Retrieving high-fidelity images from optical speckles remains challenging,especially when the information in speckles is severely insufficient.To address classification through scattering media under such constraints,...Retrieving high-fidelity images from optical speckles remains challenging,especially when the information in speckles is severely insufficient.To address classification through scattering media under such constraints,we propose Speckle Transformer,a vision-transformer-based model that directly classifies objects using raw speckle patterns without intermediate image retrieval.By leveraging inherent features within speckles to extract discriminative features,our approach achieves nearly 90%accuracy for classifying speckles encoded with different images,outperforming traditional retrieval-classification pipelines by up to five times,even with extreme information sparsity(i.e.,1/1024 speckle regions of interest).In addition,we quantify speckle information capacity via information entropy analysis,demonstrating that classification accuracy correlates strongly with the information entropy of speckle autocorrelation.We not only overcome limitations of conventional methods but also establish a paradigm for real-time classification in scattering environments with constrained data.展开更多
Coherent optical control within or through scattering media via wavefront shaping has seen broad applications since its invention around 2007.Wavefront shaping is aimed at overcoming the strong scattering,featured by ...Coherent optical control within or through scattering media via wavefront shaping has seen broad applications since its invention around 2007.Wavefront shaping is aimed at overcoming the strong scattering,featured by random interference,namely speckle patterns.This randomness occurs due to the refractive index inhomogeneity in complex media like biological tissue or the modal dispersion in multimode fiber,yet this randomness is actually deterministic and potentially can be time reversal or precompensated.Various wavefront shaping approaches,such as optical phase conjugation,iterative optimization,and transmission matrix measurement,have been developed to generate tight and intense optical delivery or high-resolution image of an optical object behind or within a scattering medium.The performance of these modula-tions,however,is far from satisfaction.Most recently,artifcial intelligence has brought new inspirations to this field,providing exciting hopes to tackle the challenges by mapping the input and output optical patterns and building a neuron network that inherently links them.In this paper,we survey the developments to date on this topic and briefly discuss our views on how to harness machine learning(deep learning in particular)for further advancements in the field.展开更多
Wavefront shaping(WFS)techniques have been used as a powerful tool to control light propagation in complex media,including multimode fibers.In this paper,we propose a new application of WFS for multimode fber-based se...Wavefront shaping(WFS)techniques have been used as a powerful tool to control light propagation in complex media,including multimode fibers.In this paper,we propose a new application of WFS for multimode fber-based sensors.The use of a single multimode fiber alone,without any special fabrication,as a sensor based on the light intensity variations is not an easy task.The twist effect on multimode fiber is used as an example herein.Experimental results show that light intensity through the multimode fiber shows no direct relationship with the twist angle,but the correlation coefficient(CC)of speckle patterns does.Moreover,if WFS is applied to transform the spatially seemingly random light pattern at the exit of the multimode fiber into an optical focus.The focal pattern correlation and intensity both can serve to gauge the twist angle,with doubled measurement range and allowance of using a fast point detector to provide the feedback.With further development,WFS may find potentials to facilitate the development of multimode fber-based sensors in a variety of scenarios.展开更多
Photoacoustic(PA)imaging is a promising non-invasive and non-ionizing biomedical imaging modality that emerged in recent years.The articles presented in this special issue describe some of newest progress in this fiel...Photoacoustic(PA)imaging is a promising non-invasive and non-ionizing biomedical imaging modality that emerged in recent years.The articles presented in this special issue describe some of newest progress in this field.We are extremely grateful to all contributing authors.The first part of the issue covers new laser source devel-opment,including fiber lasers and laser diodes.The sec-ond part is dedicated to improving the image resolution through chronic cranial window techniques,virtual-point concept,fast polygon scanning,and Fabry Perot sensing.The third part shows the basic principles of photoacous-tic/ultrasound imaging and its applications.展开更多
Multimodal imaging-guided chemo-photothermal therapy is an excellent cancer treatment,which can not only efficiently against tumor,but also can offer precise treatment window and real-time monitoring of the treatment ...Multimodal imaging-guided chemo-photothermal therapy is an excellent cancer treatment,which can not only efficiently against tumor,but also can offer precise treatment window and real-time monitoring of the treatment efficiency.In our work,polydopamine(PDA)-coated gold nanobones(AuNBs@PDA nanocomplexes)were designed for this approach.The AuNBs@PDA nanocomplexes have strong absorbance in the near infrared(NIR)region and higher photothermal conversion efficiency(75.48%)than gold nanobones alone,which was facilitated for photoacoustic imaging and photothermal therapy.Besides,the loading efficiency of doxorubicin(DOX)by AuNBs@PDA nanocomplexes could be up to about 70%and DOX release from AuNBs@PDA/DOX nanocomplexes sensitively response to the lower pH environment and NIR laser irradiation,which makes them become the excellent nano-carrier for the delivery of chemotherapy drug.In vitro and in vivo studies showed significant cytotoxicity and antitumor efficacy by the AuNBs@PDA/DOX nanoplatform with negligible side effects.Meanwhile,the nanoplatform was also successfully employed for computed tomography(CT)imaging,attributing to the high atomic number and high X-ray attenuation coefficient of gold.Therefore,we believed that the proposed PDA-coated gold nanobones would be a novel multifunctional theranostic nanoagent to realize the PA/CT imaging-guided chemo-photothermal therapy of cancer.展开更多
Graphene derivatives,possessing strong Raman scattering and near-infrared absorption intrin-sically,have boosted many exciting biosensing applications.The tunability of the absorption characteristics,however,remains l...Graphene derivatives,possessing strong Raman scattering and near-infrared absorption intrin-sically,have boosted many exciting biosensing applications.The tunability of the absorption characteristics,however,remains largely unexplored to date.Here,we proposed a multilayer configuration constructed by a graphene monolayer sandwiched between a buffer layer and one-dimensional photonic crystal(1DPC)to achieve tunable graphene absorption under total in-ternal reflection(TIR).It is interesting that the unique optical properties of the buffer-graphene-1DPC multilayer structure,the electromagnetically induced transparency(EIT)-like and Fano-like absorptions,can be achieved with pre-determined resonance wavelengths,and furtherly be tuned by adjusting either the structure parameters or the incident angle of light.Theoretical analyses demonstrate that such EIT-and Fano-like absorptions are due to the interference of light in the multilayer structure and the complete transmission produced by the evanescent wave resonance in the configuration.The enhanced absorptions and the huge electrical field en-hancement effect exhibit potentials for broad applications,such as photoacoustic imaging and Raman imaging.展开更多
