The matrix eigenvalue method is used to analyze a laser resonator composed of diffraction optical elements. The results show that this type of resonator can separate fundamental mode and high order modes effectively. ...The matrix eigenvalue method is used to analyze a laser resonator composed of diffraction optical elements. The results show that this type of resonator can separate fundamental mode and high order modes effectively. The output beams can be designed for different requests.展开更多
Diffractive optical elements(DOEs) with spectrum separation and beam concentration(SSBC) functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into seve...Diffractive optical elements(DOEs) with spectrum separation and beam concentration(SSBC) functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.展开更多
In this paper,a novel method is proposed and employed to design a single diffractive optical element(DOE) for implementing spectrum-splitting and beam-concentration(SSBC) functions simultaneously.We develop an opt...In this paper,a novel method is proposed and employed to design a single diffractive optical element(DOE) for implementing spectrum-splitting and beam-concentration(SSBC) functions simultaneously.We develop an optimization algorithm,through which the SSBC DOE can be optimized within an arbitrary thickness range according to the limitations of modern photolithography technology.Theoretical simulation results reveal that the designed SSBC DOE has a high optical focusing efficiency.It is expected that the designed SSBC DOE should have practical applications in high-efficiency solar cell systems.展开更多
1 Introduction 1.1 Advantages of DOE 1)High diffraction efficiency; 2)Dispersive; 3)More selectivity of designing parameters; 4)More selectivity of primary materials; 5)Can make components miniature,forming array and ...1 Introduction 1.1 Advantages of DOE 1)High diffraction efficiency; 2)Dispersive; 3)More selectivity of designing parameters; 4)More selectivity of primary materials; 5)Can make components miniature,forming array and integration. 1.2 1.3 megapixel triplet plastic mobile展开更多
Based on the facts that multijunction solar cells can increase the efficiency and concentration can reduce the cost dramatically, a special design of parallel multijunction solar cells was presented. The design employ...Based on the facts that multijunction solar cells can increase the efficiency and concentration can reduce the cost dramatically, a special design of parallel multijunction solar cells was presented. The design employed a diffractive optical element (DOE) to split and concentrate the sunlight. A rainbow region and a zero-order diffraction region were generated on the output plane where solar cells with corresponding band gaps were placed. An analytical expression of the light intensity distribution on the output plane of the special DOE was deduced, and the limiting photovoltaic efficiency of such parallel multijunction solar ceils was obtained based on Shockley-Queisser's theory. An efficiency exceeding the Shockley--Queisser limit (33%) can be expected using multijunction solar cells consisting of separately fabricated subcells. The results provide an important alternative approach to realize high photovoltaic efficiency without the need for expensive epitaxial technology widely used in tandem solar cells, thus stimulating the research and application of high efficiency and low cost solar cells.展开更多
A spectrum-splitting and beam-concentrating (SSBC) diffractive optical element (DOE) for three-junction pho- tovoltaics (PV) system is designed and fabricated by five-circ/e micro-fabrication. The incident solar...A spectrum-splitting and beam-concentrating (SSBC) diffractive optical element (DOE) for three-junction pho- tovoltaics (PV) system is designed and fabricated by five-circ/e micro-fabrication. The incident solar light is efficiently split into three sub-spectrum ranges and strongly concentrated on the focal plane, which can be di- rectly utilized by suitable spectrum-matching solar cells. The system concentration factor reaches 12x. Moreover, the designed wavelengths (450nm, 550nm and 65Onto) are spatially distributed on the focal plane, in good agree- ment with the theoretical results. The average optical effic/ency of all the cells over the three designed wavelengths is 60.07%. The SSBC DOE with a high concentration factor and a high optical efficiency provides a cost-effective approach to achieve higher PV conversion efficieneies.展开更多
Two improved algorithms are proposed to extend a diffractive optical element (DOE) to work under the broad spec- trum of sunlight. An optimum design has been found for the DOE, with a weighted average optical effici...Two improved algorithms are proposed to extend a diffractive optical element (DOE) to work under the broad spec- trum of sunlight. An optimum design has been found for the DOE, with a weighted average optical efficiency of about 6.8% better than that of the previous design. The optimization of designing high optical efficiency DOEs will pave the way for future designs of high-efficiency, low-cost lateral multijunction solar cells based on such a DOE.展开更多
