Frequency-doubled antireflection coatings simultaneously effective at 1064 nm and 532 nm were deposited on the lithium triborate （LiB3O5 or LBO） crystals using the electron beam evaporation method. Comparing with th...Frequency-doubled antireflection coatings simultaneously effective at 1064 nm and 532 nm were deposited on the lithium triborate （LiB3O5 or LBO） crystals using the electron beam evaporation method. Comparing with the sample without buffer layer, it is found that the adhesion of the sample with buffer layer of SiO2 between coating and LBO substrate is improved significantly from 137.4 mN to greater than 200 mN. And the laser-induced damage threshold is increased by 20% from 15.1 J/cm^2 to 18.6 J/cm^2. The strengthening mechanism of adhesion of the buffer layer of SiO2 is discussed by considering full plastic indentation and shear theory.展开更多
1 064 nm, 532 nm frequency-doubled antireflection （AR） coatings with buffer layer of SiO2 between the coating and the substrate were fabricated by the electron beam evaporation technology on the substrate of lithium...1 064 nm, 532 nm frequency-doubled antireflection （AR） coatings with buffer layer of SiO2 between the coating and the substrate were fabricated by the electron beam evaporation technology on the substrate of lithium triborate （LiB3O5 or LBO） crystals. The residual reflectance of the sample is 0.07% and 0.11% at 1 064 nm and 532 nm, respectively. The adhesion and the laser-induced damage threshold （LIDT） of the sample are greater than 200 mN and 18.6 J/cm2. The strengthening mechanism of adhesion and LIDT of the buffer layer of SiO2 were discussed by considering full plastic indentation and shear theory, and spallation of a plated film induced by thermal shock stress, respectively.展开更多
Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with co...Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with complex surfaces.Herein,by manipulating the interactions between block copolymers and selective solvents,we prepare repairable nanoporous polymers on arbitrary substrates.This is realized by an extremely simple sequential coating process:sequential coating of block copolymers and their swelling agents on substrate surfaces.The swelling agents are comprised of two solvents that swell the constituent blocks of the copolymers to different degrees,rapidly producing polymer coatings with uniform,interconnected,sub-50 nm pores.This sequential coating process is able to conformally build nanoporous polymers on nonplanar substrates with large lateral sizes and complex surface features,and also to in situ repair defects arising during usages.We further demonstrate that the nanoporous coatings show excellent antireflective and membrane separation performances.This sequential coating process is dictated by polymer–solvent interactions,and is expected to find applications in diverse fields for its simplicity,adaptability,and the capability to produce well-defined nanoporosities.展开更多
Almost half of the solar energy that reaches a silicon solar cell is lost due to the reflection at the silicon–air interface.Antireflective coatings aim to suppress the reflection and thereby to increase the photogen...Almost half of the solar energy that reaches a silicon solar cell is lost due to the reflection at the silicon–air interface.Antireflective coatings aim to suppress the reflection and thereby to increase the photogenerated current.The conventional few-layer dielectric antireflective coatings may significantly boost the transmission of solar light,but only in a narrow wavelength range.Using forward and inverse design optimization algorithms,we develop the designs of antireflective coatings for silicon solar cells based on single-layer silicon metasurfaces(periodic subwavelength nanostructure arrays),leading to a broadband reflection suppression in the wavelength range from 500 to 1200 nm for the incidence angles up to 60 deg.The reflection averaged over the visible and near-infrared spectra is at the record-low level of approximately 2%and 4.4%for the normal and oblique incidence,respectively.The obtained results demonstrate the potential of machine learning–enhanced photonic nanostructures to outperform the classical antireflective coatings.展开更多
Broadband and omnidirectional antireflection coating is generally an effective way to improve solar cell efficiency, because the destructive interference between the reflected and incident light can maximize the light...Broadband and omnidirectional antireflection coating is generally an effective way to improve solar cell efficiency, because the destructive interference between the reflected and incident light can maximize the light transmission into the absorption layer. In this paper, we report the incident quantum efficiency ηin, not incident energy or power, as the evaluation function by the ant colony algorithm optimization method, which is a swarm-based optimization method. Also, SPCTRL2 is proposed to be incorporated for accurate optimization because the solar irradiance on a receiver plane is dependent on position, season, and time. Cities of Quito, Beijing and Moscow are selected for two-and three-layer antireflective coating optimization over λ = [300,1100] nm and θ = [0°, 90°]. The ηin increases by 0.26%, 1.37% and 4.24% for the above 3 cities, respectively, compared with that calculated by other rigorous optimization algorithms methods, which is further verified by the effect of position and time dependent solar spectrum on the antireflective coating design.展开更多
