The aberration field of an optical system with a tilted pupil is explored through expanding the vector expressions of the third-order wavefront aberrations. First, the vector forms of the wavefront aberrations are mod...The aberration field of an optical system with a tilted pupil is explored through expanding the vector expressions of the third-order wavefront aberrations. First, the vector forms of the wavefront aberrations are modified to obtain the aberration expressions with the pupil tilted; full field displays of coma and astigmatism in this situation are given. Then, the third-order aberration formulas with the pupil decentered and tilted simultaneously are derived and discussed. Finally, an example is taken to certify the validity of aberration distribution properties.展开更多
Precision is one of the most important aspects of manufacturing.High precision creates high quality,high performance,exchangeability,reliability,and added value for industrial products.Over the past decades,remarkable...Precision is one of the most important aspects of manufacturing.High precision creates high quality,high performance,exchangeability,reliability,and added value for industrial products.Over the past decades,remarkable advances have been achieved in the area of high-precision manufacturing technologies,where the form accuracy approaches the nanometer level and surface roughness the atomic level.These extremely high precision manufacturing technologies enable the development of high-performance optical elements,semiconductor substrates,biomedical parts,and so on,thereby enhancing the ability of human beings to explore the macroand microscopic mysteries and potentialities of the natural world.In this paper,state-of-the-art high-precision material removal manufacturing technologies,especially ultraprecision cutting,grinding,deterministic form correction polishing,and supersmooth polishing,are reviewed and compared with insights into their principles,methodologies,and applications.The key issues in extreme precision manufacturing that should be considered for future R&D are discussed.展开更多
Topological phase of newly found matter has aroused wide interests, especially related with the external periodical modulating. With the help of the Floquet theory, we investigate the possibility of externally manipul...Topological phase of newly found matter has aroused wide interests, especially related with the external periodical modulating. With the help of the Floquet theory, we investigate the possibility of externally manipulating the topological property in a HgTe/CdTe quantum well system with the polarized optical field. We give the phase diagram, showing that by modulating the parameters of the polarized optical field, especially the phase, the topological phase transition can be realized in the QW and lead to the so-called Floquet topological insulator. When the optical field is weak, the driven QSH state of QW is robust with the optical field. However, when the optical field is relatively larger, the group velocity of edge states and the gap between the bulk states exhibit certain oscillations. The implications of our results are discussed.展开更多
Strontium-zinc-oxide（SrZnO） films forming the semiconductor layers of thin-film transistors（TFTs） are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-...Strontium-zinc-oxide（SrZnO） films forming the semiconductor layers of thin-film transistors（TFTs） are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-state current can be dramatically reduced by three orders of magnitude. This dramatic improvement is attributed to the incorporation of strontium, which suppresses carrier generation, thereby improving the TFT. Additionally, the presence of strontium inhibits the formation of zinc oxide（ZnO） with the hexagonal wurtzite phase and permits the formation of an unusual phase of ZnO, thus significantly changing the surface morphology of ZnO and effectively reducing the trap density of the channel.展开更多
The integrated manufacturing technology is introduced to improve the imaging quality of an off-axis three-mirror anastigmatic （TMA） system. With the integration of system design, manufacturing of highly precise opti...The integrated manufacturing technology is introduced to improve the imaging quality of an off-axis three-mirror anastigmatic （TMA） system. With the integration of system design, manufacturing of highly precise optical elements, simulation and evaluation capabilities of the manufactured system, and testing and alignment with the same fiducial, we can efficiently and precisely achieve high quality of an optical system. In order to prove the efficiency of this technology, we design an off-axis TMA system with MTF invariance better than 0.50 （57 lp/mm）, and manufacture the aspherical surfaces of this optical system with surface figure error better than ;λ/50 （RMS, λ = 632.8 nm）. We develop an interface software named MetroMax to achieve the connection between the final surface figure and the optical design software. The MetorMax also forecasts the imaging quality of the system, and guide us in aligning the system with a same fiducial with the whole field of view approached λ/14 and MTF invariance better than 0.95. To confirm the imaging system after integrated manufacturing, we test the system on the ground and orbit; the result proves effective improvement in the imaging quality of the optical system.展开更多