Diffractive optics is an important technique for beam shaping with high light efficiency and strong diffraction pattern flexibility. Since the diffraction angle is limited by the unit size of the diffractive optical e...Diffractive optics is an important technique for beam shaping with high light efficiency and strong diffraction pattern flexibility. Since the diffraction angle is limited by the unit size of the diffractive optical element (DOE), the size of the required diffraction pattern is always rather small. In this Letter, refractive/diffractive hybrid optical elements (RDHOEs) consisting of a DOE and a lens are used to realize beam shaping for a large diffraction pattern. The lens, as the component of the RDHOEs, can not only be concave but also convex, and the double sampling Fresnel diffraction algorithm is developed for the design of these two types of RDHOEs. The simulation and experimental results provide solid evidence to demonstrate the proposed method with the pure phase spatial light modulator.展开更多
Diffractive optical elements(DOEs)are intricately designed devices with the purpose of manipulating light fields by precisely modifying their wavefronts.The concept of DOEs has its origins dating back to 1948 when D.G...Diffractive optical elements(DOEs)are intricately designed devices with the purpose of manipulating light fields by precisely modifying their wavefronts.The concept of DOEs has its origins dating back to 1948 when D.Gabor first introduced holography.Subsequently,researchers introduced binary optical elements(BOEs),including computer-generated holograms(CGHs),as a distinct category within the realm of DOEs.This was the first revolution in optical devices.The next major breakthrough in light field manipulation occurred during the early 21st century,marked by the advent of metamaterials and metasurfaces.Metasurfaces are particularly appealing due to their ultra-thin,ultra-compact properties and their capacity to exert precise control over virtually every aspect of light fields,including amplitude,phase,polarization,wavelength/frequency,angular momentum,etc.The advancement of light field manipulation with micro/nano-structures has also enabled various applications in fields such as information acquisition,transmission,storage,processing,and display.In this review,we cover the fundamental science,cutting-edge technologies,and wide-ranging applications associated with micro/nano-scale optical devices for regulating light fields.We also delve into the prevailing challenges in the pursuit of developing viable technology for real-world applications.Furthermore,we offer insights into potential future research trends and directions within the realm of light field manipulation.展开更多
Annular-focused beams have attracted attention because of their novel properties and applications in optical trapping, high resolution microscopy, and laser-induced periodic surface structuring. Generation of this bea...Annular-focused beams have attracted attention because of their novel properties and applications in optical trapping, high resolution microscopy, and laser-induced periodic surface structuring. Generation of this beam is very important and necessary. In this article, a novel design of zone plate for forming the annular-focused beams is proposed. The design principle is introduced, and the characteristics of zone plate are analyzed by numerical simulation. The result shows that the zone plate can form a monochromatic ring-shaped intensity distribution in the focal plane. And the design method is also generally suitable for designing the other optical elements to generate the annular-focused beams.展开更多
Multifocal multiphoton microscopy(MMM)has recently become an important tool in biomedicine for performing three-dimensional fastfluorescence imaging.Using various beamsplitting techniques,MMM splits the near-infrared ...Multifocal multiphoton microscopy(MMM)has recently become an important tool in biomedicine for performing three-dimensional fastfluorescence imaging.Using various beamsplitting techniques,MMM splits the near-infrared laser beam into multiple beamlets and produces a multifocal array on the sample for parallel multiphoton excitation and then recordsfluorescence signal from all foci simultaneously with an area array detector,which significantly improves the imaging speed of multiphoton microscopy and allows for high efficiency in use of the excitation light.In this paper,we discuss the features of several MMM setups using different beamsplitting devices,including a Nipkow spinning disk,a microlens array,a set of beamsplitting mirrors,or a diffractive optical element(DOE).In particular,we present our recent work on the development of an MMM using a spatial light modulator(SLM).展开更多
Diffractive optical elements such as the complementary Dammann gratings are incorporated for dynamic optical fiber splitting and combining. Experimental results of 1×8 dynamic optical couplings are presented.