We suggest a design method of graded-refractive-index （GRIN） antireflection （AR） coating for s-polarized or p- polarized light at off-normal incidence. The spectrum characteristic of the designed antireflection co...We suggest a design method of graded-refractive-index （GRIN） antireflection （AR） coating for s-polarized or p- polarized light at off-normal incidence. The spectrum characteristic of the designed antireflection coating with a quintic effective refractive-index profile for a given state of polarization has been discussed. In addition, the genetic algorithm was used to optimize the refractive index profile of the GRIN antireflection for reducing the mean reflectance of s- and p-polarizations. The average reflectance loss was reduced to only 0.04% by applying optimized GRIN AR coatings onto BK7 glass over the wavelength range from 400 to 800 nm at the incident angle of θo = 70°.展开更多
This paper reports that SiO2 is selected to fabricate broadband antireflection （AR） coatings on fused silica substrate by using glancing angle deposition and physical vapour deposition. Through accurate control of t...This paper reports that SiO2 is selected to fabricate broadband antireflection （AR） coatings on fused silica substrate by using glancing angle deposition and physical vapour deposition. Through accurate control of the graded index of the SiO2 layer, transmittance of thc graded broadband AR coating can achieve an average value of 98% across a spectral range of 300-1850 nm. Moreover, a laser-induced damage threshold measurement of the fabricated AR coating is performed by using a one-on-one protocol according to ISOl1254-1, resulting in an average damage threshold of 17.2 J/cm2.展开更多
Electro-optical/infrared (EO/IR) sensors and photovoltaic power sources are being developed for a variety of defense and commercial applications. One of the critical technologies that will enhance both EO/IR sensor an...Electro-optical/infrared (EO/IR) sensors and photovoltaic power sources are being developed for a variety of defense and commercial applications. One of the critical technologies that will enhance both EO/IR sensor and photovoltaic module performance is the development of high quality nanostructure-based antireflection coatings. In this paper, we review our work on advanced antireflection structures that have been designed by using a genetic algorithm and fabricated by using oblique angle deposition. The antireflection coatings are designed for the wavelength range of 250 nm to 2500 nm and an incidence angle between 00 and 400. These nanostructured antireflection coatings are shown to enhance the optical transmission through transparent windows over a wide band of interest and minimize broadband reflection losses to less than one percent, a substantial improvement over conventional thin-film antireflection coating technologies.展开更多
We reported a facile and bio-inspired strategy for obtaining antireflective （AR） coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different mo...We reported a facile and bio-inspired strategy for obtaining antireflective （AR） coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-cross- linking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5% ～ 8%, with an efficiency anti- reflection of 4% ～ 7%; compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4% ～ 8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern. Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle展开更多
In this paper, multilayer antireflection coatings are designed by modifying the thickness of two and three paired layer distributed Bragg reflector （DBR） structure. Our proposed DBR-based structures show antireflect...In this paper, multilayer antireflection coatings are designed by modifying the thickness of two and three paired layer distributed Bragg reflector （DBR） structure. Our proposed DBR-based structures show antireflection behaviors, in spite of the reflection treatment in traditional DBR structures. Firstly, the proposed structures are designed to be equivalent to the theoretical ideal triple-layer （TL） antireflection coating （ARC）. Therefore, the problem of finding a suitable material for the middle layer of triple structure is solved. Simulation results show the significant equivalency for the reflectance of proposed structures to the ideal TL ARC at the same wavelengths and incident angles. Also, the design of the structure is changed in order to present the constant reflectance coefficient over a wide range of wavelengths. This structure enhances the omni-directionality of the multilayer ARC.展开更多