Transmission matrix(TM)allows light control through complex media,such as multimode fibers(MMFs),gaining great attention in areas,such as biophotonics,over the past decade.Efforts have been taken to retrieve a complex...Transmission matrix(TM)allows light control through complex media,such as multimode fibers(MMFs),gaining great attention in areas,such as biophotonics,over the past decade.Efforts have been taken to retrieve a complex-valued TM directly from intensity measurements with several representative phase-retrieval algorithms,which still see limitations of slow or suboptimum recovery,especially under noisy environments.Here,we propose a modified nonconvex optimization approach.Through numerical evaluations,it shows that the optimum focusing efficiency is approached with less running time or sampling ratio.The comparative tests under different signal-to-noise levels further indicate its improved robustness.Experimentally,the superior focusing performance of our algorithm is collectively validated by single-and multispot focusing;especially with a sampling ratio of 8,it achieves a 93.6%efficiency of the gold-standard holography method.Based on the recovered TM,image transmission through an MMF is realized with high fidelity.Due to parallel operation and GPU acceleration,our nonconvex approach retrieves a 8685×1024 TM(sampling ratio is 8)with 42.3 s on average on a regular computer.The proposed method provides optimum efficiency and fast execution for TM retrieval that avoids the need for an external reference beam,which will facilitate applications of deep-tissue optical imaging,manipulation,and treatment.展开更多
Optical technologies have been increasingly utilized in biomedicine,including diagnosis,therapy,and surgery.In almost all of these applications,photons need to propagate some distance in tissue.Therefore,the capabilit...Optical technologies have been increasingly utilized in biomedicine,including diagnosis,therapy,and surgery.In almost all of these applications,photons need to propagate some distance in tissue.Therefore,the capability of focusing or demodulating light information plays an essential role,largely determining the sensitivity and spatial resolution of these techniques.This has always been desired yet considered challenging within or through thick biological tissues due to the strong scattering of light.展开更多
Fiber-structured ion sensors have gained traction in health monitoring and medical diagnostics owing to their structural flexibility,enhanced sensitivity,and suitability for integration into wearable devices.This stud...Fiber-structured ion sensors have gained traction in health monitoring and medical diagnostics owing to their structural flexibility,enhanced sensitivity,and suitability for integration into wearable devices.This study employed a simple and efficient solutionbased process to fabricate nanofibers containing aggregation-induced emission(AIE)dyes.The resulting AIE nanofibers exhibited stable and intense fluorescence,nanosecond fluorescence lifetime,and low-loss light transport when functioning as active waveguides.Additionally,crossed nanofiber intersections exhibited diffraction-limited emission spots.The AIE nanofibers demonstrate efficient and ionspecific fluorescence quenching in response to Ag^(+).These results support the development of sensing units capable of operating in liquid environments or in direct contact with skin or tissues,facilitating real-time monitoring of ion concentrations for personalized healthcare management.展开更多
Flexible electronic skins hold great promise for biomedical applications,although challenges remain in achieving controllable interactions with the biological interface and accurate signal collection.Inspired by octop...Flexible electronic skins hold great promise for biomedical applications,although challenges remain in achieving controllable interactions with the biological interface and accurate signal collection.Inspired by octopuses and chameleons,we propose a novel electronic skin paradigm with on-demand adhesion and opto-electronic synergistic display capabilities.Our electronic skins are composed of a stretchable polyurethane(PU)inverse opal film integrated with a carbon nanotube(CNT)-hybridized polyacrylamide(PAAm)-gelatin double-network-hydrogel conductive flexible substrate and a temperature-responsive poly(N-isopropylacrylamide)(PNIPAm)octopus-inspired hemispherical adhesive array.The device’s CNT hybrid double-network provides robust and sensitive monitoring of temperature and motion.Meanwhile,its flexible PU layer with an inverse opal structure allows for visual motion color sensing.Integrated neural network processing ensures accurate,wide-range,and independent multimodal display.Additionally,the integration of the photothermal effect of CNTs and the temperaturesensitive octopus-inspired PNIPAm adhesive array enables on-demand adhesion.The sensing and adhesion demonstrations ex vivo and in vivo showcase the proposed flexible electronic skin’s inspirational design and functional utilities.The potential applications of such a versatile device are vast,ranging from healthcare to human-machine interactions.展开更多
Biomedical patches have demonstrated value in promoting soft tissue repair or anti-adhesion.Research tendency in this area focuses on developing more controllable patches to meet the complex clinical scenarios.Herein,...Biomedical patches have demonstrated value in promoting soft tissue repair or anti-adhesion.Research tendency in this area focuses on developing more controllable patches to meet the complex clinical scenarios.Herein,inspired by the controllable adhesion of suction cups and the antifouling properties of eyeball surfaces,we propose an anisotropic patch with‘revocable’adhesion mechanisms.For the adhesive-side,the initial adhesion forces mainly rely on suction cup’s physical interactions to allow adequate position adjustment,followed by the reaction of N-hydroxysuccinimide ester group with the tissue for firm covalent bonding.This multi-adhesive mechanism enables the spatiotemporal control of adhesive behavior.In contrast,on the barrier-side,the highly hydrated surface derived from polyethylene glycol and polyvinyl alcohol hydrogels displays no affinity for tissue proteins,thus effectively preventing tissue adhesion.Moreover,the intrinsic pores and charges enable the adsorption of positively charged inflammatory factors,while the loaded drugs can release sustainably.In vivo experiments demonstrate the patch’s strong yet controllable adhesion,effective in reducing inflammation and promoting healing.This innovative design introduces a new paradigm of‘revocable’adhesion,offering significant clinical potential for soft tissue repair and adhesion prevention.展开更多
Optical focusing through scattering media is of great significance yet challenging in lots of scenarios,including biomedical imaging,optical communication,cybersecurity,three-dimensional displays,etc.Wavefront shaping...Optical focusing through scattering media is of great significance yet challenging in lots of scenarios,including biomedical imaging,optical communication,cybersecurity,three-dimensional displays,etc.Wavefront shaping is a promising approach to solve this problem,but most implementations thus far have only dealt with static media,which,however,deviates from realistic applications.Herein,we put forward a deep learning-empowered adaptive framework,which is specifically implemented by a proposed Timely-Focusing-Optical-Transformation-Net(TFOTNet),and it effectively tackles the grand challenge of real-time light focusing and refocusing through time-variant media without complicated computation.The introduction of recursive fine-tuning allows timely focusing recovery,and the adaptive adjustment of hyperparameters of TFOTNet on the basis of medium changing speed efficiently handles the spatiotemporal non-stationarity of the medium.Simulation and experimental results demonstrate that the adaptive recursive algorithm with the proposed network significantly improves light focusing and tracking performance over traditional methods,permitting rapid recovery of an optical focus from degradation.It is believed that the proposed deep learning-empowered framework delivers a promising platform towards smart optical focusing implementations requiring dynamic wavefront control.展开更多
