This PDF file contains the front matter associated with SPIE Proceedings Volume 11064, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

Silicon carbide has good physical, mechanical and thermal properties, it has been widely used in aerospace field in recent years. In order to meet the requirements of optical performance of space remote sensor, silicon carbide surface is usually treated by surface modification technology for further implement requirements, this process is called modification. There are two ways of modification: PVD and CVD, the purpose is to cover the surface voids of silicon carbide with a modified layer, reducing surface roughness and suppression of surface scattering, improving imaging quality of optical system, improvement of resolution, reducing the loss of light energy .Now, modification technology is mature, but there are still risks in the modification process, there are also corresponding processing risks in the optical polishing process after modification. In order to investigate the influence to pitted reaction bonded SiC (RB-SiC) without SiC or Si cladding layer, 10nmCr, 10nmTi, 10nmGe and100nm Ag films are deposited using thermal evaporation method. The research results show that Ge can decrease the roughness of RB-SiC surface and has preferable smoothing effect of silver thin film comparing to that of Cr and Ti. This article through the research, a method of direct application of non-modified silicon carbide substrates in production practice is explored. The essence is to utilize the growth characteristics of materials, complete growth in the hole, achieve the purpose of filling holes, then the surface roughness is reduced and the surface scattering is suppressed.

Due to the interesting phase transition properties, Vanadium dioxide is a promising materials for smart windows. But phase transition temperature of 68° is high for this application. Doping is an useful method for transition temperature reducing in previous works. In this paper, different thickness VO₂ films were prepared by reactive pulsed magnetron sputtering, and a novel doping method was employed to reduce transition temperature. The results of XRD, Raman, transmittance spectra, and thermal hysteresis reveal that the transition temperature of un-doped samples is about 54~58°, and the increasing of phase transition amplitude and optical transmittance in visible decreasing with film thickness was observed. While for doped samples, all the transition temperatures reduced below 37°. For the thin thickness 12.5nm and 25nm, which phase transition performance deteriorated seriously. The thickness 25nm deposited for 1.5 h has the optimal performance of high optical transmittance and high IR adjustment ability.

Thin films have been widely used, and their preparation methods are varied. In this paper, a new type of hot pressing process is introduced to fabricate silicon dioxide thin films based on PET. The thickness of the prepared silica film is up to 40 microns, and the film is transparent. The SiO₂ thin films were deposited uniformly on Polyethylene terephthalate (PET) without obvious cracks, and the films could also be crimped. The prepared silicon dioxide films have the ability of passive radiative cooling, that is, the temperature of the films can reduce to lower than that of the ambient air. It can be expected that this method is also suitable for the preparation of other thin films.

The effective optical constants of fishnet metamaterial are affected by the surrounding dielectric material or layers Analytical formulas were derived to retrieve the effective optical constants of fishnet metamaterial surrounded by different bulk materials, from reflection and transmission coefficients, and the effective optical constants of the fishnet embedded in thin film layers stack were retrieved numerically. With increase of the refractive index of the surrounding dielectric material as well as of the thickness of the nearby dielectric layers, the plasmonic resonance spectral position undergoes redshift while the absolute maximum value of negative refractive index of fishnet decreases.

In this work the optical and electrical characteristics of radio frequency sputtered indium tin oxide (ITO), aluminum doped zinc oxide (AZO) and nickel oxide (NiOx) are reported. ITO and AZO films showed very high visible transmittance values, with maxima up to 90-91%, and sheet resistance of 35 and 33 Ω/□, respectively, while non stoichiometric NiO films showed visible transmittance up to 53% and sheet resistance of several tens of KΩ/□. Properties of the films were correlated to their structure and morphology which are strongly dependent on the growth parameters.

An optical material WS₂ thin film on SiC substrate was synthesized. Both 15nm and 150nm thickness of WS² films were deposited on a n-doped SiC substrate by pulsed laser deposition (PLD) method. Tungsten disulfide films were superimposed face to face, and silicon carbide was used as the electrode to apply an electric field ranging from 0V/nm to 0.18v /nm. The experimental results showed that band gap were continuously tunable from 2.017ev to 1.507ev. The first principle calculation by using Quantum Espresso also was performed to simulate the band gap change with the increase of an external electric field. It is found that the band gap of WS2/SiC film changes from 1.973ev to 1.488ev as an electric field applied perpendicularly to the film ranging from 0V/nm to 0.18v /nm. The consistency of experimental results and the first principle calculation was found.