The AR coatings for GaInP/GaAs tandem solar cell are simulated.Results show that,under the condition of the lack of suitable encapsulation, a very low energy loss could be reached on MgF2/ZnS system; in the case of gl...The AR coatings for GaInP/GaAs tandem solar cell are simulated.Results show that,under the condition of the lack of suitable encapsulation, a very low energy loss could be reached on MgF2/ZnS system; in the case of glass encapsulation,the Al2O3/ZrO2 and Al2O3/TiO2 systems are appropriate choice; for AlInP window layer,the thickness of 30 nm is suitable.展开更多
Refractive index inhomogeneity is one of the important characteristics of optical coating material, which is one of the key factors to produce loss to the ultra-low residual reflection coatings except using the refrac...Refractive index inhomogeneity is one of the important characteristics of optical coating material, which is one of the key factors to produce loss to the ultra-low residual reflection coatings except using the refractive index inhomogeneity to obtain gradient-index coating. In the normal structure of antireflection coatings for center wavelength at 532 nm, the physical thicknesses of layer H and layer L are 22.18 nm and 118.86 nm, respectively. The residual reflectance caused by refractive index inhomogeneity（the degree of inhomogeneous is between -0.2 and 0.2） is about 200 ppm, and the minimum reflectivity wavelength is between 528.2 nm and 535.2 nm. A new numerical method adding the refractive index inhomogeneity to the spectra calculation was proposed to design the laser antireflection coatings, which can achieve the design of antireflection coatings with ppm residual reflection by adjusting physical thickness of the couple layers. When the degree of refractive index inhomogeneity of the layer H and layer L is-0.08 and 0.05 respectively, the residual reflectance increase from zero to 0.0769% at 532 nm. According to the above accuracy numerical method, if layer H physical thickness increases by 1.30 nm and layer L decrease by 4.50 nm, residual reflectance of thin film will achieve to 2.06 ppm. When the degree of refractive index inhomogeneity of the layer H and layer L is 0.08 and -0.05 respectively, the residual reflectance increase from zero to 0.0784% at 532 nm. The residual reflectance of designed thin film can be reduced to 0.8 ppm by decreasing the layer H of 1.55 nm while increasing the layer L of 4.94 nm.展开更多
The superluminescent diode has been fabricated by applying an AR coating to the output facet of the semiconductor laser for the purpose of eliminating or suitably reducing the optical feedback. An exact method for mea...The superluminescent diode has been fabricated by applying an AR coating to the output facet of the semiconductor laser for the purpose of eliminating or suitably reducing the optical feedback. An exact method for measuring the modal reflectivity of the antireflection coating to a laser diode is described. It is based on measurements of the spectrum modulation depth of the resulting superluminescent diode output spectrum at arbitrary injection current, and modal reflectivity of less than 3 × 10-4 is obtained.展开更多
Surface plasmon enhanced antireflection coatings for GaAs solar cells have been designed theoretically.The reflectance of double-layer antireflection coatings（ARCs） with different suspensions of Ag particles is calc...Surface plasmon enhanced antireflection coatings for GaAs solar cells have been designed theoretically.The reflectance of double-layer antireflection coatings（ARCs） with different suspensions of Ag particles is calcu-lated as a function of the wavelength according to the optical interference matrix and the Mie theory.The mean dielectric concept was adopted in the simulations.A significant reduction of reflectance in the spectral region from 300 to 400 nm was found to be beneficial for the design of ARCs.A new SiO2/Ag-ZnS double-layer coating with better antireflection ability can be achieved if the particle volume fraction in ZnS is 1%-2%.展开更多
Near-field holography（NFH）, with its virtues of precise critical dimensions and high throughput, has a great potential for the realization of soft x-ray diffraction gratings. We show that NFH with reflections reduce...Near-field holography（NFH）, with its virtues of precise critical dimensions and high throughput, has a great potential for the realization of soft x-ray diffraction gratings. We show that NFH with reflections reduced by the integration of antireflective coatings（ARCs） simplifies the NFH process relative to that of setups using refractive index liquids. Based on the proposed NFH with ARCs, gold-coated laminar gratings were fabricated using NFH and subsequent ion beam etching. The efficiency angular spectrum shows that the stray light of the gratings is reduced one level of magnitude by the suppression of interface reflections during NFH.展开更多
Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer were investigated for LIB3O5 （LBO） substrate. The design was based on the vector method. The thickness of ...Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer were investigated for LIB3O5 （LBO） substrate. The design was based on the vector method. The thickness of the inserted SiO2 interlayer could be changed in a wide range for the four-layer design with two zeros at 1064 and 532 nm. The coatings without any interlayer and with 0.1 quarter-wave （λ/4）, 0.3 λ/4, 0.5 λ/4 SiO2 interlayer were deposited respectively on LBO by using electron beam evaporation technique. All the prepared coatings with SiO2 interlayer indicated satisfying optical behavior. This expanded our option for the thickness of an interlayer when coating on LBO substrate. The prepared films with SiO2 interlayer showed better adhesion than that without any interlayer. The thickness of the interlayer affected the adhesion, the adhesion for the coating with 0.5 λ/4 SiO2 interlayer was not as good as the other two.展开更多
To improve the optical performance of an antireflection（AR） coating on a micro-spherical substrate, the ray angle of the incidence distribution and the thickness profile are taken into consideration during the optic...To improve the optical performance of an antireflection（AR） coating on a micro-spherical substrate, the ray angle of the incidence distribution and the thickness profile are taken into consideration during the optical coating design. For a convex spherical substrate with a radius of curvature of 10 mm and a clear aperture of 10 mm,three strategies are used for the optimization of the spectral performance of a broadband AR coating in the spectral region from 480 to 720 nm. By comparing the calculated residual reflectance and spectral uniformity,the developed method demonstrates its superiority in spectral performance optimization of an AR coating on a micro-spherical substrate.展开更多
An antireflection （AR） coating is fabricated by applying an optimal spin-coating method and a pH-modified SiO2 nanoparticle solution on a cover glass. Because the pH value of the solution will affect the aggregation...An antireflection （AR） coating is fabricated by applying an optimal spin-coating method and a pH-modified SiO2 nanoparticle solution on a cover glass. Because the pH value of the solution will affect the aggregation and dispersion of the SiO2 particles, the transmittance of the AR-treated cover glass will be enhanced under optimal fabricated conditions. The experimental results show that an AR coating fabricated by an SiO2 nano- particle solution of pH 11 enhances the transmittance approximately by 3% and 5% under normal and oblique incident conditions, respectively. Furthermore, the AR-treated cover glass exhibits hydrophobicity and shows a 65% enhancement at a contact angle to bare glass.展开更多
We report a new structure for broadband antireflection coating by dip-coating technique, which has minimal cost and is compatible with large-scale manufacturing. The coatings are prepared by depositing SiO2 sol-gel fi...We report a new structure for broadband antireflection coating by dip-coating technique, which has minimal cost and is compatible with large-scale manufacturing. The coatings are prepared by depositing SiO2 sol-gel film on a glass substrate, subsequently depositing SiO2 single-layer particle coating through electrostatic attraction, and depositing a final very thin SiO2 sol-gel film to improve the mechanical strength of the whole coating structure. The refractive index of the structure changes gradually from the top to the substrate. The transmittance of a glass substrate has been experimentally found to be improved in the spectral range of 400-1 400 nm and in the incidence angle range from 0° to at least 45°. The mechanical strength is immensely improved because of the additional thin SiO2 sol-gel layer. The surface texture can be applied to the substrates of different materials and shapes as an add-on coating.展开更多
基金Fundeded by the Doctorial Start-up Fund of the Department of Science and Technology of Liaoning Province(20081030)S&T Plan Project of the Educational Department of Liaoning Province(2008224)
文摘Frequency-doubled antireflection coatings simultaneously effective at 1064 nm and 532 nm were deposited on the lithium triborate （LiB3O5 or LBO） crystals using the electron beam evaporation method. Comparing with the sample without buffer layer, it is found that the adhesion of the sample with buffer layer of SiO2 between coating and LBO substrate is improved significantly from 137.4 mN to greater than 200 mN. And the laser-induced damage threshold is increased by 20% from 15.1 J/cm^2 to 18.6 J/cm^2. The strengthening mechanism of adhesion of the buffer layer of SiO2 is discussed by considering full plastic indentation and shear theory.
基金Funded by the Doctorial Start-up Fund of the Department of Science and Technology of Liaoning Province (20081030)
文摘1 064 nm, 532 nm frequency-doubled antireflection （AR） coatings with buffer layer of SiO2 between the coating and the substrate were fabricated by the electron beam evaporation technology on the substrate of lithium triborate （LiB3O5 or LBO） crystals. The residual reflectance of the sample is 0.07% and 0.11% at 1 064 nm and 532 nm, respectively. The adhesion and the laser-induced damage threshold （LIDT） of the sample are greater than 200 mN and 18.6 J/cm2. The strengthening mechanism of adhesion and LIDT of the buffer layer of SiO2 were discussed by considering full plastic indentation and shear theory, and spallation of a plated film induced by thermal shock stress, respectively.