Optical imaging through or inside scattering media, such as multimode fiber and biological tissues, has a significant impact in biomedicine yet is considered challenging due to the strong scattering nature of light. I...Optical imaging through or inside scattering media, such as multimode fiber and biological tissues, has a significant impact in biomedicine yet is considered challenging due to the strong scattering nature of light. In the past decade, promising progress has been made in the field, largely benefiting from the invention of iterative optical wavefront shaping, with which deep-tissue high-resolution optical focusing and hence imaging becomes possible. Most of the reported iterative algorithms can overcome small perturbations on the noise level but fail to effectively adapt beyond the noise level, e.g., sudden strong perturbations. Reoptimizations are usually needed for significant decorrelation to the medium since these algorithms heavily rely on the optimization performance in the previous iterations. Such ineffectiveness is probably due to the absence of a metric that can gauge the deviation of the instant wavefront from the optimum compensation based on the concurrently measured optical focusing.In this study, a square rule of binary-amplitude modulation, directly relating the measured focusing performance with the error in the optimized wavefront, is theoretically proved and experimentally validated. With this simple rule, it is feasible to quantify how many pixels on the spatial light modulator incorrectly modulate the wavefront for the instant status of the medium or the whole system. As an example of application, we propose a novel algorithm, the dynamic mutation algorithm, which has high adaptability against perturbations by probing how far the optimization has gone toward the theoretically optimal performance. The diminished focus of scattered light can be effectively recovered when perturbations to the medium cause a significant drop in the focusing performance, which no existing algorithms can achieve due to their inherent strong dependence on previous optimizations. With further improvement, the square rule and the new algorithm may boost or inspire many applications, such as high-resolution optical imaging and stimulation, in instable or dynamic scattering environments.展开更多
Optical techniques offer a wide variety of applications as light-matter interactions provide extremely sensitive mechanisms to probe or treat target media.Most of these implementations rely on the usage of ballistic o...Optical techniques offer a wide variety of applications as light-matter interactions provide extremely sensitive mechanisms to probe or treat target media.Most of these implementations rely on the usage of ballistic or quasi-ballistic photons to achieve high spatial resolution.However,the inherent scattering nature of light in biological tissues or tissue-like scattering media constitutes a critical obstacle that has restricted the penetration depth of non-scattered photons and hence limited the implementation of most optical techniques for wider applications.In addition,the components of an optical system are usually designed and manufactured for a fixed function or performance.Recent advances in wavefront shaping have demonstrated that scattering-or component-induced phase distortions can be compensated by optimizing the wavefront of the input light pattern through iteration or by conjugating the transmission matrix of the scattering medium.展开更多
Information retrieval from visually random optical speckle patterns is desired in many scenarios yet considered challenging.It requires accurate understanding or mapping of the multiple scattering process,or reliable ...Information retrieval from visually random optical speckle patterns is desired in many scenarios yet considered challenging.It requires accurate understanding or mapping of the multiple scattering process,or reliable capability to reverse or compensate for the scattering-induced phase distortions.In whatever situation,effective resolving and digitization of speckle patterns are necessary.Nevertheless,on some occasions,to increase the acquisition speed and/or signal-to-noise ratio(SNR),speckles captured by cameras are inevitably sampled in the sub-Nyquist domain via pixel binning(one camera pixel contains multiple speckle grains)due to finite size or limited bandwidth of photosensors.Such a down-sampling process is irreversible;it undermines the fine structures of speckle grains and hence the encoded information,preventing successful information extraction.To retrace the lost information,super-resolution interpolation for such sub-Nyquist sampled speckles is needed.In this work,a deep neural network,namely SpkSRNet,is proposed to effectively up sample speckles that are sampled below 1/10 of the Nyquist criterion to well-resolved ones that not only resemble the comprehensive morphology of original speckles(decompose multiple speckle grains from one camera pixel)but also recover the lost complex information(human face in this study)with high fidelity under normal-and low-light conditions,which is impossible with classic interpolation methods.These successful speckle super-resolution interpolation demonstrations are essentially enabled by the strong implicit correlation among speckle grains,which is non-quantifiable but could be discovered by the well-trained network.With further engineering,the proposed learning platform may benefit many scenarios that are physically inaccessible,enabling fast acquisition of speckles with sufficient SNR and opening up new avenues for seeing big and seeing clearly simultaneously in complex scenarios.展开更多
High-resolution optical imaging through or within thick scattering media is a long sought after yet unreached goal.In the past decade,the thriving technique developments in wavefront measurement and manipulation do no...High-resolution optical imaging through or within thick scattering media is a long sought after yet unreached goal.In the past decade,the thriving technique developments in wavefront measurement and manipulation do not significantly push the boundary forward.The optical diffusion limit is still a ceiling.In this work,we propose that a scattering medium can be conceptualized as an assembly of randomly packed pinhole cameras and the corresponding speckle pattern as a superposition of randomly shifted pinhole images.The concept is demonstrated through both simulation and experiments,confirming the new perspective to interpret the mechanism of information transmission through scattering media under incoherent illumination.We also analyze the efficiency of single-pinhole and dual-pinhole channels.While in infancy,the proposed method reveals a new perspective to understand imaging and information transmission through scattering media.展开更多