Peculiarities of propagation of femtosecond pulses through a focusing diffractive optical element (DOE) are considered. It is shown that the time delay between the pulse and phase wavefronts can be decreased by fabric...Peculiarities of propagation of femtosecond pulses through a focusing diffractive optical element (DOE) are considered. It is shown that the time delay between the pulse and phase wavefronts can be decreased by fabricating the DOE on the optimal curvilinear surface.展开更多
With the increasing demand for space optical communication security, space chaotic optical communication has attracted a great amount of attention. Compared with traditional space optical communication, a chaotic opti...With the increasing demand for space optical communication security, space chaotic optical communication has attracted a great amount of attention. Compared with traditional space optical communication, a chaotic optical communication system has a higher bit error rate(BER) for its complex system design. In order to decrease the BER of space chaotic optical communication systems, we introduce two diffractive optical elements(DOEs)at a transmitting terminal(Tx). That is because the commonly used reflective optical antenna at Tx blocks the central part of the transmission beam, which leads to a great amount of power consumption. Introducing the DOEs into the optical subsystem at Tx can reshape the transmission beam from a Gaussian distribution to a hollow Gaussian distribution so that the block of the secondary mirror in the reflective optical antenna can be avoided. In terms of the DOE influence on communication quality, we give a BER model based on a minimumshift-key(MSK) space uplink chaotic optical communication system to describe the DOE function. Based on the model, we further investigate the effect of the DOEs through analyzing the BER relationship versus basic system parameters based on the BER model. Both different mismatch conditions of chaotic systems and different atmospheric turbulence conditions are considered. These results will be helpful for the scheme design of space uplink chaotic optical communication systems.展开更多
In the integral imaging light field display, the introduction of a diffractive optical element (DOE) can solve the problem of limited depth of field of the traditional lens. However, the strong aberration of the DOE s...In the integral imaging light field display, the introduction of a diffractive optical element (DOE) can solve the problem of limited depth of field of the traditional lens. However, the strong aberration of the DOE significantly reduces the final display quality. Thus, herein, an end-to-end joint optimization method for optimizing DOE and aberration correction is proposed. The DOE model is established using thickness as the variable, and a deep learning network is built to preprocess the composite image loaded on the display panel. The simulation results show that the peak signal to noise ratio value of the optimized image increases by 8 dB, which confirms that the end-to-end joint optimization method can effectively reduce the aberration problem.展开更多
This paper presents the results of 15 years of studies in the field of terahertz holography at the Novosibirsk free electron laser.They cover two areas:research on obtaining holographic images in the terahertz range a...This paper presents the results of 15 years of studies in the field of terahertz holography at the Novosibirsk free electron laser.They cover two areas:research on obtaining holographic images in the terahertz range and the use of diffractive optical elements to form high-power terahertz radiation fields with specified characteristics(intensity,phase,and polarization),using well-studied and widely applied in the optical range methods of optical(analog),digital,and computer-generated holography.All experiments were performed with the application of high-power coherent monochromatic frequency-tunable radiation from the Novosibirsk free electron laser.The features of hologram registration in the terahertz range are described.Methods,technologies,and optical materials for terahertz holographic elements are discussed.A wide range of promising applications of high-power terahertz fields with a given spatial structure is considered.The results of the study of terahertz holograms recorded as digital holograms,as well as radiation-resistive optical elements realized as computer-synthesized holograms,are presented.展开更多