基金support from National Science Foundation of China(22438005)the Natural Science Foundation of Jiangsu Province(BE2022056-3)is gratefully acknowledged.
文摘Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with complex surfaces.Herein,by manipulating the interactions between block copolymers and selective solvents,we prepare repairable nanoporous polymers on arbitrary substrates.This is realized by an extremely simple sequential coating process:sequential coating of block copolymers and their swelling agents on substrate surfaces.The swelling agents are comprised of two solvents that swell the constituent blocks of the copolymers to different degrees,rapidly producing polymer coatings with uniform,interconnected,sub-50 nm pores.This sequential coating process is able to conformally build nanoporous polymers on nonplanar substrates with large lateral sizes and complex surface features,and also to in situ repair defects arising during usages.We further demonstrate that the nanoporous coatings show excellent antireflective and membrane separation performances.This sequential coating process is dictated by polymer–solvent interactions,and is expected to find applications in diverse fields for its simplicity,adaptability,and the capability to produce well-defined nanoporosities.
基金support of the U.S.Civilian Research and Development Foundation“CRDF Global”(Grant No.G-202401-71609)。
文摘Almost half of the solar energy that reaches a silicon solar cell is lost due to the reflection at the silicon–air interface.Antireflective coatings aim to suppress the reflection and thereby to increase the photogenerated current.The conventional few-layer dielectric antireflective coatings may significantly boost the transmission of solar light,but only in a narrow wavelength range.Using forward and inverse design optimization algorithms,we develop the designs of antireflective coatings for silicon solar cells based on single-layer silicon metasurfaces(periodic subwavelength nanostructure arrays),leading to a broadband reflection suppression in the wavelength range from 500 to 1200 nm for the incidence angles up to 60 deg.The reflection averaged over the visible and near-infrared spectra is at the record-low level of approximately 2%and 4.4%for the normal and oblique incidence,respectively.The obtained results demonstrate the potential of machine learning–enhanced photonic nanostructures to outperform the classical antireflective coatings.
基金supported by the National Key Research and Development of China (No. 2017YFF0104801)the National Natural Science Foundation of China (Nos. 61675046, 61804012)the Open Fund of IPOC (No. IPOC2017B011)
文摘Broadband and omnidirectional antireflection coating is generally an effective way to improve solar cell efficiency, because the destructive interference between the reflected and incident light can maximize the light transmission into the absorption layer. In this paper, we report the incident quantum efficiency ηin, not incident energy or power, as the evaluation function by the ant colony algorithm optimization method, which is a swarm-based optimization method. Also, SPCTRL2 is proposed to be incorporated for accurate optimization because the solar irradiance on a receiver plane is dependent on position, season, and time. Cities of Quito, Beijing and Moscow are selected for two-and three-layer antireflective coating optimization over λ = [300,1100] nm and θ = [0°, 90°]. The ηin increases by 0.26%, 1.37% and 4.24% for the above 3 cities, respectively, compared with that calculated by other rigorous optimization algorithms methods, which is further verified by the effect of position and time dependent solar spectrum on the antireflective coating design.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10704079 and 10976030)
文摘We suggest a design method of graded-refractive-index （GRIN） antireflection （AR） coating for s-polarized or p- polarized light at off-normal incidence. The spectrum characteristic of the designed antireflection coating with a quintic effective refractive-index profile for a given state of polarization has been discussed. In addition, the genetic algorithm was used to optimize the refractive index profile of the GRIN antireflection for reducing the mean reflectance of s- and p-polarizations. The average reflectance loss was reduced to only 0.04% by applying optimized GRIN AR coatings onto BK7 glass over the wavelength range from 400 to 800 nm at the incident angle of θo = 70°.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10804060)Higher Educational Science and Technology Program of Shandong Province of China (Grant No. J08LI05)
文摘This paper reports that SiO2 is selected to fabricate broadband antireflection （AR） coatings on fused silica substrate by using glancing angle deposition and physical vapour deposition. Through accurate control of the graded index of the SiO2 layer, transmittance of thc graded broadband AR coating can achieve an average value of 98% across a spectral range of 300-1850 nm. Moreover, a laser-induced damage threshold measurement of the fabricated AR coating is performed by using a one-on-one protocol according to ISOl1254-1, resulting in an average damage threshold of 17.2 J/cm2.