Imaging through scattering media is valuable for many areas,such as biomedicine and communication.Recent progress enabled by deep learning(DL)has shown superiority especially in the model generalization.However,there ...Imaging through scattering media is valuable for many areas,such as biomedicine and communication.Recent progress enabled by deep learning(DL)has shown superiority especially in the model generalization.However,there is a lack of research to physically reveal the origin or define the boundary for such model scalability,which is important for utilizing DL approaches for scalable imaging despite scattering with high confidence.In this paper,we find the amount of the ballistic light component in the output field is the prerequisite for endowing a DL model with generalization capability by using a“one-to-all”training strategy,which offers a physical meaning invariance among the multisource data.The findings are supported by both experimental and simulated tests in which the roles of scattered and ballistic components are revealed in contributing to the origin and physical boundary of the model scalability.Experimentally,the generalization performance of the network is enhanced by increasing the portion of ballistic photons in detection.The mechanism understanding and practical guidance by our research are beneficial for developing DL methods for descattering with high adaptivity.展开更多
Time-gated reflection matrix(RM)has been successfully used for optical imaging deep inside Scattering media.Recently,this method was extended to enhance the spatiotemporal focusing of light ultra-deep inside scatterin...Time-gated reflection matrix(RM)has been successfully used for optical imaging deep inside Scattering media.Recently,this method was extended to enhance the spatiotemporal focusing of light ultra-deep inside scattering media.This is achieved by calibrating the decomposition of the RM with the Tikhonov regularization parameter to convert mutiply scattered photons that share the same time of flight with the singly scattered photons into singly scattered photons.Such a capability suggests a reshaping to the interaction mechanism between light and scattering media,which may beneft or inspire wide optical applications that desire enhanced spatiotemporal focusing of light at depths inside scattering media.展开更多
Multimode fibers(MMFs)are a promising solution for high-throughput signal transmission in the time domain.However,crosstalk among different optical modes within the MMF scrambles input information and creates seemingl...Multimode fibers(MMFs)are a promising solution for high-throughput signal transmission in the time domain.However,crosstalk among different optical modes within the MMF scrambles input information and creates seemingly random speckle patterns at the output.To characterize this process,a transmission matrix(TM)can be used to relate input and output fields.Recent innovations use TMs to manipulate the output field by shaping the input wavefront for exciting advances in deep-brain imaging,neuron stimulation,quantum networks,and analog operators.However,these approaches consider input/output segments as independent,limiting their use for separate signal processing,such as logic operations.Our proposed method,which makes input/output segments as interdependent,adjusts the phase of corresponding output fields using phase bias maps superimposed on input segments.Coherent superposition enables signal logic operations through a 15-m-long MMF.In experiments,a single optical logic gate containing three basic logic functions and cascading multiple logic gates to handle binary operands is demonstrated.Bitwise operations are performed for multi-bit logic operations,and multiple optical logic gates are reconstructed simultaneously in a single logic gate with polarization multiplexing.The proposed method may open new avenues for long-range logic signal processing and transmission via MMFs.展开更多
As an outstanding two-dimensional material,black phosphorene,has attracted significant attention in the biomedicine field due to its large surface area,strong optical absorption,distinct bioactivity,excellent biocompa...As an outstanding two-dimensional material,black phosphorene,has attracted significant attention in the biomedicine field due to its large surface area,strong optical absorption,distinct bioactivity,excellent biocompatibility,and high biodegradability.In this review,the preparation and properties of black phosphorene are summarized first.Thereafter,black phosphorene-based multifunctional platforms employed for the diagnosis and treatment of diseases,including cancer,bone injuries,brain diseases,progressive oxidative diseases,and kidney injury,are reviewed in detail.This review provides a better understanding of the exciting properties of black phosphorene,such as its high drug-loading efficiency,photothermal conversion capability,high'O2 generation efficiency,and high electrical conductivity,as well as how these properties can be exploited in biomedicine.Finally,the research perspectives of black phosphorene are discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.81930048 and 82330061)the Hong Kong Research Grant Council(Grant Nos.15217721,C7074-21GF,and 15125724)+4 种基金the Hong Kong Innovation and Technology Commission(Grant Nos.GHP/043/19SZ and GHP/044/19GD)the Guangdong Science and Technology Commission(Grant No.2019BT02X105)the Shenzhen Science and Technology Innovation Commission(Grant No.JCYJ20220818100202005)the Hong Kong Polytechnic University(Grant Nos.P0038180,P0039517,P0043485,and P0045762)the Fundamental Research Funds for the Central Universities(Grant No.QTZX25121).
文摘Retrieving high-fidelity images from optical speckles remains challenging,especially when the information in speckles is severely insufficient.To address classification through scattering media under such constraints,we propose Speckle Transformer,a vision-transformer-based model that directly classifies objects using raw speckle patterns without intermediate image retrieval.By leveraging inherent features within speckles to extract discriminative features,our approach achieves nearly 90%accuracy for classifying speckles encoded with different images,outperforming traditional retrieval-classification pipelines by up to five times,even with extreme information sparsity(i.e.,1/1024 speckle regions of interest).In addition,we quantify speckle information capacity via information entropy analysis,demonstrating that classification accuracy correlates strongly with the information entropy of speckle autocorrelation.We not only overcome limitations of conventional methods but also establish a paradigm for real-time classification in scattering environments with constrained data.
基金supported by the National Natural Science Foundation of China(Nos.81671726 and 81627805)the Hong Kong Research Grant Council(No.25204416)+1 种基金the Shenzhen Science and Technology Innovation Commission(No.JCYJ20170818104421564)the Hong Kong Innovation and Technology Commission(No.ITS/022/18).
文摘Coherent optical control within or through scattering media via wavefront shaping has seen broad applications since its invention around 2007.Wavefront shaping is aimed at overcoming the strong scattering,featured by random interference,namely speckle patterns.This randomness occurs due to the refractive index inhomogeneity in complex media like biological tissue or the modal dispersion in multimode fiber,yet this randomness is actually deterministic and potentially can be time reversal or precompensated.Various wavefront shaping approaches,such as optical phase conjugation,iterative optimization,and transmission matrix measurement,have been developed to generate tight and intense optical delivery or high-resolution image of an optical object behind or within a scattering medium.The performance of these modula-tions,however,is far from satisfaction.Most recently,artifcial intelligence has brought new inspirations to this field,providing exciting hopes to tackle the challenges by mapping the input and output optical patterns and building a neuron network that inherently links them.In this paper,we survey the developments to date on this topic and briefly discuss our views on how to harness machine learning(deep learning in particular)for further advancements in the field.