Membrane diffractive optical elements formed by fabricating microstructures on the substrates have two important characteristics,ultra-light mass(surface mass density<0.1 kg/m2)and loose surface shape tolerances(su...Membrane diffractive optical elements formed by fabricating microstructures on the substrates have two important characteristics,ultra-light mass(surface mass density<0.1 kg/m2)and loose surface shape tolerances(surface accuracy requirements are on the order of magnitude of centimeter).Large-aperture telescopes using a membrane diffractive optical element as the primary lens have super large aperture,light weight,and low cost at launch.In this paper,the research and development on space-based diffractive telescopes are classified and summarized.First,the imaging theory and the configuration of diffractive-optics telescopes are discussed.Then,the developments in diffractive telescopes are introduced.Finally,the development prospects for this technology used as a high-resolution space reconnaissance system in the future are summarized,and the critical and relevant work that China should carry out is put forward.展开更多
Diffractive optical elements attract a considerable amount of attention, mainly due to their potential applications in imaging coding, optical sensing, etc. Application of ferroelectric liquid crystals(FLCs) with phot...Diffractive optical elements attract a considerable amount of attention, mainly due to their potential applications in imaging coding, optical sensing, etc. Application of ferroelectric liquid crystals(FLCs) with photoalignment technology in diffractive optical elements results in a high efficiency and a fast response time. In this study we demonstrate a circular Dammann grating(CDG) with a diffraction efficiency of 84.5%. The achieved response time of 64 μs is approximately two orders of magnitude faster than the existing response time of nematic liquid crystal devices. By applying a low electric field(V = 6 V) to the FLC CDG, it is switched between the eight-order diffractive state and the transmissive diffraction-free state.展开更多
基金This project is supported by the National Natural Science Foundation of China under the Grant No. 19970438.
文摘The matrix eigenvalue method is used to analyze a laser resonator composed of diffraction optical elements. The results show that this type of resonator can separate fundamental mode and high order modes effectively. The output beams can be designed for different requests.
基金Project supported by the National Basic Research Program of China(Grant No.2013CBA01702)the National Natural Science Foundation of China(Grant Nos.11474206,91233202,11374216,and 11404224)+1 种基金the Scientific Research Project of Beijing Education Commission,China(Grant No.KM201310028005)the Scientific Research Base Development Program of the Beijing Municipal Commission of Education and the Beijing Youth Top-Notch Talent Training Plan,China(Grant No.CIT&TCD201504080)
文摘Diffractive optical elements(DOEs) with spectrum separation and beam concentration(SSBC) functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB301801)the National Natural Science Foundation of China (GrantNos. 91233202,10904099,11204188,61205097,and 11174211)
文摘In this paper,a novel method is proposed and employed to design a single diffractive optical element(DOE) for implementing spectrum-splitting and beam-concentration(SSBC) functions simultaneously.We develop an optimization algorithm,through which the SSBC DOE can be optimized within an arbitrary thickness range according to the limitations of modern photolithography technology.Theoretical simulation results reveal that the designed SSBC DOE has a high optical focusing efficiency.It is expected that the designed SSBC DOE should have practical applications in high-efficiency solar cell systems.
文摘1 Introduction 1.1 Advantages of DOE 1)High diffraction efficiency; 2)Dispersive; 3)More selectivity of designing parameters; 4)More selectivity of primary materials; 5)Can make components miniature,forming array and integration. 1.2 1.3 megapixel triplet plastic mobile
基金supported by the National Natural Science Foundation of China(Grant Nos.91233202,21173260,and 51072221)the National Basic Research Program of China(Grant No.2012CB932903)
文摘Based on the facts that multijunction solar cells can increase the efficiency and concentration can reduce the cost dramatically, a special design of parallel multijunction solar cells was presented. The design employed a diffractive optical element (DOE) to split and concentrate the sunlight. A rainbow region and a zero-order diffraction region were generated on the output plane where solar cells with corresponding band gaps were placed. An analytical expression of the light intensity distribution on the output plane of the special DOE was deduced, and the limiting photovoltaic efficiency of such parallel multijunction solar ceils was obtained based on Shockley-Queisser's theory. An efficiency exceeding the Shockley--Queisser limit (33%) can be expected using multijunction solar cells consisting of separately fabricated subcells. The results provide an important alternative approach to realize high photovoltaic efficiency without the need for expensive epitaxial technology widely used in tandem solar cells, thus stimulating the research and application of high efficiency and low cost solar cells.