Null compensation interferometry is the primary testing method for the manufacture of ultra-high-precision aspheric mirrors.The crosstalk fringes generated by stray light in interferometry can affect accuracy and pote...Null compensation interferometry is the primary testing method for the manufacture of ultra-high-precision aspheric mirrors.The crosstalk fringes generated by stray light in interferometry can affect accuracy and potentially prevent the testing from proceeding normally.Position errors include the decenter error,tilt error,and distance error.During the testing process,position errors will impact the testing accuracy and the crosstalk fringes generated by stray light.To determine the specific impact of position errors,we use the concept of Hindle shell testing of a convex aspheric mirror,and propose the simulation method of crosstalk fringes in null compensation interferometry.We also propose evaluation indices of crosstalk fringes in interferometry and simulate the influence of position errors on the crosstalk fringes.This work aims to help improve the design of compensation interferometry schemes,enhance the feasibility of the design,reduce engineering risks,and improve efficiency.展开更多
In this paper, we present an infrared transparent frequency selective surface（ITFSS） based on iterative metallic meshes, which possesses the properties of high transmittance in infrared band and band-pass effect in ...In this paper, we present an infrared transparent frequency selective surface（ITFSS） based on iterative metallic meshes, which possesses the properties of high transmittance in infrared band and band-pass effect in millimeter wave band. Cross-slot units are designed on the iterative metallic meshes, which is composed of two same square metallic meshes with a misplaced overlap. In the infrared band of 3–5 μm, the ITFSS has an average transmittance of 80% with a Mg F2 substrate. In the millimeter wave band, a transmittance of-0.74 d B at the resonance frequency of 39.4 GHz is obtained. Moreover, theoretical simulations of the ITFSS diffractive characteristics and transmittance response are also investigated in detail. This ITFSS may be an efficient way to achieve the metamaterial millimeter wave/infrared functional film.展开更多
In order to realize the tunable performance of a frequency selective surface （FSS）, a new unit cell is designed in this paper by properly adding two metal shorts to the ring slot. Based on the spectral-domain method...In order to realize the tunable performance of a frequency selective surface （FSS）, a new unit cell is designed in this paper by properly adding two metal shorts to the ring slot. Based on the spectral-domain method, the frequency responses of the FSS structure with two shorts per slot ring are analysed for both the horizontal and the vertical polarizations at the normal incidence. It is demonstrated that the presence of the metal shorts does not affect the resonant frequency of the horizontally polarized wave but doubles the resonant frequency of the vertically polarized wave. Therefore based on the analysis of the novel transmission properties, a new approach to adjusting the resonant frequency by rotating the FSS screen 90° is presented in this paper.展开更多
Optical windows with external surfaces shaped to satisfy operational environment needs are known as special windows. A novel special window, a sphere-cone-polynomial （SCP） window, is proposed. The formulas of this w...Optical windows with external surfaces shaped to satisfy operational environment needs are known as special windows. A novel special window, a sphere-cone-polynomial （SCP） window, is proposed. The formulas of this window shape are given. An SCP MgF2 window with a fineness ratio of 1.33 is designed as an example. The field-of-regard （FOR） angle is ±75°. From the window system simulation results obtained with the calculated fluid dynamics （CFD） and optical design software, we find that compared to the conventional window forms, the SCP shape can not only introduce relatively less drag in the airflow, but also have the minimal effect on imaging. So the SCP window optical system can achieve a high image quality across a super wide FOR without adding extra aberration correctors. The tolerance analysis results show that the optical performance can be maintained with a reasonable fabricating tolerance to manufacturing errors.展开更多
Wavefront coding （WFC） is kind of computational imaging technique that controls misfocus and misfocusrelated aberrations of optical systems by appending a specially designed phase distribution to the pupil function....Wavefront coding （WFC） is kind of computational imaging technique that controls misfocus and misfocusrelated aberrations of optical systems by appending a specially designed phase distribution to the pupil function. This technology has been applied in many fields to increase the performance or/and reduce the cost of imaging systems. The application of WFC technology on an off-axis three-mirror anastigmatic （TMA） system has been proposed in our previous work. In this letter, we describe the alignment, the imaging experiment and image restoration of an actual TMA system with WFC technology.展开更多
