We show how to design an optical device that can perform any linear function or coupling between inputs and outputs.This design method is progressive,requiring no global optimization.We also show how the device can co...We show how to design an optical device that can perform any linear function or coupling between inputs and outputs.This design method is progressive,requiring no global optimization.We also show how the device can configure itself progressively,avoiding design calculations and allowing the device to stabilize itself against drifts in component properties and to continually adjust itself to changing conditions.This self-configuration operates by training with the desired pairs of orthogonal input and output functions,using sets of detectors and local feedback loops to set individual optical elements within the device,with no global feedback or multiparameter optimization required.Simple mappings,such as spatial mode conversions and polarization control,can be implemented using standard planar integrated optics.In the spirit of a universal machine,we show that other linear operations,including frequency and time mappings,as well as nonreciprocal operation,are possible in principle,even if very challenging in practice,thus proving there is at least one constructive design for any conceivable linear optical component;such a universal device can also be self-configuring.This approach is general for linear waves,and could be applied to microwaves,acoustics,and quantum mechanical superpositions.展开更多
Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially wit...Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that such beams can be still separated in the optical domain, and simultaneously detected with negligible cross-talk, even if they share the same wavelength and polarization, and even with unknown arriving beam shapes. The kernel of the adaptive multibeam receiver presented in this work is a programmable integrated photonic processor that is coupled to free-space beams through a two-dimensional array of optical antennas. We demonstrate separation of beam pairs arriving from different directions, with overlapping spatial modes in the same direction, and even with mixing between the beams deliberately added in the path. With the circuit’s optical bandwidth of more than 40 nm, this approach offers an enabling technology for the evolution of FSO from single-beam to multibeam space-division multiplexed systems in a perturbed environment, which has been a game-changing transition in fiber-optic systems.展开更多
In technologies operating at light wavelengths for wireless communication,sensor networks,positioning,and ranging,a dynamic coherent control and manipulation of light fields is an enabling element for properly generat...In technologies operating at light wavelengths for wireless communication,sensor networks,positioning,and ranging,a dynamic coherent control and manipulation of light fields is an enabling element for properly generating and correctly receiving free-space optical(FSO)beams even in the presence of unpredictable objects and turbulence in the light path.In this work,we use a programmable mesh of Mach-Zehnder(MZI)interferometers to automatically control the complex field radiated and captured by an array of optical antennas.The implementation of local feedback control loops in each MZI stage,without global multivariable optimization techniques,enables an unlimited scalability.Several functionalities are demonstrated,including the generation of perfectly shaped beams with nonperfect optical antennas,the imaging of a desired field pattern through an obstacle or a diffusive medium,and the identification of an unknown obstacle inserted in the FSO path.Compared to conventional devices used for the manipulation of FSO beams,such as spatial light modulators,our programmable device can self-configure through automated control strategies and can be integrated with other functionalities implemented onto the same photonic chip.展开更多
In Sub-Saharan Africa, cholera is a persistent public health problem. Various methods are now being applied to reduce the mobility and mortality that these diseases cause. Because of the implemented policies, there se...In Sub-Saharan Africa, cholera is a persistent public health problem. Various methods are now being applied to reduce the mobility and mortality that these diseases cause. Because of the implemented policies, there seem to have been several improvements. However, the constraints suggest inefficiency in eliminating the burden, necessitating a straightforward explanation. The systematic review and meta-analysis aimed are to investigate the reasons for the incomplete eradication of cholera disease in Sub-Saharan Africa. We were able to obtain pooled estimates using random effect models. Four experiments were excluded from the study because they were duplicated in the studies, 13 because of an outbreak did not occur, 13 publications did not include risk factors and odds ratios in their outcome analysis, and an outbreak occurred before 2013. The review points out that drinking contaminated water, consuming unwashed vegetables, and the use of poor publish toilet facilities enhance cholera in Africa. PubMed, Web of Science, EMBASE, and EBSCO were among the four meticulously and systematically searched databases using predetermined criteria or search strategies. Two independent reviewers recognized studies that met the selection criteria, and data was collected using validated methods.展开更多
In recent years, superhydrophobic media has attracted tremendous attention due to its industrial applicability value, especially in anti-corrosion performance. The superhydrophobic coating, which has a robust and wate...In recent years, superhydrophobic media has attracted tremendous attention due to its industrial applicability value, especially in anti-corrosion performance. The superhydrophobic coating, which has a robust and water-repellent capacity, can catch the air to form several “airbags” on the substrate’s surface, isolating the corrosion media. Various superhydrophobic coating preparation technologies have been suggested, but each has its own set of flaws. On the other hand, electrodeposition, as a relatively mature industrial processing application, offers distinct advantages. However, until now, there have been few reviews on the electrodeposition preparation of anticorrosive superhydrophobic coatings. Therefore, the author has described several fabrication techniques based on superhydrophobic coatings in this review, including the advantages and disadvantages. Superhydrophobic coatings conventional concepts and wettability, as well as the model wetting concepts, have been reviewed. The coating processing status and the corrosion-resistant potential through the electrodeposition of metal and comparable composite are detailly encapsulated. Furthermore, electrodeposition parameters, including current density, crystal modifiers, and a deposition time of the coating morphology, are reported, following the ultrasonic-assisted, jet, pulse, and magnetic field-induced electrodeposition, respectively, as the recently developed technologies for preparing a coating. Finally, technology limitation is shown as well as the obstacles and prospects, and the improvement of the superhydrophobic coating’s durability as a prospects research focus has been recommended.展开更多
基金funds from Duke University under an award from the DARPA InPho program,and by Multidisciplinary University Research Initiative grants(Air Force Office of Scientific Research,FA9550-10-1-0264 and FA9550-09-0704).