基金supported by the Shenzhen Science and Technology Innovation Commission(No.JCYJ20170818104421564)the Hong Kong Innovation and Technology Commission(No.ITS/022/18)+1 种基金the Hong Kong Research Grant Council(No.25204416)the National Natural Science Foundation of China(Nos.81671726 and 81627805).
文摘Wavefront shaping(WFS)techniques have been used as a powerful tool to control light propagation in complex media,including multimode fibers.In this paper,we propose a new application of WFS for multimode fber-based sensors.The use of a single multimode fiber alone,without any special fabrication,as a sensor based on the light intensity variations is not an easy task.The twist effect on multimode fiber is used as an example herein.Experimental results show that light intensity through the multimode fiber shows no direct relationship with the twist angle,but the correlation coefficient(CC)of speckle patterns does.Moreover,if WFS is applied to transform the spatially seemingly random light pattern at the exit of the multimode fiber into an optical focus.The focal pattern correlation and intensity both can serve to gauge the twist angle,with doubled measurement range and allowance of using a fast point detector to provide the feedback.With further development,WFS may find potentials to facilitate the development of multimode fber-based sensors in a variety of scenarios.
文摘Photoacoustic(PA)imaging is a promising non-invasive and non-ionizing biomedical imaging modality that emerged in recent years.The articles presented in this special issue describe some of newest progress in this field.We are extremely grateful to all contributing authors.The first part of the issue covers new laser source devel-opment,including fiber lasers and laser diodes.The sec-ond part is dedicated to improving the image resolution through chronic cranial window techniques,virtual-point concept,fast polygon scanning,and Fabry Perot sensing.The third part shows the basic principles of photoacous-tic/ultrasound imaging and its applications.
基金financially supported by the National Key R&D Program of China(No.2018YFB1105700)the National Natural Science Foundation of China(Nos.81902913,81930048 and 81627805)+9 种基金the Guangdong Basic and Applied Basic Research Foundation for Distinguished Young Scholars(No.2020B1515020027)the Fundamental Research Funds for the Central Universities(No.19ykpy108)the Natural Science Foundation of Jiangsu Province(No.BK20190821)the Postdoctoral Science Foundation of China(No.2019M651953)the Open Project Program of the State Key Laboratory of Radiation Medicine and Protection,Soochow University(No.GZK1201909)the Guangdong Science and Technology Department(No.2020B1212060018)the Science and Technology Project from Suzhou City Commission of Health and Family Planning(No.LCZX201712)the grants from Guangzhou Science and Technology Bureau(202002020070,201902020015)Opening Foundation of Hubei Province Key Laboratory of Molecular Imaginga Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Multimodal imaging-guided chemo-photothermal therapy is an excellent cancer treatment,which can not only efficiently against tumor,but also can offer precise treatment window and real-time monitoring of the treatment efficiency.In our work,polydopamine(PDA)-coated gold nanobones(AuNBs@PDA nanocomplexes)were designed for this approach.The AuNBs@PDA nanocomplexes have strong absorbance in the near infrared(NIR)region and higher photothermal conversion efficiency(75.48%)than gold nanobones alone,which was facilitated for photoacoustic imaging and photothermal therapy.Besides,the loading efficiency of doxorubicin(DOX)by AuNBs@PDA nanocomplexes could be up to about 70%and DOX release from AuNBs@PDA/DOX nanocomplexes sensitively response to the lower pH environment and NIR laser irradiation,which makes them become the excellent nano-carrier for the delivery of chemotherapy drug.In vitro and in vivo studies showed significant cytotoxicity and antitumor efficacy by the AuNBs@PDA/DOX nanoplatform with negligible side effects.Meanwhile,the nanoplatform was also successfully employed for computed tomography(CT)imaging,attributing to the high atomic number and high X-ray attenuation coefficient of gold.Therefore,we believed that the proposed PDA-coated gold nanobones would be a novel multifunctional theranostic nanoagent to realize the PA/CT imaging-guided chemo-photothermal therapy of cancer.
基金National Natural Science Foundation of China(NSFC)(81671726,81930048,81627805,61675104)Hong Kong Research Grant Council(25204416)+2 种基金Hong Kong Innovation and Technology Commission(ITS/022/18)Guangdong Science and Technology Commission(2019A1515011374)Shenzhen Science Commission Innovation Technology and(JCYJ20170818104421564)
文摘Graphene derivatives,possessing strong Raman scattering and near-infrared absorption intrin-sically,have boosted many exciting biosensing applications.The tunability of the absorption characteristics,however,remains largely unexplored to date.Here,we proposed a multilayer configuration constructed by a graphene monolayer sandwiched between a buffer layer and one-dimensional photonic crystal(1DPC)to achieve tunable graphene absorption under total in-ternal reflection(TIR).It is interesting that the unique optical properties of the buffer-graphene-1DPC multilayer structure,the electromagnetically induced transparency(EIT)-like and Fano-like absorptions,can be achieved with pre-determined resonance wavelengths,and furtherly be tuned by adjusting either the structure parameters or the incident angle of light.Theoretical analyses demonstrate that such EIT-and Fano-like absorptions are due to the interference of light in the multilayer structure and the complete transmission produced by the evanescent wave resonance in the configuration.The enhanced absorptions and the huge electrical field en-hancement effect exhibit potentials for broad applications,such as photoacoustic imaging and Raman imaging.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant No.81930048)the Hong Kong Innovation and Technology Commission(Grant Nos.GHP/043/19SZ and GHP/044/19GD)+3 种基金the Hong Kong Research Grant Council(Grant Nos.15217721,R5029-19 and C7074-21GF)the Guangdong Science and Technology Commission(Grant No.2019BT02X105)the Shenzhen Science and Technology Innovation Commission(Grant No.JCYJ20220818100202005)the Hong Kong Polytechnic University(Grant Nos.P0038180,P0039517,P0043485 and P0045762).