文摘Electro-optical/infrared (EO/IR) sensors and photovoltaic power sources are being developed for a variety of defense and commercial applications. One of the critical technologies that will enhance both EO/IR sensor and photovoltaic module performance is the development of high quality nanostructure-based antireflection coatings. In this paper, we review our work on advanced antireflection structures that have been designed by using a genetic algorithm and fabricated by using oblique angle deposition. The antireflection coatings are designed for the wavelength range of 250 nm to 2500 nm and an incidence angle between 00 and 400. These nanostructured antireflection coatings are shown to enhance the optical transmission through transparent windows over a wide band of interest and minimize broadband reflection losses to less than one percent, a substantial improvement over conventional thin-film antireflection coating technologies.
基金the National Natural Science Foundation of China (Nos. 21522403, 51373098)the National Basic Research Program (No. 2013CB834506)+1 种基金Education Commission of Shanghai Municipal Government (No. 15SG13)IFPM 2016B002 of Shanghai Jiao Tong University & Affiliated Sixth People’s Hospital South Campus for their financial support
文摘We reported a facile and bio-inspired strategy for obtaining antireflective （AR） coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-cross- linking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5% ～ 8%, with an efficiency anti- reflection of 4% ～ 7%; compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4% ～ 8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern. Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle
文摘In this paper, multilayer antireflection coatings are designed by modifying the thickness of two and three paired layer distributed Bragg reflector （DBR） structure. Our proposed DBR-based structures show antireflection behaviors, in spite of the reflection treatment in traditional DBR structures. Firstly, the proposed structures are designed to be equivalent to the theoretical ideal triple-layer （TL） antireflection coating （ARC）. Therefore, the problem of finding a suitable material for the middle layer of triple structure is solved. Simulation results show the significant equivalency for the reflectance of proposed structures to the ideal TL ARC at the same wavelengths and incident angles. Also, the design of the structure is changed in order to present the constant reflectance coefficient over a wide range of wavelengths. This structure enhances the omni-directionality of the multilayer ARC.
文摘The AR coatings for GaInP/GaAs tandem solar cell are simulated.Results show that,under the condition of the lack of suitable encapsulation, a very low energy loss could be reached on MgF2/ZnS system; in the case of glass encapsulation,the Al2O3/ZrO2 and Al2O3/TiO2 systems are appropriate choice; for AlInP window layer,the thickness of 30 nm is suitable.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61405145 and 61235011)the Natural Science Foundation of Tianjin,China(Grant No.15JCZDJC31900)the China Postdoctoral Science Foundation(Grant Nos.2015T80115 and 2014M560104)
文摘Refractive index inhomogeneity is one of the important characteristics of optical coating material, which is one of the key factors to produce loss to the ultra-low residual reflection coatings except using the refractive index inhomogeneity to obtain gradient-index coating. In the normal structure of antireflection coatings for center wavelength at 532 nm, the physical thicknesses of layer H and layer L are 22.18 nm and 118.86 nm, respectively. The residual reflectance caused by refractive index inhomogeneity（the degree of inhomogeneous is between -0.2 and 0.2） is about 200 ppm, and the minimum reflectivity wavelength is between 528.2 nm and 535.2 nm. A new numerical method adding the refractive index inhomogeneity to the spectra calculation was proposed to design the laser antireflection coatings, which can achieve the design of antireflection coatings with ppm residual reflection by adjusting physical thickness of the couple layers. When the degree of refractive index inhomogeneity of the layer H and layer L is-0.08 and 0.05 respectively, the residual reflectance increase from zero to 0.0769% at 532 nm. According to the above accuracy numerical method, if layer H physical thickness increases by 1.30 nm and layer L decrease by 4.50 nm, residual reflectance of thin film will achieve to 2.06 ppm. When the degree of refractive index inhomogeneity of the layer H and layer L is 0.08 and -0.05 respectively, the residual reflectance increase from zero to 0.0784% at 532 nm. The residual reflectance of designed thin film can be reduced to 0.8 ppm by decreasing the layer H of 1.55 nm while increasing the layer L of 4.94 nm.
文摘The superluminescent diode has been fabricated by applying an AR coating to the output facet of the semiconductor laser for the purpose of eliminating or suitably reducing the optical feedback. An exact method for measuring the modal reflectivity of the antireflection coating to a laser diode is described. It is based on measurements of the spectrum modulation depth of the resulting superluminescent diode output spectrum at arbitrary injection current, and modal reflectivity of less than 3 × 10-4 is obtained.