In order to obtain high-performance short-mid infrared anti-reflection membrane, Si, SiO, and MgF₂ are used to design the system structure, in which MgF₂ is located in the outermost layer and expose in the atmosphere. However, due to the porous structure of fluoride thin film, the peaking density of MgF₂ film is low, which is prone to the moisture absorbing. The water vapor comes into the film not only caused the transmittance decrease but also lead to the poor adhesion. The excessive power of ion source assisted deposition increases the stress of MgF₂ film, resulting in the stress mismatch between MgF₂ film and the previous Si layer, caused the MgF₂ film cracks. To improve the adhesion of the film, this paper invests a way to matching stress by plating bond layer between MgF₂ and Si, and adopts the step annealing process combined with ion beam assisted deposition to improve the film aggregation density and decrease the absorption of water vapor, and further reduce the film stress. The spectral transmittance of prepared films is greater than 96% in1.5~5μm. After 7 days, the spectral transmittance decreased by only 0.6% and remained stable for the next 30 days. The prepared film with high quality can through 10 times adhesive test without fracture.

In a previous study, the temperature-rise of a spectral beam combining grating was analyzed theoretically and experimentally. It was concluded that the temperature of a grating can be effectively reduced by increasing the substrate thickness or by using a substrate material with higher thermal conductivity. In this study, yttrium aluminum garnet (YAG) was used as the substrate material to fabricate a spectral beam combining grating. The temperature, distortion, and far-field beam quality of the YAG-substrate-grating were analyzed theoretically and experimentally. It is concluded that, compared with the traditional quartz-substrate-grating, not only can the YAG-substrate-MDG withstand higher power, but the beam quality of the diffraction laser is also better.

Nanowire solar cells are of great interests due to their promising prospects as nano-electronic power sources. Here, we propose a standing semiconductor-dielectric core-shell nanocone array (CSNCA). We find that the CSNCA structure can not only concentrate the incident light into the structure, but also confine most of the concentrated light to the semiconductor (InP) core region, which enhances remarkably the light absorption of the more material-saving semiconductor core. Thanks to the gradient of diameter size along the axial in cone, incident light of different wavelengths can be maximally coupled into the core. We find guided resonance features along the radial and FP-resonant features along the axial by analyzing the electric field patterns at the absorption spectrum peaks. The CSNCA can support multiple higherorder HE modes, in comparison to the bare nanocone array (BNCA). Interaction of the adjacent higher-order HE modes results in broadband light absorption enhancement in the solar radiation spectrum. Carrier generation rates (G) have also been studied when the electrical part is discussed. CSNCAs show a unique advantage in G distribution. Results based on detailed balance analysis demonstrate that the core-shell design gives rise to higher short-circuit current and open-circuit voltage, and thus higher power conversion efficiency. This advantage is more apparent in thin structures compared with the thick ones. Detailed research is focused on the 1 μm high CSNCAs, and a remarkable enhancement (42.2%) is gained compared with the BNCAs. Our study shows that the CSNCAs can be promising candidates for application in super miniature photodetectors, nanometer power sources and ultra-thin film solar cells.

Currently, unidirectional energy flow films mainly rely on surface plasma polarization and photonic crystals, their working bands are narrow and they are mainly used in the field of optical communication. This paper simulates and optimizes an optical array film attached with a large number of micro hemispheres. When the parallel incident light is incident from the inner side of the film (A side) to the outer side (B side), most of the incident light can pass through the film to the outer side at different angles; when the parallel incident light is incident from the outer side to the inner side, a considerable portion of the incident light returns to the outer side when the incident angles are larger than 60°. Therefore, the film will generate energy flow difference. Although the energy flow difference cannot reach 100%, the working band of the film is relatively broad. In this paper, the height and refractive index of the micro hemisphere are continuously optimized, and the maximum energy flow difference reaches up to 97.5% at the angle of 80° eventually.