文摘Transmission matrix(TM)allows light control through complex media,such as multimode fibers(MMFs),gaining great attention in areas,such as biophotonics,over the past decade.Efforts have been taken to retrieve a complex-valued TM directly from intensity measurements with several representative phase-retrieval algorithms,which still see limitations of slow or suboptimum recovery,especially under noisy environments.Here,we propose a modified nonconvex optimization approach.Through numerical evaluations,it shows that the optimum focusing efficiency is approached with less running time or sampling ratio.The comparative tests under different signal-to-noise levels further indicate its improved robustness.Experimentally,the superior focusing performance of our algorithm is collectively validated by single-and multispot focusing;especially with a sampling ratio of 8,it achieves a 93.6%efficiency of the gold-standard holography method.Based on the recovered TM,image transmission through an MMF is realized with high fidelity.Due to parallel operation and GPU acceleration,our nonconvex approach retrieves a 8685×1024 TM(sampling ratio is 8)with 42.3 s on average on a regular computer.The proposed method provides optimum efficiency and fast execution for TM retrieval that avoids the need for an external reference beam,which will facilitate applications of deep-tissue optical imaging,manipulation,and treatment.
文摘Optical technologies have been increasingly utilized in biomedicine,including diagnosis,therapy,and surgery.In almost all of these applications,photons need to propagate some distance in tissue.Therefore,the capability of focusing or demodulating light information plays an essential role,largely determining the sensitivity and spatial resolution of these techniques.This has always been desired yet considered challenging within or through thick biological tissues due to the strong scattering of light.
基金partially supported by the National Natural Science Foundation of China(Nos.11804120,61827822,and 22275072)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030209)+1 种基金Research Projects from Guangzhou(Nos.2023A03J0018 and 2024A04J3712)Fundamental Research Funds for the Central Universities(No.21623412).
文摘Fiber-structured ion sensors have gained traction in health monitoring and medical diagnostics owing to their structural flexibility,enhanced sensitivity,and suitability for integration into wearable devices.This study employed a simple and efficient solutionbased process to fabricate nanofibers containing aggregation-induced emission(AIE)dyes.The resulting AIE nanofibers exhibited stable and intense fluorescence,nanosecond fluorescence lifetime,and low-loss light transport when functioning as active waveguides.Additionally,crossed nanofiber intersections exhibited diffraction-limited emission spots.The AIE nanofibers demonstrate efficient and ionspecific fluorescence quenching in response to Ag^(+).These results support the development of sensing units capable of operating in liquid environments or in direct contact with skin or tissues,facilitating real-time monitoring of ion concentrations for personalized healthcare management.
基金supported by the National Key Research and Development Program of China(2022YFB4700100)the National Natural Science Foundation of China(T2225003,52073060,81930048,82330061,and 61927805)+4 种基金the Nanjing Medical Science and Tech-nique Development Foundation(ZKX21019)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02X105)the Hong Kong Research Grant Council General Research Fund(15217721 and 15125724)the Shenzhen Science and Technology Innovation Commission(JCYJ20220818100202005)the Hong Kong PolytechnicUniversity Fund(P0045680,P0043485,P0045762,and P0049101)。
文摘Flexible electronic skins hold great promise for biomedical applications,although challenges remain in achieving controllable interactions with the biological interface and accurate signal collection.Inspired by octopuses and chameleons,we propose a novel electronic skin paradigm with on-demand adhesion and opto-electronic synergistic display capabilities.Our electronic skins are composed of a stretchable polyurethane(PU)inverse opal film integrated with a carbon nanotube(CNT)-hybridized polyacrylamide(PAAm)-gelatin double-network-hydrogel conductive flexible substrate and a temperature-responsive poly(N-isopropylacrylamide)(PNIPAm)octopus-inspired hemispherical adhesive array.The device’s CNT hybrid double-network provides robust and sensitive monitoring of temperature and motion.Meanwhile,its flexible PU layer with an inverse opal structure allows for visual motion color sensing.Integrated neural network processing ensures accurate,wide-range,and independent multimodal display.Additionally,the integration of the photothermal effect of CNTs and the temperaturesensitive octopus-inspired PNIPAm adhesive array enables on-demand adhesion.The sensing and adhesion demonstrations ex vivo and in vivo showcase the proposed flexible electronic skin’s inspirational design and functional utilities.The potential applications of such a versatile device are vast,ranging from healthcare to human-machine interactions.
基金The National Natural Science Foundation of China(52403189)the Natural Science Foundation of Jiangsu Province(BK20220170)+1 种基金Shenzhen Second People’s Hospital Clinical Research Fund of Shenzhen High-level Hospital Construction Project(Grant No.20243357016)the Wenzhou Institute UCAS startup fund(WIUCASQD2024009).
文摘Biomedical patches have demonstrated value in promoting soft tissue repair or anti-adhesion.Research tendency in this area focuses on developing more controllable patches to meet the complex clinical scenarios.Herein,inspired by the controllable adhesion of suction cups and the antifouling properties of eyeball surfaces,we propose an anisotropic patch with‘revocable’adhesion mechanisms.For the adhesive-side,the initial adhesion forces mainly rely on suction cup’s physical interactions to allow adequate position adjustment,followed by the reaction of N-hydroxysuccinimide ester group with the tissue for firm covalent bonding.This multi-adhesive mechanism enables the spatiotemporal control of adhesive behavior.In contrast,on the barrier-side,the highly hydrated surface derived from polyethylene glycol and polyvinyl alcohol hydrogels displays no affinity for tissue proteins,thus effectively preventing tissue adhesion.Moreover,the intrinsic pores and charges enable the adsorption of positively charged inflammatory factors,while the loaded drugs can release sustainably.In vivo experiments demonstrate the patch’s strong yet controllable adhesion,effective in reducing inflammation and promoting healing.This innovative design introduces a new paradigm of‘revocable’adhesion,offering significant clinical potential for soft tissue repair and adhesion prevention.
