We propose a new algorithm for wavefront sensing based on binary intensity modulation. The algorithm is based on the fact that a wavefront can be expended with a series of orthogonal and binary functions, the Walsh se...We propose a new algorithm for wavefront sensing based on binary intensity modulation. The algorithm is based on the fact that a wavefront can be expended with a series of orthogonal and binary functions, the Walsh series. We use a spatial light modulator（SLM） to produce different binary-intensity-modulation patterns which are the simple linear transformation of the Walsh series. The optical fields under different binary-intensity-modulation patterns are detected with a photodiode.The relationships between the incident wavefront modulated with the patterns and their optical fields are built to determinate the coefficients of the Walsh series. More detailed and strict relationship equations are established with the algorithm by adding new modulation patterns according to the properties of the Walsh functions. An exact value can be acquired by solving the equations. Finally, with the help of phase unwrapping and smoothing, the wavefront can be reconstructed. The advantage of the algorithm is providing an analytical solution for the coefficients of the Walsh series to reconstruct the wavefront. The simulation experiments are presented and the effectiveness of the algorithm is demonstrated.展开更多
Based on the angular spectrum method and the circular Gaussian distribution(CGD) model of scattering media,we numerically simulate light focusing through strongly scattering media.A high contrast focus in the target a...Based on the angular spectrum method and the circular Gaussian distribution(CGD) model of scattering media,we numerically simulate light focusing through strongly scattering media.A high contrast focus in the target area is produced by using feedback optimization algorithm with binary amplitude modulation.It is possible to form the focusing with one focus or multiple foci at arbitrary areas.The influence of the number of square segments of spatial light modulation on the enhancement factor of intensity is discussed.Simulation results are found to be in good agreement with theoretical analysis for light refocusing.展开更多
In this paper, we study the propagation of the pattern for a reaction-diffusionchemotaxis model. By using a weakly nonlinear analysis with multiple temporal and spatial scales, we establish the amplitude equations for...In this paper, we study the propagation of the pattern for a reaction-diffusionchemotaxis model. By using a weakly nonlinear analysis with multiple temporal and spatial scales, we establish the amplitude equations for the patterns, which show that a local perturbation at the constant steady state is spread over the whole domain in the form of a traveling wavefront. The simulations demonstrate that the amplitude equations capture the evolution of the exact patterns obtained by numerically solving the considered system.展开更多
Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbi...Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum(OAM).Here we have reviewed the ways to generate THz vortex beams by two representative scenarios,i.e.,THz wavefront modulation via specific devices,and direct excitation of the helicity of THz vortex beams.The former is similar to those wavefront engineering devices in the optical and infrared(IR)domain,but just with suitable THz materials,while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though,which would provide both challenges and opportunities for THz vortex beam generation.As for their applications,thanks to the recent development of THz optics and singular optics,THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields.Besides,some representative potential applications are evaluated such as THz wireless communication,THz super-resolution imaging,manipulating chiral matters,accelerating electron bunches,and detecting astrophysical sources.展开更多
A tunable plasmofluidic lens consisting of nanoslit arrays on a metal film is proposed for subwavelength imaging in far field at different wavelengths.The nanoslit arrays with constant depths but varying widths could ...A tunable plasmofluidic lens consisting of nanoslit arrays on a metal film is proposed for subwavelength imaging in far field at different wavelengths.The nanoslit arrays with constant depths but varying widths could generate desired optical phase retardations based on the propagation property of the surface plasmon polaritons(SPPs)through the metal-dielectric-metal(MDM)nanoslit waveguide.We demonstrate the tunability of the plasmofluidic lens for subwavelength imaging by changing the surrounding dielectric fluid.This work provides a novel approach for developing integrative tunable plasmofluidic lens for a variety of lab-on-chip applications.展开更多
A new method is presented to display ultrasonic traveling wavefront by colltinuously modulated laser diode based on the temporal correlation theory. It is proved by experimeot.
Holography has attracted tremendous interest due to its capability of storing boththe amplitude and phase of light field and reproducing vivid three-dimensionalscenes. However, the large pixel size, low resolution, sm...Holography has attracted tremendous interest due to its capability of storing boththe amplitude and phase of light field and reproducing vivid three-dimensionalscenes. However, the large pixel size, low resolution, small field-of-view (FOV) andlimited space-bandwidth of traditional spatial light modulator (SLM) devices restrictthe possibility of improving the quality of reconstructed images. With thedevelopment of nanofabrication technologies, metasurfaces have shown greatpotential in manipulating the amplitude, phase, polarization, frequency orsimultaneously multiple parameters of output light in ultrashort distance withsubwavelength resolution by tailoring the scattering behaviour of consistednanostructures. Such flexibilities make metasurface a promising candidate forholographic related applications. Here, we review recent progresses in the field ofmetasurface holography. From the perspective of the fundamental properties oflight, we classify the metasurface holography into several categories such as phaseonlyholography, amplitude-only holography, complex amplitude holography and soon. Then, we introduce the corresponding working principles and design strategies.Meanwhile, some emerging types of metasurface holography such as tunableholography, nonlinear holography, Janus (or directional related) and bilayermetasurfaces holography are also discussed. At last, we make our outlook onmetasurface holography and discuss the challenges we may face in the future.展开更多
基金Project supported by the National Innovation Fund of Chinese Academy of Sciences(Grant No.CXJJ-16M208)the Preeminent Youth Fund of Sichuan Province,China(Grant No.2012JQ0012)the Outstanding Youth Science Fund of Chinese Academy of Sciences
文摘We propose a new algorithm for wavefront sensing based on binary intensity modulation. The algorithm is based on the fact that a wavefront can be expended with a series of orthogonal and binary functions, the Walsh series. We use a spatial light modulator（SLM） to produce different binary-intensity-modulation patterns which are the simple linear transformation of the Walsh series. The optical fields under different binary-intensity-modulation patterns are detected with a photodiode.The relationships between the incident wavefront modulated with the patterns and their optical fields are built to determinate the coefficients of the Walsh series. More detailed and strict relationship equations are established with the algorithm by adding new modulation patterns according to the properties of the Walsh functions. An exact value can be acquired by solving the equations. Finally, with the help of phase unwrapping and smoothing, the wavefront can be reconstructed. The advantage of the algorithm is providing an analytical solution for the coefficients of the Walsh series to reconstruct the wavefront. The simulation experiments are presented and the effectiveness of the algorithm is demonstrated.