Laser heat-mode lithography is very useful for the fabrication of micro/nanostructure-based optical elements. In laser heat-mode lithography, the pattern structures need to be transferred to the substrates by wet-etching or dry-etching method. In this work, a lift-off method for the pattern transfer in laser heat-mode lithography was proposed and studied. A desirable undercut profile was obtained by manipulating the thermal field profile of laser heat-mode exposure, and a lift-off of Cr layer with a thickness of 80 nm on a quartz glass substrate was achieved. The results indicated that laser heat-mode lithography with lift-off process is an effective method to transfer the pattern structures to Cr layer and generate a Cr-based hard mask, which is useful for the fabrication of micro/nanostructure-based optical elements.

The GeSbTe (GST) thin films are usually used as optical and electronic data recording materials. In this work, the GST thin films were used as both negative and positive resists, and the positive and negative tone pattern structures were fabricated on the GST thin films, accordingly. The GST films were first deposited on the substrate, then the laser exposures were conducted through a focused laser beam spot. For negative resist, a Tetramethyl ammonium hydroxide (TMAH) was used as developing solution. For positive resist, (NH₄)₂S was used as developing solution. The structure heights of positive and negative resists are 53 nm and 180 nm were obtained, respectively. This work provides an effective method for fabricating the micro/nanostructures of optical and electronic elements.

Nowadays, optical elements are often shared in order to improve compactness of optical system and edge filter is one of the core parts. For same spectral system, when half convergence light incidents on edge filter, Sagittal and meridian will have different incident angle range, which cause different polarization characterization for the two directions and is harmful to the optical system’ MTF. In order to improve image quality, all factors affecting MTF are analyzed. When light incidents on edge filter, the difference between P and S polarization’s reflection phase can cause MTF drop. The design process of edge filter is optimized. Optical spectrum and reflection phase are optimized together. The variation is kept in a certain range for reflection phase of P and S polarization when edge filer attains spectrum requirement. The newly designed edge filter is sticked to optical system and carried out simulation. The calculation results showed that the newly designed edge filter has little effect on MTF. Ion-assisted e-beam evaporation method is used to deposit edge filter multilayer and the measurement result is in good accordance with that of the design. We think that a new design method is raised for design wide-incident angle and low polarization aberration edge filter.

Subwavelength periodic nanostructures on metal, dielectric or metal-dielectric-metal coating were fabricated by femtosecond laser. Circular apertures with diameter of ~0.6μm and a lattice period of 1.0 and 2.0 um were fabricated by single laser pulse irradiation. Surface geometries of nanostructure unit on the three kinds of coatings were compared using the scanning electron microscope and atomic force microscope. Moreover, the nanostructure units fabricated by front-side ablation technique and back-side ablation technique were compared. The minimum diameter of the circular aperture fabricated both by front-side ablation technique and back-side ablation technique could reach approximate 300 nm. By studying mechanisms of femtosecond laser interaction with metal films and dielectric films, it’s found that metal layers dominate femtosecond laser interaction with metal-dielectric-metal sandwich type coatings. It’s also found that the edges of apertures fabricated by back-side ablation technique in metal coatings and metal-dielectric-metal coatings are more regular and round than those fabricated by front-side ablation technique. Femtosecond laser fabrication therefore provides possibilities for maskless and speedy fabrication of fishnet structures which exhibit negative refractive index at optical frequencies.

A new doping approach of preparing VO₂ film was proposed to significantly tune the transition phase temperature. The heavy Ni-Cr-codoped VO₂ film ultra-thin layer was deposited on the pure VO₂ film by reactive pulsed magnetron sputtering on the Si substrate followed with annealing. The microstructure, optical and phase transition performance of VO₂ films were characterized via X-ray diffraction, UV/VIS/NIR spectrophotometer and thin film phase transition measurement system, respectively. The result indicates that the transition phase temperature of VO₂ film can be reduced from 53 ℃ to 30 ℃ by easily controlling different doping time.