A dual-band flexible frequency selective surface （FSS） with miniaturized elements and maximally flat （Butterworth） response is presented in this paper. It is composed of three metallic layers, which are fabricated...A dual-band flexible frequency selective surface （FSS） with miniaturized elements and maximally flat （Butterworth） response is presented in this paper. It is composed of three metallic layers, which are fabricated on thin flexible polyimide substrates and bonded together using thin bonding films. The overall thickness of the proposed structure is only about 0.3 mm, making it an attractive choice for conformal FSS applications. All the three layers can constitute a miniaturized- element FSS （MEFSS） and produce the first pass-band with miniaturization property, while the up and bottom layers can constitute a symmetric biplanar FSS and produce the second pass-band with maximally fiat （Butterworth） response. The two pass-bands are independent and there is a wide band spacing up to 30 GHz between them. The principles of operation, the simulated results by using the vector modal matching method, and the experimental values of the fabricated prototype are also presented and discussed.展开更多
Polymer photovoltaic(PV)cells based on UV-ozone(UVO)-treated indium vanadium oxide(IVO)anodes are developed.The performance of cells with UVO-treated IVO film anodes without interfacial layers was significantly improv...Polymer photovoltaic(PV)cells based on UV-ozone(UVO)-treated indium vanadium oxide(IVO)anodes are developed.The performance of cells with UVO-treated IVO film anodes without interfacial layers was significantly improved compared with those containing untreated IVO anodes.The origin of the enhancement is investigated by atomic force microscopy and photoelectron spectroscopy measurements.The results demonstrate that UVO treatment can smooth the IVO surface,and increase the work function of IVO films due to the removal of carbon contamination and a dipole resulting from a surface rich in negatively charged oxygen.UVO-treated IVO films are potential electrode materials for polymer PV cells.展开更多
In this work,a simple fabrication method of germanium-based metasurfaces is proposed,where the deposited Al_(2)O_(3) layer with high selectivity is chosen as the hard mask and retained after the dry etching process.Th...In this work,a simple fabrication method of germanium-based metasurfaces is proposed,where the deposited Al_(2)O_(3) layer with high selectivity is chosen as the hard mask and retained after the dry etching process.The simulation and experimental characterization results verify the feasibility of the fabrication method.The experimental study on the fabrication methods of germanium-based metasurfaces is very significant as the meta-atoms with a higher refractive index can achieve 0 to 2πtransmission phase variation with a smaller period under the same thickness-to-period ratio,which is consistent with the requirement of the period miniaturization in some cases.展开更多
Micro/nanoprocessing of graphene surfaces has attracted significant interest for both science and applications due to its effective modulation of material properties,which,however,is usually restricted by the disadvan...Micro/nanoprocessing of graphene surfaces has attracted significant interest for both science and applications due to its effective modulation of material properties,which,however,is usually restricted by the disadvantages of the current fabrication methods.Here,by exploiting cylindrical focusing of a femtosecond laser on graphene oxide(GO)films,we successfully produce uniform subwavelength grating structures at high speed along with a simultaneous in situ photoreduction process.Strikingly,the well-defined structures feature orientations parallel to the laser polarization and significant robustness against distinct perturbations.The proposed model and simulations reveal that the structure formation is based on the transverse electric(TE)surface plasmons triggered by the gradient reduction of the GO film from its surface to the interior,which eventually results in interference intensity fringes and spatially periodic interactions.Further experiments prove that such a regular structured surface can cause enhanced optical absorption(>20%)and an anisotropic photoresponse(~0.46 ratio)for the reduced GO film.Our work not only provides new insights into understanding the laser-GO interaction but also lays a solid foundation for practical usage of femtosecond laser plasmonic lithography,with the prospect of expansion to other two-dimensional materials for novel device applications.展开更多
We implemented a stitching swing arm profilometer(SSAP) test for the inner and outer regions of a large aspheric surface with a short arm. The SSAP was more capable of improving sampling density of surface and was les...We implemented a stitching swing arm profilometer(SSAP) test for the inner and outer regions of a large aspheric surface with a short arm. The SSAP was more capable of improving sampling density of surface and was less sensitive to system error, like vibration noise and air-table noise. Firstly, a calculation model was built to evaluate the sampling density of the SSAP test. Then, sensitivity to system noise was tested when different lengths of arm were used. At the end, an experiment on a 3 m diameter aspheric mirror was implemented, where test efficiency was promoted, and high sampling density was achieved.展开更多