基金Supported by the National Natural Science Foundation of China under Grant Nos 91233202,91433205 and 51421002the Chinese Academy of Sciences
文摘A spectrum-splitting and beam-concentrating (SSBC) diffractive optical element (DOE) for three-junction pho- tovoltaics (PV) system is designed and fabricated by five-circ/e micro-fabrication. The incident solar light is efficiently split into three sub-spectrum ranges and strongly concentrated on the focal plane, which can be di- rectly utilized by suitable spectrum-matching solar cells. The system concentration factor reaches 12x. Moreover, the designed wavelengths (450nm, 550nm and 65Onto) are spatially distributed on the focal plane, in good agree- ment with the theoretical results. The average optical effic/ency of all the cells over the three designed wavelengths is 60.07%. The SSBC DOE with a high concentration factor and a high optical efficiency provides a cost-effective approach to achieve higher PV conversion efficieneies.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.91233202,21173260,and 51072221)the National Basic Research Program of China(Grant No.2012CB932903
文摘Two improved algorithms are proposed to extend a diffractive optical element (DOE) to work under the broad spec- trum of sunlight. An optimum design has been found for the DOE, with a weighted average optical efficiency of about 6.8% better than that of the previous design. The optimization of designing high optical efficiency DOEs will pave the way for future designs of high-efficiency, low-cost lateral multijunction solar cells based on such a DOE.
基金partially supported by the National Key Basic Research Program of China(No.2013CB329202)the National Scientific Equipment Development SpecialFoundation of China(No.2011YQ03013401)+1 种基金the National Natural Science Foundation of China(No.61475021)the Beijing Natural Science Foundation(No.4152015)
文摘Diffractive optics is an important technique for beam shaping with high light efficiency and strong diffraction pattern flexibility. Since the diffraction angle is limited by the unit size of the diffractive optical element (DOE), the size of the required diffraction pattern is always rather small. In this Letter, refractive/diffractive hybrid optical elements (RDHOEs) consisting of a DOE and a lens are used to realize beam shaping for a large diffraction pattern. The lens, as the component of the RDHOEs, can not only be concave but also convex, and the double sampling Fresnel diffraction algorithm is developed for the design of these two types of RDHOEs. The simulation and experimental results provide solid evidence to demonstrate the proposed method with the pure phase spatial light modulator.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)the National Natural Science Foundation of China(Nos.62235009,62035003,62205173,61935013,62375181,61975133,and 12104318)+1 种基金the Science and Technology Innovation Commission of Shenzhen(Nos.KQTD20170330110444030 and JCYJ20200109114018750)the Scientific Instrument Developing Project of Shenzhen University(No.2023YQ001).
文摘Diffractive optical elements(DOEs)are intricately designed devices with the purpose of manipulating light fields by precisely modifying their wavefronts.The concept of DOEs has its origins dating back to 1948 when D.Gabor first introduced holography.Subsequently,researchers introduced binary optical elements(BOEs),including computer-generated holograms(CGHs),as a distinct category within the realm of DOEs.This was the first revolution in optical devices.The next major breakthrough in light field manipulation occurred during the early 21st century,marked by the advent of metamaterials and metasurfaces.Metasurfaces are particularly appealing due to their ultra-thin,ultra-compact properties and their capacity to exert precise control over virtually every aspect of light fields,including amplitude,phase,polarization,wavelength/frequency,angular momentum,etc.The advancement of light field manipulation with micro/nano-structures has also enabled various applications in fields such as information acquisition,transmission,storage,processing,and display.In this review,we cover the fundamental science,cutting-edge technologies,and wide-ranging applications associated with micro/nano-scale optical devices for regulating light fields.We also delve into the prevailing challenges in the pursuit of developing viable technology for real-world applications.Furthermore,we offer insights into potential future research trends and directions within the realm of light field manipulation.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0206004)the National Natural Science Foundation of China(Grant No.11375160)the Science and Technology Fund from the Plasma Physics Laboratory,China(Grant No.ZY2018-01)。
文摘Annular-focused beams have attracted attention because of their novel properties and applications in optical trapping, high resolution microscopy, and laser-induced periodic surface structuring. Generation of this beam is very important and necessary. In this article, a novel design of zone plate for forming the annular-focused beams is proposed. The design principle is introduced, and the characteristics of zone plate are analyzed by numerical simulation. The result shows that the zone plate can form a monochromatic ring-shaped intensity distribution in the focal plane. And the design method is also generally suitable for designing the other optical elements to generate the annular-focused beams.
