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optical constants of aluminum films prepared by electron beam evaporation

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Chinese Optics Letters 2013年第13期11卷 87-89页

作者：姜承慧刘华松刘丹丹 Tianjin Key Laboratory of optical Thin Films Tianjin Jinhang Institute of Technical Physics Tianjin 300192 China

The metal aluminum （Al） is widely used because it has high reflectivity from the ultraviolet to the infrared band. But the new deposited Al films is exposed to the atmosphere, it forms transparent Al2O3 films on its surface at once. In this letter, the Al films is deposited on the quartz substrate by electron beam evaporation. The effect of Al films oxidation on refractive index and extinction coefficient is investigated by spectroscopic ellipsometry （SE）. The optical constants of Al films change with the increase of oxidation time. The two parameters become stable when these films are exposed in air more than 2 days.

关键词： optical constants

Variable angle spectroscopic ellipsometry and its applications in determining optical constants of chalcogenide glasses in infrared

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Chinese Physics B 2018年第6期27卷 454-460页

作者：韦宁宁杨振潘宏波张凡刘永兴王荣平沈祥戴世勋聂秋华 Laboratory of Infrared Material and Devices Advanced Technology Research InstituteNingbo UniversityNingbo 315211China Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province Ningbo 315211China

The principle of variable angle spectroscopic ellipsometry（VASE） and the data analysis models, as well as the applications of VASE in the characterization of chalcogenide bulk glasses and thin films are reviewed. By going through the literature and summarizing the application scopes of various analysis models, it is found that a combination of various models, rather than any single data analysis model, is ideal to characterize the optical constants of the chalcogenide bulk glasses and thin films over a wider wavelength range. While the reliable optical data in the mid-and far-infrared region are limited, the VASE is flexible and reliable to solve the issues, making it promising to characterize the optical properties of chalcogenide glasses.

关键词： chalcogenide glasses/thin films VASE optical constants infrared

Influence of sputtering pressure on optical constants of a-GaAs_(1-x)N_x thin films

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Journal of Semiconductors 2012年第8期33卷 28-31页

作者：贾宝山王云华周路白端元乔忠良高欣薄报学 State Key Laboratory on High Power Semiconductor Lasers Changchun University of Science and Technology

Amorphous GaAsl-xNx （a-GaAsl-xNx） thin films have been deposited at room temperature by a reactive magnetron sputtering technique on glass substrates with different sputtering pressures. The thickness, nitrogen content, carrier concentration and transmittance of the aseposited films were determined experimentally. The influence of sputtering pressure on the optical band gap, refractive index and dispersion parameters （Eo, Ed） has been investigated. An analysis of the absorption coefficient revealed a direct optical transition characterizing the asdeposited films. The refractive index dispersions of the as-deposited a-GaAsl-xNx films fitted well to the Cauchy dispersion relation and the Wemple model.

关键词： a-GaAsx-xNx thin films sputtering deposition optical constants

Determination of optical constants in DUV/VUV

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Chinese Optics Letters 2013年第13期11卷 158-161页

作者：郭春孔明东林大伟柳存定高卫东李斌成 Institute of Optics and Electronics Chinese Academy of Sciences Chengdu 610209 China University of ChineseAcademy of Sciences Beijing 100039 China

An approach for determining the optical constants of the weakly absorbing substrate is developed and applied to obtain the parameters of CaF2 and fused silica substrates in deep ultraviolet （DUV） and vacuum ultraviolet （VUV） range. A method for extracting the optical constants of thin films deposited on strongly absorbing substrate, which is based on the reflectance spectra measured at different angles of incidence, is also presented. The optical constants are determined by fitting the measured spectra to the theoretical models. The proposed method is applied to determine the refractive index and extinction coefficient （n, k） of MgF2 film deposited on silicon substrate by electron beam evaporation with substrate temperature 300 ℃ and deposition rate 0.2 nm/s. The determined n, k values at 193 nm are 1.433 and 9.1×10-4, respectively.

关键词： optical constants

Inversion Methods of optical constants of Semitransparent Solid Materials from Transmittance Spectrograms

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Journal of Harbin Institute of Technology(New Series) 2013年第2期20卷 55-60页

作者： Dong Li Xin-Lin Xia Qing Ai School of Energy Science and Engineering Harbin Institute of Technology Heilongjiang Key Laboratory of Disaster Prevention Mitigation and Protection EngineeringNortheast Petroleum University

The direct calculation models of spectral transmittance of single and double slabs consisted of semitransparent solid materials were developed based on ray trace method,and a new inversion method of optical constants ( k is extinction coefficient and n is refractive index) of materials was proposed based on transmittance spectrograms of double slabs. Differences between the new method and two others currently used methods were studied,and application range of methods was also investigated. optical constants of selenide glass attained in references were selected as true values,and spectral transmittances of glass simulated based on direct calculation model were regarded as experimental values. optical constants of selenide glass were achieved by inverse models. Influences of measurement error on inverse results were also determined. The results showed that: (1) based on transmittance spectrograms of double slabs in which thickness of single slab is the same,the new proposed method can attain optical constants of materials; (2) the effect of optical constants n and k on three inversion methods are urgent larger,but inversed calculation precision of optical constants are higher in most application ranges; (3) the influence of measurement errors existed in experimental datum on the inverse precision of three methods are urgent