A rigid conformal （RC） lap can smooth mid-spatial-frequency （MSF） errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing effi...A rigid conformal （RC） lap can smooth mid-spatial-frequency （MSF） errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing efficiency performance is poorer than expected, and existing smoothing models cannot explicitly specify the methods to improve this efficiency. We presented an explicit time-dependent smoothing evaluation model that contained specific smoothing parameters directly derived from the parametric smoothing model and the Preston equation. Based on the time-dependent model, we proposed a strategy to improve the RC-lap smoothing efficiency, which incorporated the theoretical model, tool optimization, and efficiency limit determination. Two sets of smoothing experiments were performed to demonstrate the smoothing efficiency achieved using the time-dependent smoothing model. A high, theory-like tool influence function and a limiting toolspeed of 300 RPM were obtained.展开更多
Magnetorheological finishing(MRF)technology is widely used in the fabrication of high-precision optical elements.The material removal mechanism of MRF has not been fully understood because MRF technology involves the ...Magnetorheological finishing(MRF)technology is widely used in the fabrication of high-precision optical elements.The material removal mechanism of MRF has not been fully understood because MRF technology involves the integration of electromagnetics,contact mechanics,and materials science.In this study,the rheological properties of the MR polishing fluid in oscillation model have been investigated.We propose that the shear-thinned MR polishing fluid over the polishing area should be considered a dense granular flow,based on which a new contact model of MRF over the polishing area has been constructed.Removal function and processing force test experiments were conducted under different working gaps.The normal pressure and effective friction equations over the polishing area were built based on the continuous medium and dense granular flow theories.Then,a novel MRF material removal model was established.A comparison of the results of the theoretical model with actual polishing results demonstrated the accuracy of the established model.The novel model proposed herein reveals the generation mechanism of shear force over a polished workpiece and realizes effective decoupling of the main processing parameters that influence the material removal of MRF.The results of this study will provide new and effective theoretical guidance for the process optimization and technology improvement of MRF.展开更多
In common plasmonic structures,absorption and radiation losses are often mutually restricted and can seriously influence the device performance.The current study presents a compound structure composed of multilayer gr...In common plasmonic structures,absorption and radiation losses are often mutually restricted and can seriously influence the device performance.The current study presents a compound structure composed of multilayer grating stripes and multilayer shallow trenches.A small depth was adopted for the trench configuration to exclude the extra bend loss.These two sections supported Fabry–Perot resonance and cavity modes,respectively,with hybrid modes formed through intercoupling.In addition,the total loss for the entire framework was clearly reduced due to the introduction of the trench geometry,indicating that both absorption and radiation losses were successfully taken into consideration in the compound structure.Significantly,such a low loss realized by the hybridization of surface plasmon polariton modes has rarely been seen before.Moreover,the debatable relationship between the total and partial quality factors was described for the first time based on a hybrid mode analysis to establish a new approach to investigate the different resonance modes.In the detailed calculation process,the relative electric field intensity was first adopted to stipulate the effective areas for the various modes,which is more reasonable than using the common definition that is based on a unit structure.The multilayer trench grating exhibited a relatively low loss without weakening energy localization,which is significant in the design of plasmonic devices.展开更多
The demand for space-borne telescopes with an aperture of 20 m is forcing the development of large diameter diffractive Fresnel zone lenses（FZLs） on membranes. However, due to the fabrication errors of multi-level m...The demand for space-borne telescopes with an aperture of 20 m is forcing the development of large diameter diffractive Fresnel zone lenses（FZLs） on membranes. However, due to the fabrication errors of multi-level microstructures, the real diffraction efficiency is always significantly smaller than the theoretical value. In this Letter,the effects of a set of fabrication errors on the diffraction efficiency for a diffractive membrane are studied. In order to verify the proposed models, a 4-level membrane FZL with a diameter of 320 mm is fabricated. The fabrication errors of the membrane FZL are measured, and its diffraction efficiency in the ＋1 order is also tested.The results show that the tested diffraction efficiency is very close to the calculated value based on the proposed models. It is expected that the present work could play a theoretical guiding role in the future development of space-borne diffractive telescopes.展开更多
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China （Grant No 61007009）.