Titanium dioxide (TiO₂) thin films have been receiving much attention in the past as their chemical stability and high refractive index. In this paper, TiO₂ thin films were prepared on fused silica substrates by ion beam sputtering technique and then are annealed at different temperature. The effects of the annealing temperature on the optical and structural properties of TiO₂ thin films were studied. The results show that the refractive index, extinction coefficient of the TiO₂ thin film decrease with the increase of annealing temperature. When the annealing temperature is higher than 350°C, the surface of TiO₂ thin films shows an uneven mesh crack, which forms a significant film damage. The experimental results indicated that thermal treatment can effectively change the optical properties of the TiO₂ thin films.

In this work, a chirped volume Bragg grating (CVBG) with over 40 nm high efficiency broadband spectra for pulse compression of near 100 fs was studied. Based on the fundamental matrix method, the effects of various structural parameters of CVBG on its diffraction characteristics were analyzed and then a design of broadband and high efficiency CVBG was proposed. Afterward, the monolithic CVBG was utilized to stretch and recompress a 100 fs pulse with a center wavelength of 1030 nm. The result shows this device has a high diffraction efficiency (84%) and a fine reciprocity. For the fabrication of large-size broadband CVBGs, double cylindrical wave holographic interference in photo-thermorefractive (PTR) glass was applied to achieve a wide range uniform and stable light field, which could greatly minimize unnecessary space chirp.

We design a broadband polarization beam splitter (PBS) operating in the terahertz (THz) communication band 0.1THz-1.2THz. The transmittance of the TM mode is larger than 95%, in the meanwhile, the extinction ratio can even reach 49dB. Considering the unavoidable deformation in grating fabrication, we also check the performance of the PBS based on trapeziform grating. Results show that increasing the duty cycle while the slope angle diminishing can effectively increase the TM mode transmittance and the extinction ratio, which can compensate the affection induced by the geometric deformation. This design may achieve some potential applications in THz manipulation system.

Polyimide films are widely used in spacecraft, but their mechanical properties would degrade in space environments, such as electron, proton, near ultraviolet or far ultraviolet, etc. The mechanical property and mechanism of polyimide film in electron, proton, near ultraviolet and far ultraviolet was studied by Φ800 combined space radiation test facility of Beijing Institute of Space Environment Engineering (BISSE), and the degradation of mechanical property of polyimide film was tested by Electronic tensile testing machine. The tensile strength and the rupture elongation of PI film decrease with the increase of electron and proton radiation, while tensile strength and the rupture elongation of PI film decrease firstly and then increase with near ultraviolet and far ultraviolet.

HfO² thin films were evaporated with ion beam assistance to achieve dense, homogeneous, stoichiometric and low-stress films. The ion beam energy were related to the optical and structural properties of the film. The absorption coefficient and the refractive index were measured by spectrophotometric technique while the microstructure has been studied by means of x-ray diffraction and atomic force microscopy. The correlation between the structure, optical properties and laser damage threshold were analyzed. The results suggest the HfO₂ structure and laser damage properties are closely related to the momentum transfer process during film deposition.

This work aims to design and fabricate sub-wavelength structures on lithium triborate surface for increasing its transmittance at 1064 nm. The finite-difference time-domain (FDTD) method is used to discuss the effects of subwavelength structure parameters such as period, depth, duty cycle and shape factor on the reflectivity. The subwavelength surface microstructures are fabricated by interference lithography technique and reactive ion beam etching method. The transmittance of the lithium triborate with single-side sub-wavelength structures is measured by UVvisible- near-infrared spectrophotometer. The results show that the transmittance of the sample with single-side microstructures at 1064 nm is about 4% higher than that of the polished substrate.

The design of a ZnSe-based linear polarizer operating in 3-13 μm broad infrared region with multilayer nanograting structures is performed. The multilayer nanograting structure is formed by a dielectric nanograting that is etched into ZnSe substrate, followed by metal/dielectric/metal thin film structure that are evaporated successively on the top and bottom of the ZnSe dielectric nanograting. An optical cavity is formed on both top and bottom of the ZnSe dielectric nanograting. Polarization characteristics of the proposed polarizer on structural parameters are investigated and an optimized multilayer structure is obtained. An extinction ratio (ER) of higher than 74 dB and TM-transmission (TMT) of averagely higher than 84% in the whole 3-13 μm broad waveband are obtained with a 250-nm-period multilayer nanograting. The ZnSe-based multilayer structure shows the possibility of achieving wide-band and high-performance polarization in 3-13 μm infrared region in a fashion of relatively easy-fabrication, in which no ion etching process is needed for the formation of metallic nanogratings.