关键词： semitransparent solid material optical constants extinction coefficient refractive index inverse model

Study on optical constants inversion and infrared transmission characteristics of aerosol particles

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Journal of Harbin Institute of Technology(New Series) 2011年第6期18卷 1-6页

作者：王希影齐宏牛臣基阮立明 School of Energy Science and Engineering Harbin Institute of Technology Postdoctoral Research Center of Instruments Science and Technology Harbin Institute of Technology

Based on the experimental infrared spectral transmittances,an inverse model has been developed to determine the optical constants of the aerosol particles (SiO2 and Al2O3).Combined with the Mie theory and Kramers-Kronig (K-K) relations,the complex refractive indices of the SiO2 and Al2O3 particles are retrieved.The effects of the measurement errors on the inverse results are also investigated.With the optical constants inversed from the experiment,the discrete ordinate method (DOM) is used to calculate the infrared transmission characteristics of the aerosol particle cloud.Considering the multi-scattering and self-emission of the particles,the equivalent transmittance ratio (ETR) is suggested to evaluate the infrared transmission characteristics of the aerosol particles.Particular attention is given to analyze the effects of the volume fraction and diameters on infrared transmission characteristics.When the volume fraction is larger than 0.001,the particle diameter has little effect on the infrared transmission characteristics.For the uniform monodisperse particles in the detection waveband range of 3-5 μm and 8-12 μm,there exists a critical diameter where the ETR reaches the minimum value.In addition,the ETR of 3-5 μm is smaller than that of 8-12 μm with the same volume fraction and particle diameter.

关键词： aerosol particles optical constants inversion infrared transmission characteristics

Thickness dependence of the optical constants of oxidized copper thin films based on ellipsometry and transmittance

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Chinese Physics B 2014年第8期23卷 112-116页

作者：宫俊波董伟乐代如成王中平张增明丁泽军 Department of Physics University of Science and Technology of China The Center of Physical Experiments University of Science and Technology of China

Thin oxidized copper films in various thickness values are deposited onto quartz glass substrates by electron beam evaporation. The ellipsometry parameters and transmittance in a wavelength range of 300 nm-1000 nm are collected by a spectroscopic ellipsometer and a spectrophotometer respectively. The effective thickness and optical constants, i.e., refractive index n and extinction coefficient k, are accurately determined by using newly developed ellipsometry combined with transmittance iteration method. It is found that the effective thickness determined by this method is close to the physical thickness and has obvious difference from the mass thickness for very thin film due to variable density of film. Furthermore, the thickness dependence of optical constants of thin oxidized Cu films is analyzed.

关键词： thin film optical constants thickness copper

Extraction of optical constants and thickness of nanometre scale TiO2 film

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Chinese Physics B 2005年第11期14卷 2335-2337页

作者：杨莺歌刘丕均王英张亚非 National Key Laboratory of Nano/Micro Fabrication Technology Bio-X DNA Computer Consortium Key Laboratory for Thin Film and Microfabrication of Ministry of Education Institute of Micro and Nano Science and Technology Shanghai Jiaotong University Shanghai 200030 China

TiO2 thin films were deposited on glass substrates by sputtering in a conventional rf magnetron sputtering system. X-ray diffraction pattern and transmission spectrum were measured. The curves of refraction index and extinction coefficient distributions as well as the thickness of films calculated from transmission spectrum were obtained. The optimization problem was also solved using a method based on a constrained nonlinear programming algorithm.

关键词： TiO2 thin films pointwise constrained optimization approach constrained nonlinear programming optical constants parameters extraction

Proton radiation effects on optical constants of Al film reflector

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Chinese Physics B 2006年第5期15卷 1086-1089页

作者：刘海魏强何世禹赵丹 Space Materials and Environment Engineering Laboratory Harbin Institute of Technology Harbin 150001 China

The Al film reflectors can yield a high-reflectance over a broad wavelength region, and have been widely used in the spacecraft optical instruments for high quality optical applications. Under the irradiation of charged particles in the Earth radiation belt, the reflectors could be deteriorated. In order to reveal the deterioration mechanism, the change in optical constants of Al film reflector induced by proton radiation with 60 keV was studied in an environment of vacuum with heat sink. Experimental results showed that when the radiation damage primarily occurs in the Al reflecting film, the extinction coefficient k will gradually decrease with increasing radiation fluence, which results in the decrease of the energies of reflective light. Therefore, the proton radiation induced an obvious degradation of spectral reflectance in the wavelength region from 200 to 800nm on the Al film reflector.

关键词： Al film reflector optical constants radiation damage