文摘The aberration field of an optical system with a tilted pupil is explored through expanding the vector expressions of the third-order wavefront aberrations. First, the vector forms of the wavefront aberrations are modified to obtain the aberration expressions with the pupil tilted; full field displays of coma and astigmatism in this situation are given. Then, the third-order aberration formulas with the pupil decentered and tilted simultaneously are derived and discussed. Finally, an example is taken to certify the validity of aberration distribution properties.
文摘Precision is one of the most important aspects of manufacturing.High precision creates high quality,high performance,exchangeability,reliability,and added value for industrial products.Over the past decades,remarkable advances have been achieved in the area of high-precision manufacturing technologies,where the form accuracy approaches the nanometer level and surface roughness the atomic level.These extremely high precision manufacturing technologies enable the development of high-performance optical elements,semiconductor substrates,biomedical parts,and so on,thereby enhancing the ability of human beings to explore the macroand microscopic mysteries and potentialities of the natural world.In this paper,state-of-the-art high-precision material removal manufacturing technologies,especially ultraprecision cutting,grinding,deterministic form correction polishing,and supersmooth polishing,are reviewed and compared with insights into their principles,methodologies,and applications.The key issues in extreme precision manufacturing that should be considered for future R&D are discussed.
文摘Topological phase of newly found matter has aroused wide interests, especially related with the external periodical modulating. With the help of the Floquet theory, we investigate the possibility of externally manipulating the topological property in a HgTe/CdTe quantum well system with the polarized optical field. We give the phase diagram, showing that by modulating the parameters of the polarized optical field, especially the phase, the topological phase transition can be realized in the QW and lead to the so-called Floquet topological insulator. When the optical field is weak, the driven QSH state of QW is robust with the optical field. However, when the optical field is relatively larger, the group velocity of edge states and the gap between the bulk states exhibit certain oscillations. The implications of our results are discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.6140031454)the Innovation Program of Chinese Academy of Sciences and State Key Laboratory of Luminescence and Applications
文摘Strontium-zinc-oxide（SrZnO） films forming the semiconductor layers of thin-film transistors（TFTs） are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-state current can be dramatically reduced by three orders of magnitude. This dramatic improvement is attributed to the incorporation of strontium, which suppresses carrier generation, thereby improving the TFT. Additionally, the presence of strontium inhibits the formation of zinc oxide（ZnO） with the hexagonal wurtzite phase and permits the formation of an unusual phase of ZnO, thus significantly changing the surface morphology of ZnO and effectively reducing the trap density of the channel.
基金This work was supported by the National Natural Science Foundation of China （No. 61036015） and the National High Technology Research ＆ Development Program of China （No. O8663NJ090）.
文摘The integrated manufacturing technology is introduced to improve the imaging quality of an off-axis three-mirror anastigmatic （TMA） system. With the integration of system design, manufacturing of highly precise optical elements, simulation and evaluation capabilities of the manufactured system, and testing and alignment with the same fiducial, we can efficiently and precisely achieve high quality of an optical system. In order to prove the efficiency of this technology, we design an off-axis TMA system with MTF invariance better than 0.50 （57 lp/mm）, and manufacture the aspherical surfaces of this optical system with surface figure error better than ;λ/50 （RMS, λ = 632.8 nm）. We develop an interface software named MetroMax to achieve the connection between the final surface figure and the optical design software. The MetorMax also forecasts the imaging quality of the system, and guide us in aligning the system with a same fiducial with the whole field of view approached λ/14 and MTF invariance better than 0.95. To confirm the imaging system after integrated manufacturing, we test the system on the ground and orbit; the result proves effective improvement in the imaging quality of the optical system.