High reflectivity of mirrors is very important for many applications in the vacuum ultraviolet, such as for space observation, synchrotron radiation. This paper focuses on the substrate temperature’s effect on the performance of Al mirrors when depositing the upper MgF₂ layer. Al films are deposited on the substrates at room temperature by thermal evaporation, and a 5 nm MgF₂ film is deposited on Al coating at room temperature immediately. Heating the substrate to various temperatures ranging from room temperature to 350°, then a 20 nm MgF₂ film is deposited on the surface of Al/MgF₂. The thickness of each layer is characterized using grazing incidence x-ray reflectivity. The reflectivity of sample is measured at the incident angle of 5° in the wavelength range of 105~130 nm. The reflectivity of all samples fabricated at above room temperature is higher than the sample at room temperature below 115nm. The reflectivity of mirror at 350° temperature is lower than other mirrors, and the reflectivity of the samples at 300° and 200° is similar. There are more black dots on the surface of mirror at 350° than 300°, and no black dot on the surface of mirror at 200°. The measured results using surface profiler show that the black dots are small holes that increase the roughness of mirror and reduce the reflectivity. So the best temperature for depositing the upper MgF₂ layer is in 200~300° to obtain high reflectivity of Al mirrors in vacuum ultraviolet.

The windows for the aerospace ship application is consist of fused silica and optical-films which can resist the ray-irradiation among the cosmos. For the optical-films produced by RF magnetron sputtering, the ray-irradiation anti-resist character is related with the sputtering temperature and the annealing temperature. As one of the high refractive index materials for the optical-design of the multi-layer optical film, CeO_x film were exposed to Co⁶⁰ irradiation of 10⁷ 、10⁸ 、and10⁹rad(Si) respectively. The spectrum- transmission line showed the optical character before and after the irradiation. Due to the decreasing of the defect among the film with the raising of the temperature ,the higher the sputtering and annealing temperature, the well anti-irradiation character. The transform of the Ce³⁺ and Ce4⁺ is beneficial for the optical character while the E^’ center can be moved from the visible-band to the ultraviolet band. But with the raising of the irradiation does, the micro-structure is key for the anti-irradiation character of the CeO_x film.

Ta₂O₅ film has low absorption in the range of visible wavelength and it has high refractive index and thermal stability. So it is widely used to prepare low loss films. Ta₂O₅ single layer with different oxygen flow rates were prepared by ion beam sputtering technique. The refractive index and absorption characteristics of metal oxide films were compared at different oxygen flow rates. The refractive index and absorption of thin film materials were studied by ellipsometry technology and surface thermal lens technology. The results show that: the absorption of Ta₂O₅ film is decreased first and then increased with the increase of oxygen flow. When oxygen flow is 40 sccm, the absorption is smallest, only 4.4ppm. And the refractive index is decreased with oxygen flow increasing, after oxygen flow reached 40 sccm, the refractive index tend to be stable.

Since negative photoresist SU-8 has become a common material for multi-photon micro-lithology, it is necessary to study laser conditions adopted in lithology process. Optical transmittance of SU-8 was tested. According to Urbach optical-absorption theory and Gaussian laser lateral spatial intensity envelope, relationship between theory and actual polymerization size of SU-8 was shown. Experimentally, we investigated multi-photon polymerization threshold and laser-induced damage of SU-8 under femtosecond laser irradiation with the pulse width of 45 fs at 800 nm by 1-on-1 tests. The polymerization and damage threshold at 45 fs are 2.7 and 8.9 TW/cm², respectively. Polymerization and damage morphologies are shown with high contrast and polymerization sizes are measured under SEM. Theoretical polymerization sizes versus laser fluence are calculated by laser-induce multi-photon polymerization size analysis (LMPSA), including Urbach optical-absorption theory and Gaussian laser lateral spatial intensity distribution. The calculated results show that diffusion exists in the femtosecond laser-induced polymerization.