基金supported by the National Natural Science Foundation of China(Nos.61178015 and 11304104)
文摘Based on the angular spectrum method and the circular Gaussian distribution(CGD) model of scattering media,we numerically simulate light focusing through strongly scattering media.A high contrast focus in the target area is produced by using feedback optimization algorithm with binary amplitude modulation.It is possible to form the focusing with one focus or multiple foci at arbitrary areas.The influence of the number of square segments of spatial light modulation on the enhancement factor of intensity is discussed.Simulation results are found to be in good agreement with theoretical analysis for light refocusing.
基金partially supported by the National Natural Science Foundation of China(11671359)the Provincial Natural Science Foundation of Zhejiang(LY15A010017,LY16A010009)the Science Foundation of Zhejiang Sci-Tech University 15062173-Y
文摘In this paper, we study the propagation of the pattern for a reaction-diffusionchemotaxis model. By using a weakly nonlinear analysis with multiple temporal and spatial scales, we establish the amplitude equations for the patterns, which show that a local perturbation at the constant steady state is spread over the whole domain in the form of a traveling wavefront. The simulations demonstrate that the amplitude equations capture the evolution of the exact patterns obtained by numerically solving the considered system.
基金Project supported partly by the National Natural Science Foundation of China(Grant Nos.61775142 and 61705132)Shenzhen Fundamental Research and Discipline Layout Project,China(Grant Nos.JCYJ20170412105812811,JCYJ20190808164007485,JCYJ20190808121817100,and JCYJ20190808115601653).
文摘Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum(OAM).Here we have reviewed the ways to generate THz vortex beams by two representative scenarios,i.e.,THz wavefront modulation via specific devices,and direct excitation of the helicity of THz vortex beams.The former is similar to those wavefront engineering devices in the optical and infrared(IR)domain,but just with suitable THz materials,while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though,which would provide both challenges and opportunities for THz vortex beam generation.As for their applications,thanks to the recent development of THz optics and singular optics,THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields.Besides,some representative potential applications are evaluated such as THz wireless communication,THz super-resolution imaging,manipulating chiral matters,accelerating electron bunches,and detecting astrophysical sources.
文摘A tunable plasmofluidic lens consisting of nanoslit arrays on a metal film is proposed for subwavelength imaging in far field at different wavelengths.The nanoslit arrays with constant depths but varying widths could generate desired optical phase retardations based on the propagation property of the surface plasmon polaritons(SPPs)through the metal-dielectric-metal(MDM)nanoslit waveguide.We demonstrate the tunability of the plasmofluidic lens for subwavelength imaging by changing the surrounding dielectric fluid.This work provides a novel approach for developing integrative tunable plasmofluidic lens for a variety of lab-on-chip applications.
文摘A new method is presented to display ultrasonic traveling wavefront by colltinuously modulated laser diode based on the temporal correlation theory. It is proved by experimeot.
基金National Key Research and Development Program of China 2017YFB1002900,Ministry of Science and Technology,ChinaFok Ying-Tong Education Foundation of China(161009)+3 种基金Beijing Nova Program(Z171100001117047)Natural Science Foundation of Beijing Municipality(4172057)National Natural Science Foundation of China(61775019)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910007022).
文摘Holography has attracted tremendous interest due to its capability of storing boththe amplitude and phase of light field and reproducing vivid three-dimensionalscenes. However, the large pixel size, low resolution, small field-of-view (FOV) andlimited space-bandwidth of traditional spatial light modulator (SLM) devices restrictthe possibility of improving the quality of reconstructed images. With thedevelopment of nanofabrication technologies, metasurfaces have shown greatpotential in manipulating the amplitude, phase, polarization, frequency orsimultaneously multiple parameters of output light in ultrashort distance withsubwavelength resolution by tailoring the scattering behaviour of consistednanostructures. Such flexibilities make metasurface a promising candidate forholographic related applications. Here, we review recent progresses in the field ofmetasurface holography. From the perspective of the fundamental properties oflight, we classify the metasurface holography into several categories such as phaseonlyholography, amplitude-only holography, complex amplitude holography and soon. Then, we introduce the corresponding working principles and design strategies.Meanwhile, some emerging types of metasurface holography such as tunableholography, nonlinear holography, Janus (or directional related) and bilayermetasurfaces holography are also discussed. At last, we make our outlook onmetasurface holography and discuss the challenges we may face in the future.