基金National Key Research and Development Program of China(2022YFB3403404)Youth Innovation Promotion Association,CAS(2022213)National Natural Science Foundation of China(62127901 and 62305334).
文摘Null compensation interferometry is the primary testing method for the manufacture of ultra-high-precision aspheric mirrors.The crosstalk fringes generated by stray light in interferometry can affect accuracy and potentially prevent the testing from proceeding normally.Position errors include the decenter error,tilt error,and distance error.During the testing process,position errors will impact the testing accuracy and the crosstalk fringes generated by stray light.To determine the specific impact of position errors,we use the concept of Hindle shell testing of a convex aspheric mirror,and propose the simulation method of crosstalk fringes in null compensation interferometry.We also propose evaluation indices of crosstalk fringes in interferometry and simulate the influence of position errors on the crosstalk fringes.This work aims to help improve the design of compensation interferometry schemes,enhance the feasibility of the design,reduce engineering risks,and improve efficiency.
基金supported by the National Natural Science Foundation of China(Grant No.61401424)
文摘In this paper, we present an infrared transparent frequency selective surface（ITFSS） based on iterative metallic meshes, which possesses the properties of high transmittance in infrared band and band-pass effect in millimeter wave band. Cross-slot units are designed on the iterative metallic meshes, which is composed of two same square metallic meshes with a misplaced overlap. In the infrared band of 3–5 μm, the ITFSS has an average transmittance of 80% with a Mg F2 substrate. In the millimeter wave band, a transmittance of-0.74 d B at the resonance frequency of 39.4 GHz is obtained. Moreover, theoretical simulations of the ITFSS diffractive characteristics and transmittance response are also investigated in detail. This ITFSS may be an efficient way to achieve the metamaterial millimeter wave/infrared functional film.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61172012)
文摘In order to realize the tunable performance of a frequency selective surface （FSS）, a new unit cell is designed in this paper by properly adding two metal shorts to the ring slot. Based on the spectral-domain method, the frequency responses of the FSS structure with two shorts per slot ring are analysed for both the horizontal and the vertical polarizations at the normal incidence. It is demonstrated that the presence of the metal shorts does not affect the resonant frequency of the horizontally polarized wave but doubles the resonant frequency of the vertically polarized wave. Therefore based on the analysis of the novel transmission properties, a new approach to adjusting the resonant frequency by rotating the FSS screen 90° is presented in this paper.
基金the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.61007009)
文摘Optical windows with external surfaces shaped to satisfy operational environment needs are known as special windows. A novel special window, a sphere-cone-polynomial （SCP） window, is proposed. The formulas of this window shape are given. An SCP MgF2 window with a fineness ratio of 1.33 is designed as an example. The field-of-regard （FOR） angle is ±75°. From the window system simulation results obtained with the calculated fluid dynamics （CFD） and optical design software, we find that compared to the conventional window forms, the SCP shape can not only introduce relatively less drag in the airflow, but also have the minimal effect on imaging. So the SCP window optical system can achieve a high image quality across a super wide FOR without adding extra aberration correctors. The tolerance analysis results show that the optical performance can be maintained with a reasonable fabricating tolerance to manufacturing errors.
文摘Wavefront coding （WFC） is kind of computational imaging technique that controls misfocus and misfocusrelated aberrations of optical systems by appending a specially designed phase distribution to the pupil function. This technology has been applied in many fields to increase the performance or/and reduce the cost of imaging systems. The application of WFC technology on an off-axis three-mirror anastigmatic （TMA） system has been proposed in our previous work. In this letter, we describe the alignment, the imaging experiment and image restoration of an actual TMA system with WFC technology.