基金Agency for Science,Technology and Research(A18A7b0058)National Natural Science Foundation of China(81627805,81671726,81930048)+3 种基金Guangdong Science and Technology Commission(2019A1515011374,2019BT02X105)Hong Kong Innovation and Technology Commission(GHP/043/19SZ,GHP/044/19GD,ITS/022/18)Hong Kong Research Grant Council(25204416,R5029-19)Shenzhen Science and Technology Innovation Commission(JCYJ20170818104421564)。
文摘Optical focusing through scattering media is of great significance yet challenging in lots of scenarios,including biomedical imaging,optical communication,cybersecurity,three-dimensional displays,etc.Wavefront shaping is a promising approach to solve this problem,but most implementations thus far have only dealt with static media,which,however,deviates from realistic applications.Herein,we put forward a deep learning-empowered adaptive framework,which is specifically implemented by a proposed Timely-Focusing-Optical-Transformation-Net(TFOTNet),and it effectively tackles the grand challenge of real-time light focusing and refocusing through time-variant media without complicated computation.The introduction of recursive fine-tuning allows timely focusing recovery,and the adaptive adjustment of hyperparameters of TFOTNet on the basis of medium changing speed efficiently handles the spatiotemporal non-stationarity of the medium.Simulation and experimental results demonstrate that the adaptive recursive algorithm with the proposed network significantly improves light focusing and tracking performance over traditional methods,permitting rapid recovery of an optical focus from degradation.It is believed that the proposed deep learning-empowered framework delivers a promising platform towards smart optical focusing implementations requiring dynamic wavefront control.
基金National Key Research and Development Program of China(2017YFA0700401)National Natural Science Foundation of China(81627805,81671726,81827808,81930048)+4 种基金Research Grants Council,University Grants Committee(25204416)Innovation and Technology Commission(GHP/043/19SZ,GHP/044/19GD,ITS/022/18)Guangdong Science and Technology Department(2019A1515011374,2019BT02X105)Science,Technology and Innovation Commission of Shenzhen Municipality(JCYJ20170818104421564)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2018167)。
文摘Optical imaging through or inside scattering media, such as multimode fiber and biological tissues, has a significant impact in biomedicine yet is considered challenging due to the strong scattering nature of light. In the past decade, promising progress has been made in the field, largely benefiting from the invention of iterative optical wavefront shaping, with which deep-tissue high-resolution optical focusing and hence imaging becomes possible. Most of the reported iterative algorithms can overcome small perturbations on the noise level but fail to effectively adapt beyond the noise level, e.g., sudden strong perturbations. Reoptimizations are usually needed for significant decorrelation to the medium since these algorithms heavily rely on the optimization performance in the previous iterations. Such ineffectiveness is probably due to the absence of a metric that can gauge the deviation of the instant wavefront from the optimum compensation based on the concurrently measured optical focusing.In this study, a square rule of binary-amplitude modulation, directly relating the measured focusing performance with the error in the optimized wavefront, is theoretically proved and experimentally validated. With this simple rule, it is feasible to quantify how many pixels on the spatial light modulator incorrectly modulate the wavefront for the instant status of the medium or the whole system. As an example of application, we propose a novel algorithm, the dynamic mutation algorithm, which has high adaptability against perturbations by probing how far the optimization has gone toward the theoretically optimal performance. The diminished focus of scattered light can be effectively recovered when perturbations to the medium cause a significant drop in the focusing performance, which no existing algorithms can achieve due to their inherent strong dependence on previous optimizations. With further improvement, the square rule and the new algorithm may boost or inspire many applications, such as high-resolution optical imaging and stimulation, in instable or dynamic scattering environments.
基金supported by National Natural Science Foundation of China(NSFC)(81930048,81627805)Hong Kong Research Grant Council(15217721,R5029-19,C7074-21GF)+3 种基金Hong Kong Innovation and Technology Commission(GHP/043/19SZ,GHP/044/19GD)Guangdong Science and Technology Commission(2019A1515011374,2019BT02X105)National Research Foundation of Korea(2015R1A3A2066550,2021R1A2C3012903)Institute of Information&Communications Technology Planning&Evaluation(IITP,2021-0-00745)grant funded by the Korea government(MSIT).
文摘Optical techniques offer a wide variety of applications as light-matter interactions provide extremely sensitive mechanisms to probe or treat target media.Most of these implementations rely on the usage of ballistic or quasi-ballistic photons to achieve high spatial resolution.However,the inherent scattering nature of light in biological tissues or tissue-like scattering media constitutes a critical obstacle that has restricted the penetration depth of non-scattered photons and hence limited the implementation of most optical techniques for wider applications.In addition,the components of an optical system are usually designed and manufactured for a fixed function or performance.Recent advances in wavefront shaping have demonstrated that scattering-or component-induced phase distortions can be compensated by optimizing the wavefront of the input light pattern through iteration or by conjugating the transmission matrix of the scattering medium.
基金Agency for Science,Technology and Research(A18A7b0058)Innovation and Technology Commission(GHP/043/19SZ,GHP/044/19GD)+2 种基金Hong Kong Research Grant Council(15217721,C5078-21EF,R5029-19)Guangdong Science and Technology Department(2019A1515011374,2019BT02X105)National Natural Science Foundation of China(81627805,81930048)。
文摘Information retrieval from visually random optical speckle patterns is desired in many scenarios yet considered challenging.It requires accurate understanding or mapping of the multiple scattering process,or reliable capability to reverse or compensate for the scattering-induced phase distortions.In whatever situation,effective resolving and digitization of speckle patterns are necessary.Nevertheless,on some occasions,to increase the acquisition speed and/or signal-to-noise ratio(SNR),speckles captured by cameras are inevitably sampled in the sub-Nyquist domain via pixel binning(one camera pixel contains multiple speckle grains)due to finite size or limited bandwidth of photosensors.Such a down-sampling process is irreversible;it undermines the fine structures of speckle grains and hence the encoded information,preventing successful information extraction.To retrace the lost information,super-resolution interpolation for such sub-Nyquist sampled speckles is needed.In this work,a deep neural network,namely SpkSRNet,is proposed to effectively up sample speckles that are sampled below 1/10 of the Nyquist criterion to well-resolved ones that not only resemble the comprehensive morphology of original speckles(decompose multiple speckle grains from one camera pixel)but also recover the lost complex information(human face in this study)with high fidelity under normal-and low-light conditions,which is impossible with classic interpolation methods.These successful speckle super-resolution interpolation demonstrations are essentially enabled by the strong implicit correlation among speckle grains,which is non-quantifiable but could be discovered by the well-trained network.With further engineering,the proposed learning platform may benefit many scenarios that are physically inaccessible,enabling fast acquisition of speckles with sufficient SNR and opening up new avenues for seeing big and seeing clearly simultaneously in complex scenarios.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFC0100602)National Natural Science Foundation of China(Grant Nos.81930048,81671726,and 81627805)+2 种基金Guangdong Science and Technology Commission(Grant Nos.2019BT02X105,and 2019A1515011374)Hong Kong Research Grant Council(Grant Nos.15217721,R5029-19,and C7074-21GF)Hong Kong Innovation and Technology Commission(Grant Nos.GHP/043/19SZ and GHP/044/19GD).