文摘We show how to design an optical device that can perform any linear function or coupling between inputs and outputs.This design method is progressive,requiring no global optimization.We also show how the device can configure itself progressively,avoiding design calculations and allowing the device to stabilize itself against drifts in component properties and to continually adjust itself to changing conditions.This self-configuration operates by training with the desired pairs of orthogonal input and output functions,using sets of detectors and local feedback loops to set individual optical elements within the device,with no global feedback or multiparameter optimization required.Simple mappings,such as spatial mode conversions and polarization control,can be implemented using standard planar integrated optics.In the spirit of a universal machine,we show that other linear operations,including frequency and time mappings,as well as nonreciprocal operation,are possible in principle,even if very challenging in practice,thus proving there is at least one constructive design for any conceivable linear optical component;such a universal device can also be self-configuring.This approach is general for linear waves,and could be applied to microwaves,acoustics,and quantum mechanical superpositions.
基金the European Commission,Horizon 2020 Programme(SuperPixels,grant no.829116)by the Air Force Office of Scientific Research(AFOSR,grant no.FA9550-17-1-0002).
文摘Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that such beams can be still separated in the optical domain, and simultaneously detected with negligible cross-talk, even if they share the same wavelength and polarization, and even with unknown arriving beam shapes. The kernel of the adaptive multibeam receiver presented in this work is a programmable integrated photonic processor that is coupled to free-space beams through a two-dimensional array of optical antennas. We demonstrate separation of beam pairs arriving from different directions, with overlapping spatial modes in the same direction, and even with mixing between the beams deliberately added in the path. With the circuit’s optical bandwidth of more than 40 nm, this approach offers an enabling technology for the evolution of FSO from single-beam to multibeam space-division multiplexed systems in a perturbed environment, which has been a game-changing transition in fiber-optic systems.
基金H2020 Future and Emerging Technologies(829116)Air Force Office of Scientific Research(FA9550-17-1-000)。
文摘In technologies operating at light wavelengths for wireless communication,sensor networks,positioning,and ranging,a dynamic coherent control and manipulation of light fields is an enabling element for properly generating and correctly receiving free-space optical(FSO)beams even in the presence of unpredictable objects and turbulence in the light path.In this work,we use a programmable mesh of Mach-Zehnder(MZI)interferometers to automatically control the complex field radiated and captured by an array of optical antennas.The implementation of local feedback control loops in each MZI stage,without global multivariable optimization techniques,enables an unlimited scalability.Several functionalities are demonstrated,including the generation of perfectly shaped beams with nonperfect optical antennas,the imaging of a desired field pattern through an obstacle or a diffusive medium,and the identification of an unknown obstacle inserted in the FSO path.Compared to conventional devices used for the manipulation of FSO beams,such as spatial light modulators,our programmable device can self-configure through automated control strategies and can be integrated with other functionalities implemented onto the same photonic chip.
文摘In Sub-Saharan Africa, cholera is a persistent public health problem. Various methods are now being applied to reduce the mobility and mortality that these diseases cause. Because of the implemented policies, there seem to have been several improvements. However, the constraints suggest inefficiency in eliminating the burden, necessitating a straightforward explanation. The systematic review and meta-analysis aimed are to investigate the reasons for the incomplete eradication of cholera disease in Sub-Saharan Africa. We were able to obtain pooled estimates using random effect models. Four experiments were excluded from the study because they were duplicated in the studies, 13 because of an outbreak did not occur, 13 publications did not include risk factors and odds ratios in their outcome analysis, and an outbreak occurred before 2013. The review points out that drinking contaminated water, consuming unwashed vegetables, and the use of poor publish toilet facilities enhance cholera in Africa. PubMed, Web of Science, EMBASE, and EBSCO were among the four meticulously and systematically searched databases using predetermined criteria or search strategies. Two independent reviewers recognized studies that met the selection criteria, and data was collected using validated methods.
文摘In recent years, superhydrophobic media has attracted tremendous attention due to its industrial applicability value, especially in anti-corrosion performance. The superhydrophobic coating, which has a robust and water-repellent capacity, can catch the air to form several “airbags” on the substrate’s surface, isolating the corrosion media. Various superhydrophobic coating preparation technologies have been suggested, but each has its own set of flaws. On the other hand, electrodeposition, as a relatively mature industrial processing application, offers distinct advantages. However, until now, there have been few reviews on the electrodeposition preparation of anticorrosive superhydrophobic coatings. Therefore, the author has described several fabrication techniques based on superhydrophobic coatings in this review, including the advantages and disadvantages. Superhydrophobic coatings conventional concepts and wettability, as well as the model wetting concepts, have been reviewed. The coating processing status and the corrosion-resistant potential through the electrodeposition of metal and comparable composite are detailly encapsulated. Furthermore, electrodeposition parameters, including current density, crystal modifiers, and a deposition time of the coating morphology, are reported, following the ultrasonic-assisted, jet, pulse, and magnetic field-induced electrodeposition, respectively, as the recently developed technologies for preparing a coating. Finally, technology limitation is shown as well as the obstacles and prospects, and the improvement of the superhydrophobic coating’s durability as a prospects research focus has been recommended.