基金Project supported by the Third Innovation Fund of Changchun Institute of Optics and Fine Mechanics and Physics(Grant No.093Y32J090)
文摘A dual-band flexible frequency selective surface （FSS） with miniaturized elements and maximally flat （Butterworth） response is presented in this paper. It is composed of three metallic layers, which are fabricated on thin flexible polyimide substrates and bonded together using thin bonding films. The overall thickness of the proposed structure is only about 0.3 mm, making it an attractive choice for conformal FSS applications. All the three layers can constitute a miniaturized- element FSS （MEFSS） and produce the first pass-band with miniaturization property, while the up and bottom layers can constitute a symmetric biplanar FSS and produce the second pass-band with maximally fiat （Butterworth） response. The two pass-bands are independent and there is a wide band spacing up to 30 GHz between them. The principles of operation, the simulated results by using the vector modal matching method, and the experimental values of the fabricated prototype are also presented and discussed.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences,the National Natural Science Foundation of China(Nos 51102228 and 61106057)the Science and Technology Development Project of Jilin Province of China(Nos 20090346 and 20100570).
文摘Polymer photovoltaic(PV)cells based on UV-ozone(UVO)-treated indium vanadium oxide(IVO)anodes are developed.The performance of cells with UVO-treated IVO film anodes without interfacial layers was significantly improved compared with those containing untreated IVO anodes.The origin of the enhancement is investigated by atomic force microscopy and photoelectron spectroscopy measurements.The results demonstrate that UVO treatment can smooth the IVO surface,and increase the work function of IVO films due to the removal of carbon contamination and a dipole resulting from a surface rich in negatively charged oxygen.UVO-treated IVO films are potential electrode materials for polymer PV cells.
基金supported by the National Natural Science Foundation of China(No.12204478).
文摘In this work,a simple fabrication method of germanium-based metasurfaces is proposed,where the deposited Al_(2)O_(3) layer with high selectivity is chosen as the hard mask and retained after the dry etching process.The simulation and experimental characterization results verify the feasibility of the fabrication method.The experimental study on the fabrication methods of germanium-based metasurfaces is very significant as the meta-atoms with a higher refractive index can achieve 0 to 2πtransmission phase variation with a smaller period under the same thickness-to-period ratio,which is consistent with the requirement of the period miniaturization in some cases.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.91750205,11674178,and 11804334)the Jilin Provincial Science&Technology Development Project(Grant No.20180414019GH)the K.C.Wong Education Foundation(GJTD-2018-08).
文摘Micro/nanoprocessing of graphene surfaces has attracted significant interest for both science and applications due to its effective modulation of material properties,which,however,is usually restricted by the disadvantages of the current fabrication methods.Here,by exploiting cylindrical focusing of a femtosecond laser on graphene oxide(GO)films,we successfully produce uniform subwavelength grating structures at high speed along with a simultaneous in situ photoreduction process.Strikingly,the well-defined structures feature orientations parallel to the laser polarization and significant robustness against distinct perturbations.The proposed model and simulations reveal that the structure formation is based on the transverse electric(TE)surface plasmons triggered by the gradient reduction of the GO film from its surface to the interior,which eventually results in interference intensity fringes and spatially periodic interactions.Further experiments prove that such a regular structured surface can cause enhanced optical absorption(>20%)and an anisotropic photoresponse(~0.46 ratio)for the reduced GO film.Our work not only provides new insights into understanding the laser-GO interaction but also lays a solid foundation for practical usage of femtosecond laser plasmonic lithography,with the prospect of expansion to other two-dimensional materials for novel device applications.
基金supported by the National Natural Science Foundation of China(Nos.61605202 and 6180031521)Key Project of Chinese National Programs for Fundamental Research and Development(No.2016YFB0500100)+1 种基金Equipment Pre-research Project(No.30502010501HT01)Civil Space Pre-research Program(No.D040101)
文摘We implemented a stitching swing arm profilometer(SSAP) test for the inner and outer regions of a large aspheric surface with a short arm. The SSAP was more capable of improving sampling density of surface and was less sensitive to system error, like vibration noise and air-table noise. Firstly, a calculation model was built to evaluate the sampling density of the SSAP test. Then, sensitivity to system noise was tested when different lengths of arm were used. At the end, an experiment on a 3 m diameter aspheric mirror was implemented, where test efficiency was promoted, and high sampling density was achieved.