文摘High-resolution optical imaging through or within thick scattering media is a long sought after yet unreached goal.In the past decade,the thriving technique developments in wavefront measurement and manipulation do not significantly push the boundary forward.The optical diffusion limit is still a ceiling.In this work,we propose that a scattering medium can be conceptualized as an assembly of randomly packed pinhole cameras and the corresponding speckle pattern as a superposition of randomly shifted pinhole images.The concept is demonstrated through both simulation and experiments,confirming the new perspective to interpret the mechanism of information transmission through scattering media under incoherent illumination.We also analyze the efficiency of single-pinhole and dual-pinhole channels.While in infancy,the proposed method reveals a new perspective to understand imaging and information transmission through scattering media.
基金National Natural Science Foundation of China(81930048)Guangdong Science and Technology Department(2019BT02X105)+2 种基金Research Grants Council,University Grants Committee(15217721,C7074-21GF,R5029-19)Innovation and Technology Commission(GHP/043/19SZ,GHP/044/19GD)Hong Kong Polytechnic University(P0038180,P0039517,P0043485)。
文摘Imaging through scattering media is valuable for many areas,such as biomedicine and communication.Recent progress enabled by deep learning(DL)has shown superiority especially in the model generalization.However,there is a lack of research to physically reveal the origin or define the boundary for such model scalability,which is important for utilizing DL approaches for scalable imaging despite scattering with high confidence.In this paper,we find the amount of the ballistic light component in the output field is the prerequisite for endowing a DL model with generalization capability by using a“one-to-all”training strategy,which offers a physical meaning invariance among the multisource data.The findings are supported by both experimental and simulated tests in which the roles of scattered and ballistic components are revealed in contributing to the origin and physical boundary of the model scalability.Experimentally,the generalization performance of the network is enhanced by increasing the portion of ballistic photons in detection.The mechanism understanding and practical guidance by our research are beneficial for developing DL methods for descattering with high adaptivity.
文摘Time-gated reflection matrix(RM)has been successfully used for optical imaging deep inside Scattering media.Recently,this method was extended to enhance the spatiotemporal focusing of light ultra-deep inside scattering media.This is achieved by calibrating the decomposition of the RM with the Tikhonov regularization parameter to convert mutiply scattered photons that share the same time of flight with the singly scattered photons into singly scattered photons.Such a capability suggests a reshaping to the interaction mechanism between light and scattering media,which may beneft or inspire wide optical applications that desire enhanced spatiotemporal focusing of light at depths inside scattering media.
基金The Hong Kong Polytechnic University(P0038180,P0039517,P0043485,P0045762)Shenzhen Science and Technology Innovation Program(JCYJ20220818100202005)+3 种基金Guangdong Science and Technology Department(2019BT02X105)Hong Kong Research Grant Council(15217721,C7074-21GF,R5029-19)Innovation and Technology Commission(GHP/043/19SZ,GHP/044/19GD)National Natural Science Foundation of China(81930048)。
文摘Multimode fibers(MMFs)are a promising solution for high-throughput signal transmission in the time domain.However,crosstalk among different optical modes within the MMF scrambles input information and creates seemingly random speckle patterns at the output.To characterize this process,a transmission matrix(TM)can be used to relate input and output fields.Recent innovations use TMs to manipulate the output field by shaping the input wavefront for exciting advances in deep-brain imaging,neuron stimulation,quantum networks,and analog operators.However,these approaches consider input/output segments as independent,limiting their use for separate signal processing,such as logic operations.Our proposed method,which makes input/output segments as interdependent,adjusts the phase of corresponding output fields using phase bias maps superimposed on input segments.Coherent superposition enables signal logic operations through a 15-m-long MMF.In experiments,a single optical logic gate containing three basic logic functions and cascading multiple logic gates to handle binary operands is demonstrated.Bitwise operations are performed for multi-bit logic operations,and multiple optical logic gates are reconstructed simultaneously in a single logic gate with polarization multiplexing.The proposed method may open new avenues for long-range logic signal processing and transmission via MMFs.
基金This work was supported in part by the National Natural Science Foundation of China(NSFC)(Grant Nos.8193004&81627805,and 81671726)Guangdong Science and Technology Commission(Nos.2019BT02X105,2019A1515011374)+4 种基金Hong Kong Research Grant Council(Nos.25204416,R5029-19)Hong Kong Innovation and Technology Commission(Nos.ITS/022/18,GHP/043/19SZ,GHP/044/19GD)Shenzhen Science and Technology Innovation Commission(No.JCYJ20170818104421564)Guangdong Basic and Applied Basic Research Foundation for Distinguished Young Scholars(No.2020B1515020027)Guangzhou Science and Technology Bureau(No.202002020070).
文摘As an outstanding two-dimensional material,black phosphorene,has attracted significant attention in the biomedicine field due to its large surface area,strong optical absorption,distinct bioactivity,excellent biocompatibility,and high biodegradability.In this review,the preparation and properties of black phosphorene are summarized first.Thereafter,black phosphorene-based multifunctional platforms employed for the diagnosis and treatment of diseases,including cancer,bone injuries,brain diseases,progressive oxidative diseases,and kidney injury,are reviewed in detail.This review provides a better understanding of the exciting properties of black phosphorene,such as its high drug-loading efficiency,photothermal conversion capability,high'O2 generation efficiency,and high electrical conductivity,as well as how these properties can be exploited in biomedicine.Finally,the research perspectives of black phosphorene are discussed.