Optical second surface reflector (OSR) is widely used as thermal control coating on the surface of spacecraft. Besides its thermal physics property such as solar absorption and thermal emissivity, its electrical property such as surface resistivity is used to prevent surface charging. Under the influence of space radiation environment, the surface electrical performance of OSR secondary surface mirror will be degraded, which will threaten the on-orbit safety and reliability of spacecraft. Based on the principle of dose depth distribution equivalence and total exposure equivalence, the influence of the space electron, proton and ultraviolet radiation environments on the surface electrical properties of OSR are experimentally studied, and its performance is in situ test. It was found that the resistivity of OSR secondary surface decreased exponentially with the increase of ultraviolet exposure and irradiation of electrons and protons. This shows that the surface conductivity of the OSR secondary surface mirror in space radiation environment increases and it has a better ability to resist surface charging and discharging effects.

In the field of complex optical systems, erbium doped fiber ring laser(EDFRL) is a kind of imperative fiber laser. Hundreds and thousands of longitudinal modes can typically coexist in this laser system, exhibiting nonlinear mode dynamics such as complex mode hopping and high-dimensional chaos. In this paper, dynamical output in free-running multi-longitudinal mode(MLM) EDFRL has been investigated experimentally and simulated numerically. Method to obtain real-time frequency and temporal intensity dynamics in group of dense individual longitudinal modes around central wavelength 1546.767nm is based on heterodyne detection, the utilized beat signal is generated by optical interference of adopted laser and reference laser. Frequency dynamics and time evolutions of heterodyne signal can be recorded by a radio frequency analyzer and fall graph. According to the experimental results, the output of MLM EDFRL mode dynamics is detected and the analysis for mode intensity can be obtained. Trying to simulate and explain the experimental observations, MLM laser model based on the saturable absorption of ions and ion-pairs in the gain medium, together with cross-coupling operation of corresponding longitudinal modes, has been discussed. The MLM laser model can effectively describe the individual behavior and clustering behavior of a large number of longitudinal modes, and reproduce theoretically the multi-mode dynamics of EDFRL system in frequency domain.

Carbon materials for dye-sensitized solar cells (DSSC) have aroused much attention recently due to their low cost, wonderful chemical stability and outstanding catalytic activity, etc. As China is a large agricultural country, in consideration of environmental protection and low cost, two common green vegetables, including cucumber and green pepper, are employed to prepare carbon quantum dots (CQD) by hydrothermal method, and simultaneously the residues are carbonized to obtain carbon particles (CP) in this study. The optical performances of the as-prepared CQD were acquired through UV-Vis and PL tests, showing that the CQD were suitable as sensitizers for DSSC. Thereby CQDbased DSSC with Pt counter electrode (CE) were experimentally fabricated, yielding the power conversion efficiency (PCE) of 0.21% and 0.28% respectively under AM 1.5 one sun illumination. Meanwhile, the CP were coated on FTO as CE for DSSC, and the favorable electrochemical properties of the CP-based CE were measured by EIS and Tafel. Therefore the CP-based DSSC with N719 sensitizer were constructed, and achieved the PCE of 1.45% and 1.40% respectively. The above results distinctly present the photovoltaic applications of CQD and CP concurrently derived from green vegetables as sensitizer and counter electrode for DSSC, which indicate the prospect for the realization of high-performance photovoltaic cells from low cost and environmentally friendly natural products

Fluorescence-filled photonic crystal multi-layer films are widely used in laser, sensing, display and other fields due to their photonic bandgap and fluorescence emission properties. In this paper, photonic crystals filled with carbon quantum dots from different precursors have been prepared. It is found that photonic crystals filled with fluorescent carbon quantum dots have optically variable properties excited by ultraviolet light. The optically variable properties of photonic crystals filled with carbon quantum dots at emission peaks of 616, 510 and 450 nm were studied. The fluorescent properties of carbon quantum dots at emission peaks of 616 nm were the best compared to 510 nm and 450 nm. The effects of hole radius R, hole gap d and hole depth h on optically variable properties of fluorescent filled photonic crystals were investigated using 510 nm carbon quantum dots. The results showed that the optically variable properties of fluorescent photonic crystals is strongest when R=400 nm, d=1.5 μm and h=200 nm.