基金This work has been partially supported by NIH(SC COBRE P20RR021949 and Career Award 1k25hl088262-01)NSF(MRI CBET-0923311 and SC EPSCoR RII EPS-0903795 through SC GEAR program)+3 种基金The National Natural Science Foundation of China(31171372,61078067)Guangdong Province Science and Technology Project(2010B060300002)Shenzhen University Application Technology Development Project(201136,CXB201104220021A,JC201005250032A,200854)the Fundamental Research Funds for the Central Universities(K50510050006).
文摘Multifocal multiphoton microscopy(MMM)has recently become an important tool in biomedicine for performing three-dimensional fastfluorescence imaging.Using various beamsplitting techniques,MMM splits the near-infrared laser beam into multiple beamlets and produces a multifocal array on the sample for parallel multiphoton excitation and then recordsfluorescence signal from all foci simultaneously with an area array detector,which significantly improves the imaging speed of multiphoton microscopy and allows for high efficiency in use of the excitation light.In this paper,we discuss the features of several MMM setups using different beamsplitting devices,including a Nipkow spinning disk,a microlens array,a set of beamsplitting mirrors,or a diffractive optical element(DOE).In particular,we present our recent work on the development of an MMM using a spatial light modulator(SLM).
基金The authors acknowledge the support from National Natural Science Foundation of China (60125512, 60177016)
文摘Diffractive optical elements such as the complementary Dammann gratings are incorporated for dynamic optical fiber splitting and combining. Experimental results of 1×8 dynamic optical couplings are presented.
文摘Peculiarities of propagation of femtosecond pulses through a focusing diffractive optical element (DOE) are considered. It is shown that the time delay between the pulse and phase wavefronts can be decreased by fabricating the DOE on the optimal curvilinear surface.
基金supported by Joint Funds of Space Science and Technology(No.6141B060307)Suzhou Technology Innovative for Key Industries Program of China(No.SYG201729)+2 种基金National Natural Science Foundation of China(No.61205045)Fundamental Research Funds for the Central Universities(No.021314380152)Six Talent Peaks Project in Jiangsu Province(No.KTHY-003)
文摘With the increasing demand for space optical communication security, space chaotic optical communication has attracted a great amount of attention. Compared with traditional space optical communication, a chaotic optical communication system has a higher bit error rate(BER) for its complex system design. In order to decrease the BER of space chaotic optical communication systems, we introduce two diffractive optical elements(DOEs)at a transmitting terminal(Tx). That is because the commonly used reflective optical antenna at Tx blocks the central part of the transmission beam, which leads to a great amount of power consumption. Introducing the DOEs into the optical subsystem at Tx can reshape the transmission beam from a Gaussian distribution to a hollow Gaussian distribution so that the block of the secondary mirror in the reflective optical antenna can be avoided. In terms of the DOE influence on communication quality, we give a BER model based on a minimumshift-key(MSK) space uplink chaotic optical communication system to describe the DOE function. Based on the model, we further investigate the effect of the DOEs through analyzing the BER relationship versus basic system parameters based on the BER model. Both different mismatch conditions of chaotic systems and different atmospheric turbulence conditions are considered. These results will be helpful for the scheme design of space uplink chaotic optical communication systems.