基金This research is financially supported by the National Natural Science of China （NSFC） （61210015） and Youth Foundation of National Natural Science Foundation （61605202）.
文摘A rigid conformal （RC） lap can smooth mid-spatial-frequency （MSF） errors, which are naturally smaller than the tool size, while still removing large-scale errors in a short time. However, the RC-lap smoothing efficiency performance is poorer than expected, and existing smoothing models cannot explicitly specify the methods to improve this efficiency. We presented an explicit time-dependent smoothing evaluation model that contained specific smoothing parameters directly derived from the parametric smoothing model and the Preston equation. Based on the time-dependent model, we proposed a strategy to improve the RC-lap smoothing efficiency, which incorporated the theoretical model, tool optimization, and efficiency limit determination. Two sets of smoothing experiments were performed to demonstrate the smoothing efficiency achieved using the time-dependent smoothing model. A high, theory-like tool influence function and a limiting toolspeed of 300 RPM were obtained.
基金funding provided by the National Natural Science Foundation of China(Nos.62127901,6207031149 and11903035).
文摘Magnetorheological finishing(MRF)technology is widely used in the fabrication of high-precision optical elements.The material removal mechanism of MRF has not been fully understood because MRF technology involves the integration of electromagnetics,contact mechanics,and materials science.In this study,the rheological properties of the MR polishing fluid in oscillation model have been investigated.We propose that the shear-thinned MR polishing fluid over the polishing area should be considered a dense granular flow,based on which a new contact model of MRF over the polishing area has been constructed.Removal function and processing force test experiments were conducted under different working gaps.The normal pressure and effective friction equations over the polishing area were built based on the continuous medium and dense granular flow theories.Then,a novel MRF material removal model was established.A comparison of the results of the theoretical model with actual polishing results demonstrated the accuracy of the established model.The novel model proposed herein reveals the generation mechanism of shear force over a polished workpiece and realizes effective decoupling of the main processing parameters that influence the material removal of MRF.The results of this study will provide new and effective theoretical guidance for the process optimization and technology improvement of MRF.
基金supported by the National Natural Science Foundation of China(Nos.61675199,U1435210,61705226,61705224,aned 11604329).
文摘In common plasmonic structures,absorption and radiation losses are often mutually restricted and can seriously influence the device performance.The current study presents a compound structure composed of multilayer grating stripes and multilayer shallow trenches.A small depth was adopted for the trench configuration to exclude the extra bend loss.These two sections supported Fabry–Perot resonance and cavity modes,respectively,with hybrid modes formed through intercoupling.In addition,the total loss for the entire framework was clearly reduced due to the introduction of the trench geometry,indicating that both absorption and radiation losses were successfully taken into consideration in the compound structure.Significantly,such a low loss realized by the hybridization of surface plasmon polariton modes has rarely been seen before.Moreover,the debatable relationship between the total and partial quality factors was described for the first time based on a hybrid mode analysis to establish a new approach to investigate the different resonance modes.In the detailed calculation process,the relative electric field intensity was first adopted to stipulate the effective areas for the various modes,which is more reasonable than using the common definition that is based on a unit structure.The multilayer trench grating exhibited a relatively low loss without weakening energy localization,which is significant in the design of plasmonic devices.
基金supported by the National 973 Program of China(No.2011CB013205)the National Natural Science Foundation of China(No.51305422)
文摘The demand for space-borne telescopes with an aperture of 20 m is forcing the development of large diameter diffractive Fresnel zone lenses（FZLs） on membranes. However, due to the fabrication errors of multi-level microstructures, the real diffraction efficiency is always significantly smaller than the theoretical value. In this Letter,the effects of a set of fabrication errors on the diffraction efficiency for a diffractive membrane are studied. In order to verify the proposed models, a 4-level membrane FZL with a diameter of 320 mm is fabricated. The fabrication errors of the membrane FZL are measured, and its diffraction efficiency in the ＋1 order is also tested.The results show that the tested diffraction efficiency is very close to the calculated value based on the proposed models. It is expected that the present work could play a theoretical guiding role in the future development of space-borne diffractive telescopes.