Mechanical resonators based on two-dimensional materials have gained attention for their interesting optical and mechanical properties, which translate into versatile applications such as ultrasensitive force detection and pressure sensing. Optical reflectometry is a technique of choice to measure the flexural vibrations of these resonators. The latter consists in sending normally incident monochromatic light on the resonator and measuring the intensity of reflected light, which varies as the distance d between the resonator and a nearby mirror varies. In this work we consider resonators based on suspended membranes of graphene, molybdenum disulfide and tungsten diselenide, and theoretically investigate the dependence of the reflectance R(d) of the resonator on the angle of incidence θ of the probing light. The optical response of these membranes is accounted for by their complex refractive indices. For s-polarized light, we find that R oscillates as a function of d with an amplitude that increases as theta increases. These results may help enhance the optical readout accuracy of these two-dimensional resonators.

The theoretical limit photoelectric conversion efficiency of the new perovskite/silicon-based tandem solar cell can reach 42%, which has attracted wide attention due to its wide spectral response and low preparation cost. At present, the optical loss of the mechanical stack is large, so the optical design of the laminated battery is crucial. In this paper, perovskite/silicon-based laminated cells with backplate grating structure are used as models to analyze the optical absorption characteristics of stacked battery by FDTD. The results show that the parameters such as the period and height of the backplane grating structure are effective in improving absorption of long wavelength photons in bottom cells, which provides a theoretical basis for the further design of a new perovskite/silicon-based laminate battery.

Nickel (Ni) films with different structure were prepared on fluorine doped tin oxide (FTO) conducting glass by vacuum magnetron sputtering. In this work the effect of sputtering pressure on morphology and electrochemical performances of the as-prepared Ni films was investigated. The morphology and crystal structure of the prepared Ni films were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The results show the thickness of Ni films decreased with the increase of sputtering pressure owing to the decrease of the deposition rate from 0.6 Pa to 1.8 Pa with an inflection point at 1.2 Pa. The Ni films deposited at sputtering pressure of 1.2 Pa possess the highest specific surface roughness, porosity and abundant island structure, contributing to better electrochemical performance of Ni film.

A transparent conductive metal mesh film (TCMMF) was successfully fabricated by a low-cost and simple process. Firstly, the crack mask pattern is obtained after a certain heat treatment process, based on a glass substrate coated with egg-white. Then, a TCMMF was fabricated in combination with a series of processes such as metal deposition and mask removal. In this paper, the film formation mechanism and performance of the TCMMF based on random crack templates are studied, and the TCMMF have also been used in perovskite solar cells (PSCs).The results showed that the TCMMF’s transmittance is more than 90% in the UV-visible range and infrared-visible range. The TCMMF’s surface resistance measured by the four probe method is 20 Ω/□. The performance of the PSCs based on the TCMMF can be comparable to that of the PSCs based on ITO, with a photoelectric conversion efficiency of 13.8%. This provides a possibility for the application of TCMMF in photovoltaic and photovoltaic fields.

Prepared by electron beam evaporation with argon plasma assistance, ultrathin Ge films on JGS1, CaF2 and Si substrates at different deposition temperatures has been investigated by grazing incidence X-ray reflectivity (GIXRR), spectrophotometer, atomic force microscopy. By investigation of the influence of deposition temperature ranging from 100 to 300degC and annealing treatment on transmittance, morphologies of Ge thin films. It can be seen that both deposition temperature exchange and annealing treatment can significantly affect the thickness of Ge thin films. And there is an enhancement of attenuation on films transmittance with the increasing of deposition temperature on JGS1 and CaF2 substrates, while it’s not significant on Si substrate. In addition, it can be seen that the roughness of Ge films on JGS1 and CaF2 substrates has similar variation, which is different from the roughness of Ge films on Si substrate.

To research the initiation of breakdown and the earliest stages of plasma formation, analyzing the ignition time and mechanism is necessary. The ignition time of laser-induced air plasmas is numerically simulated on the basis of air breakdown conditions in atmospheric air. This time is on the order of a few nanoseconds, and increases with increasing laser facula radius and pulse width, and decreases with increasing laser wavelength and incident laser energy. In addition, images obtained using a high-speed camera (NX5-X2) indicate that the ignition process of laser-induced air plasmas includes preionization, ionization, significant ionization, plasma shielding , plasma ignition and extinction.