基金supported by the National Natural Science Foundation of China(Nos.62175015,61905019,and 62075016)Fundamental Research Funds for the Central Universities(No.2021RC13)。
文摘In the integral imaging light field display, the introduction of a diffractive optical element (DOE) can solve the problem of limited depth of field of the traditional lens. However, the strong aberration of the DOE significantly reduces the final display quality. Thus, herein, an end-to-end joint optimization method for optimizing DOE and aberration correction is proposed. The DOE model is established using thickness as the variable, and a deep learning network is built to preprocess the composite image loaded on the display panel. The simulation results show that the peak signal to noise ratio value of the optimized image increases by 8 dB, which confirms that the end-to-end joint optimization method can effectively reduce the aberration problem.
基金The studies described in“Imaging devices”,“Vortex microbeam arrays with a given topological charge in the Talbot configuration”,“Vector vortex beams”,“Generation of vortex surface plasmon polaritons using perfect beams”sections were supported by the Russian Science Foundation grant No.19-12-00103,“Classical holography imaging”section by RFBR No.18-32-00407“Diffractive optical elements”,“Material and technologies for DOE manufacturing”,“Binary and multilevel DOEs for focusing into given 2D and 3D areas”,“DOE for mode content control”and“Multichannel free space communication and lidar”sections by RSF No.19-72-20202.
文摘This paper presents the results of 15 years of studies in the field of terahertz holography at the Novosibirsk free electron laser.They cover two areas:research on obtaining holographic images in the terahertz range and the use of diffractive optical elements to form high-power terahertz radiation fields with specified characteristics(intensity,phase,and polarization),using well-studied and widely applied in the optical range methods of optical(analog),digital,and computer-generated holography.All experiments were performed with the application of high-power coherent monochromatic frequency-tunable radiation from the Novosibirsk free electron laser.The features of hologram registration in the terahertz range are described.Methods,technologies,and optical materials for terahertz holographic elements are discussed.A wide range of promising applications of high-power terahertz fields with a given spatial structure is considered.The results of the study of terahertz holograms recorded as digital holograms,as well as radiation-resistive optical elements realized as computer-synthesized holograms,are presented.
基金Project supported by the National Natural Science Foundation of China(No.11874091)。
文摘Membrane diffractive optical elements formed by fabricating microstructures on the substrates have two important characteristics,ultra-light mass(surface mass density<0.1 kg/m2)and loose surface shape tolerances(surface accuracy requirements are on the order of magnitude of centimeter).Large-aperture telescopes using a membrane diffractive optical element as the primary lens have super large aperture,light weight,and low cost at launch.In this paper,the research and development on space-based diffractive telescopes are classified and summarized.First,the imaging theory and the configuration of diffractive-optics telescopes are discussed.Then,the developments in diffractive telescopes are introduced.Finally,the development prospects for this technology used as a high-resolution space reconnaissance system in the future are summarized,and the critical and relevant work that China should carry out is put forward.
基金supported by the National Natural Science Foundation of China (Nos. 61405009,61875004,61705067)the Defense Industrial Technology Development Program (No. JCKY2019601C101)+1 种基金the Shanghai Pujiang Program (16PJ1402200)supported by the Russian Science Foundation (No. 20-19-00201)。
文摘Diffractive optical elements attract a considerable amount of attention, mainly due to their potential applications in imaging coding, optical sensing, etc. Application of ferroelectric liquid crystals(FLCs) with photoalignment technology in diffractive optical elements results in a high efficiency and a fast response time. In this study we demonstrate a circular Dammann grating(CDG) with a diffraction efficiency of 84.5%. The achieved response time of 64 μs is approximately two orders of magnitude faster than the existing response time of nematic liquid crystal devices. By applying a low electric field(V = 6 V) to the FLC CDG, it is switched between the eight-order diffractive state and the transmissive diffraction-free state.