...
A temperature-compensated refractive index (RI) sensor based on thinned strongly-coupled seven-core fiber (SC-SCF) supermode Bragg grating and interferometer is demonstrated. The SC-SCF spliced between two standard single mode fibers was first tapered to 55.0 μm and then chemically etched to a waist diameter of 15.6 μm, forming a supermode interfer...
We report the development of a head-mounted photoacoustic fiberscope for cerebral imaging in a freely behaving mouse. The 4.5-gram imaging probe has a 9-µm lateral resolution and 0.2-Hz frame rate over a 1.2-mm wide area. The probe can continuously monitor cerebral oxygenation and hemodynamic responses at single-vessel resolution, showing significa...
Humidity plays an important role in many fields, and the realization of high sensitivity and fast response simultaneously for humidity detection is a great challenge in practical application. In this work, we demonstrated a high-performance relative humidity (RH) sensor made by supporting zeolitic imidazolate framework-90 (ZIF-90)-derived porous zi...
Optical fiber acoustic sensors with miniature size and high sensitivity are attractive to develop compact photoacoustic spectroscopy. Here, a compact photoacoustic gas sensor was demonstrated by utilizing a diaphragm-based fiber-optic Fabry-Perot cavity as both the acoustic sensor and the multipass cell. A nanoscale graphite film was used as the fl...
Capacitive deionization in environmental decontamination has been widely studied and now requires intensive development to support large-scale deployment. Porous nanomaterials have been demonstrated to play pivotal roles in determining decontamination efficiency and manipulating nanomaterials to form functional architecture has been one of the most...
Plasmonic sensors leverage the enhanced near-fields associated with the constituent optical nanoantennas to achieve better sensing performance. The design and fabrication of these optical nanoantennas, especially metallic ones, are thus becoming critical steps to advance this thriving and important field. Low-cost and high-throughput nanofabricatio...
Fiber-optic devices working in the visible and near-infrared windows are attracting attention due to the rapid development of biomedicine that involves optics. In this work, we have successfully realized the fabrication of near-infrared microfiber Bragg grating (NIR-µFBG), which was operated at the wavelength of 785 nm, by harnessing the fourth har...
The optical generation of pulsed ultrasound is attractive to nondestructive testing and biological imaging, especially for those involving narrow operation space or strong electro-magnetic interference. However, conventional techniques based on the photoacoustic effect inevitably required an expensive high-energy short pulsed laser and dedicated pr...
All-optical ultrasound manipulates ultrasound waves based on laser and photonics technologies, providing an alternative approach for pulse-echo ultrasound imaging. However, its endoscopic imaging capability is limited ex vivo by the multifiber connection between the endoscopic probe and the console. Here, we report on all-optical ultrasound for in...
Wearable sensing devices, which can find tremendous applications in healthcare and automation, are attracting great attention in recent years. Herein, we report a flexible wearable optical sensor (FWOS) which consists of the microfiber Bragg grating (μFBG) as the core sensing node and a ductile PDMS film
as the sensor encapsulation. Due to the stra...
Photoacoustic tomography emerged as a promising tool for noninvasive biomedical imaging and diseases diagnosis. However, most of the current piezoelectric ultrasound transducers suffer optical opacity and tissue-mismatched acoustic impedance, hindering the miniaturization and integration of the system for multiscale and multimodal imaging. Here, a...
The use of light, which is s a powerful tool for imaging and sensing, has also become one of the most prospective strategies in tumor treatment. Optical microfibers, which have engineerable waveguiding properties, are highly attractive for optical sensing and photothermal therapy on the micro/nanoscale. However, for their real‐world application, th...