Six groups of single-layer Alumina (Al₂O₃) thin films with different oxygen flow rate were prepared by ion beam sputtering. The oxygen flow rate changed from 0 sccm to 50 sccm with the interval of 10 sccm. The transmission spectrum, reflection spectrum and ellipsometric reflection spectrum of Al₂O₃ thin films were analyzed by cody-lorentz model inversion calculation. The surface roughness of six groups of samples was measured by white light interferometer. The effects of oxygen flow on band gap, Urbach band-tail absorption, deposition rate, surface roughness, deposition rate of Al₂O₃ thin films were studied. The experimental results showed that oxygen flow directly affects the band gap, Urbach tail absorption, deposition rate, surface roughness and deposition rate of Al₂O₃ thin films.

In order to improve the shielding effectiveness of graphene films, graphene films were prepared by chemical vapor deposition. The effects of hydrogen flow rate, methane flow rate, reaction temperature and reaction time on the electromagnetic shielding properties of the films were investigated. The shielding effectiveness of the film was tested and the preparation process of the film was optimized based on the test results. The results show that when the hydrogen flow rate is 8sccm, the methane flow rate is 15sccm, the reaction temperature is 1030°C, and the reaction time is 30minutes, the shielding effectiveness of the film is 1.2dB (0.3-3000MHz) and the average transmittance is 96%. (400-800nm), the photoelectric comprehensive performance is better.

Yttrium oxide (Y₂O₃) thin films has been prepared on glass substrates at room temperature by thermal evaporation technique using Y₂O₃ powders (99% purity) and then are annealed at different temperatures ranging from 150℃ to 450℃ for 24 hours in air. The effects of the annealing temperatures on the structural and optical properties of the Y₂O₃ thin films were studied. The results show that the refractive index, extinction coefficient and forbidden band width of the Y₂O₃ thin film change to different degrees with the increase of annealing temperature. In addition, the roughness and stress of the Y₂O₃ thin film showed a trend of increasing first and then decreasing. The crystal state of the film is improved, indicating that the grain size becomes large. The research indicates that annealing treatment can effectively change the optical properties and structural properties of the Y₂O₃ thin films which has guiding significance for the selection of optimal heat treatment temperature for Y₂O₃ film modification.

In this work, the electrical conductivity of Ga-doped ZnO (GZO) films was discussed with varying sputtering powers for transparent electrodes. The dependence of the optical bandgap, E_opt, of the GZO films on sputtering power density was expressed by the Burstein-Moss shift model correlated with the carrier concentration in the GZO films. The lowest electrical resistivity of the GZO films was obtained to be 3×10^-4 ohm-cm with carrier concentration of 9.2×10²⁰ cm^-3 and Hall mobility of 22 cm² /Vs. Amorphous InGaZnO (a-IGZO) was developed by radio frequency magnetron sputtering as the active channel layer under different gas flow rates at room temperature. It is revealed that oxygen flow rate played an important role in controlling the conductance in the a-IGZO channel layer. The characteristics of the bottom-gate aIGZO thin film transistors exhibited the saturation field effect mobility of 15.5 cm² /Vs with an on/off current ratio of 10⁵ . The improvement of transistors performance from depletion to enhancement mode is attributed to depressing the carrier concentration to realize normally-off device characteristics.

Plasma-enhanced atomic layer deposition (PEALD) has been widely used in microelectronics due to its precise coating thickness control and high uniformity. Coating qualities are strongly affected by deposition parameters and can be tailored accordingly. In this work, SiO₂ and HfO₂ monolayers were deposited by PEALD on fused silica and BK7 substrates for different measurement. The influence of deposition temperature and precursor pulse time on both coatings were studied. Coating thickness was obtained by ellipsometer and coating roughness was extracted by atomic force microscope. Laser-induced damage threshold (LIDT) and damage morphology were also studied. By optimizing the process parameters, coatings with desired properties can be deposited.