文摘Surface plasmon enhanced antireflection coatings for GaAs solar cells have been designed theoretically.The reflectance of double-layer antireflection coatings（ARCs） with different suspensions of Ag particles is calcu-lated as a function of the wavelength according to the optical interference matrix and the Mie theory.The mean dielectric concept was adopted in the simulations.A significant reduction of reflectance in the spectral region from 300 to 400 nm was found to be beneficial for the design of ARCs.A new SiO2/Ag-ZnS double-layer coating with better antireflection ability can be achieved if the particle volume fraction in ZnS is 1%-2%.
基金supported by the Sino-German Center for Research Promotion (No.GZ 983)the German Science Foundation DFG (No.IRTG 2101)+1 种基金the Joint Fund of the National Natural Science Foundation of Chinathe China Academy of Engineering Physics (No.U1230104)
文摘Near-field holography（NFH）, with its virtues of precise critical dimensions and high throughput, has a great potential for the realization of soft x-ray diffraction gratings. We show that NFH with reflections reduced by the integration of antireflective coatings（ARCs） simplifies the NFH process relative to that of setups using refractive index liquids. Based on the proposed NFH with ARCs, gold-coated laminar gratings were fabricated using NFH and subsequent ion beam etching. The efficiency angular spectrum shows that the stray light of the gratings is reduced one level of magnitude by the suppression of interface reflections during NFH.
文摘Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer were investigated for LIB3O5 （LBO） substrate. The design was based on the vector method. The thickness of the inserted SiO2 interlayer could be changed in a wide range for the four-layer design with two zeros at 1064 and 532 nm. The coatings without any interlayer and with 0.1 quarter-wave （λ/4）, 0.3 λ/4, 0.5 λ/4 SiO2 interlayer were deposited respectively on LBO by using electron beam evaporation technique. All the prepared coatings with SiO2 interlayer indicated satisfying optical behavior. This expanded our option for the thickness of an interlayer when coating on LBO substrate. The prepared films with SiO2 interlayer showed better adhesion than that without any interlayer. The thickness of the interlayer affected the adhesion, the adhesion for the coating with 0.5 λ/4 SiO2 interlayer was not as good as the other two.
文摘To improve the optical performance of an antireflection（AR） coating on a micro-spherical substrate, the ray angle of the incidence distribution and the thickness profile are taken into consideration during the optical coating design. For a convex spherical substrate with a radius of curvature of 10 mm and a clear aperture of 10 mm,three strategies are used for the optimization of the spectral performance of a broadband AR coating in the spectral region from 480 to 720 nm. By comparing the calculated residual reflectance and spectral uniformity,the developed method demonstrates its superiority in spectral performance optimization of an AR coating on a micro-spherical substrate.
基金financially supporting this research under Contract No. NSC 102-2221-E-155-076-MY3
文摘An antireflection （AR） coating is fabricated by applying an optimal spin-coating method and a pH-modified SiO2 nanoparticle solution on a cover glass. Because the pH value of the solution will affect the aggregation and dispersion of the SiO2 particles, the transmittance of the AR-treated cover glass will be enhanced under optimal fabricated conditions. The experimental results show that an AR coating fabricated by an SiO2 nano- particle solution of pH 11 enhances the transmittance approximately by 3% and 5% under normal and oblique incident conditions, respectively. Furthermore, the AR-treated cover glass exhibits hydrophobicity and shows a 65% enhancement at a contact angle to bare glass.
文摘We report a new structure for broadband antireflection coating by dip-coating technique, which has minimal cost and is compatible with large-scale manufacturing. The coatings are prepared by depositing SiO2 sol-gel film on a glass substrate, subsequently depositing SiO2 single-layer particle coating through electrostatic attraction, and depositing a final very thin SiO2 sol-gel film to improve the mechanical strength of the whole coating structure. The refractive index of the structure changes gradually from the top to the substrate. The transmittance of a glass substrate has been experimentally found to be improved in the spectral range of 400-1 400 nm and in the incidence angle range from 0° to at least 45°. The mechanical strength is immensely improved because of the additional thin SiO2 sol-gel layer. The surface texture can be applied to the substrates of different materials and shapes as an add-on coating.
