Jianda Shao

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (287)351.98 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Laser-induced damage behaviors of the chirped mirrors (CMs) are studied by single 800nm-38fs lasers. The CMs provide group delay dispersion (GDD) of around -60fs2 and average reflectivity of about 99.4% with bandwidth range of 200nm~300nm at a central wavelength of 800nm. Interestingly, a circular blister feature appears in the CMs at a wide range of laser fluence. Optical Microscope, Atomic Force Microscope, Scanning Electron Microscope and Surface Profiler, are applied to describe the blister characteristics. An adiabatic expansion model of ideal gas is adopted to illustrate the formation dynamics of blisters. The evolution of blisters can be explained by partial evaporation of the film and a subsequent gas expansion, driving the bulging of the film stack up to the stress limit, where the blister fractures. According to this model, the energy absorption ratio of blisters increases monotonously with increasing laser fluence before the occurrence of focal spot confinement effect.
    Applied Optics 05/2014; 53(15):3347-3354. · 1.69 Impact Factor
  • Jian Sun, Weili Zhang, Kui Yi, Jianda Shao
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    ABSTRACT: A model is developed to improve thickness uniformity of coatings on spherical substrates rapidly and automatically using fixed shadow masks in a planetary rotation system. The coating thickness is accurately represented by a function composed of basic thickness, self-shadow effect, and shadow mask function. A type of mask with parabolic contours is proposed, and the thickness uniformity of coatings on spherical substrates can be improved in a large range of ratios of clear aperture (CA) to radius of curvature (RoC) by optimizing shadow masks using a numerical optimization algorithm. Theoretically, the thickness uniformity improves to more than 97.5% of CA/RoC from -1.9 to 1.9. Experimentally, the thickness uniformities of coatings on a convex spherical substrate (CA/RoC = 1.53) and on a concave spherical substrate (CA/RoC=-1.65) improve to be better than 98.5% after corrected by the shadow masks.
    Chinese Optics Letters 05/2014; 12(5). · 1.07 Impact Factor
  • Jian Sun, Xu Li, Weili Zhang, Kui Yi, Jianda Shao
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    ABSTRACT: As important components in deep-ultraviolet (DUV) optics, especially 193 nm lithographic systems, high-reflectivity (HR) mirrors with excellent optical properties and long lifetimes are needed urgently. In this study, we designed and produced three HR coatings for 193 nm on fused quartz substrates: Al2O3/AlF3 coating, LaF3/AlF3 coating and a double stack mirror with combined Al2O3/AlF3 and LaF3/AlF3. The reflectance of the Al2O3/AlF3 coating with 14 layer pairs reached 98.0% at 193 nm. However, the absorption of Al2O3 prevented the reflectance to increase further. The maximum reflectance of the LaF3/AlF3 coating with 15 layer pairs reached 98.1%, with initial micro-cracks formation. The reflectance decreased as the number of layer pairs increased to 16 because of numerous micro-cracks. The mirror with combined Al2O3/AlF3 and LaF3/AlF3 coatings which combined their advantages obtained a reflectance of 98.8% at 193 nm after deposition. This value could still reach 98.5% at 4 months after deposition and remain stable thereafter. Therefore, the combined coating of Al2O3/AlF3 and LaF3/AlF3 is an excellent candidate for practical application.
    Optics & Laser Technology 03/2014; · 1.37 Impact Factor
  • Jian Sun, Jianda Shao, Kui Yi, Weili Zhang
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    ABSTRACT: As a low refractive index material widely used in coatings for deep-ultraviolet optical systems, magnesium fluoride (MgF<sub>2</sub>) films were prepared by electron beam evaporation at different substrate temperatures. The effects of the substrate temperatures on the optical properties in vacuum and in air, microstructures, and composition were investigated, as were the microstructures, their composition, and the relation between them. In vacuum, the substrate temperature directly affected the microstructures which dominated the packing density and inhomogeneity along the film thickness. When the films were exposed to air, the refractive index increased and a nonmonotonic change trend of the refractive index with substrate temperature was observed due to adsorbed water and magnesium oxide (MgO) formed in the film. While a moderate amount of MgO reduced absorption loss by decreasing vacancy defects, excessive MgO increased the absorption loss because of the high extinction coefficient of the oxide.
    Applied Optics 03/2014; 53(7):1298-305. · 1.69 Impact Factor
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    ABSTRACT: Metal multi-layer dielectric gratings (MMDG) for pulse compressors in high-energy laser systems should provide broad bandwidth as well as high laser-induced damage thresholds. The non-uniform optical near-field distribution of MMDG is an important factor that limits damage resistant capabilities. MMDG for pulse compressors operating at 800 nm with a corrugated SiO2 layer are designed by using a genetic algorithm and the Fourier mode method. The diffraction efficiency, bandwidth, and near-field distribution of the MMDG are theoretically investigated. For the single dielectric match layer grating, the bandwidth is 140 nm, if the thickness and refractive index of the match layer are changed, the maximum electric field in the grating ridge, match layer, and metal layer of the grating increases with the decrease in grating diffraction efficiency. For the multi-dielectric match layer grating, the bandwidth and the maximum electric field in the metal layer decrease with the increase in high- and low-index material pairs, and the maximum electric field in the grating ridge and match layer initially decreases and then increases. Over a wide wavelength range, the maximum electric field in the grating ridge, match layer, and metal layer is minimal near the central wavelength. Moreover, MMDG should be used at larger incident angles while keeping enough bandwidth to reduce the electric field in the grating.
    Applied Physics B 02/2014; · 1.78 Impact Factor
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    ABSTRACT: We report the periodic concentric surface structures on SiO<sub>2</sub> layer induced by a single shot nanosecond laser pulse at 1.06 μm. The fringe period of the structures ranges from 7.0 μm to 26.8 μm, depending on the laser fluence and the distance from central defect precursor. The size and depth of the damage sites increase almost linearly with the laser fluence from 19.6 J/cm<sup>2</sup> to 61 J/cm<sup>2</sup>. Plasma flash was clearly observed during the damage process. We attribute the formation mechanism of the structures to the interference between the reflected laser radiations at the air/shock-front and the shock-front/film interfaces.
    Optics Express 02/2014; 22(3):2948-54. · 3.55 Impact Factor
  • Yun Cui, Kui Yi, Hu Guohang, Jianda Shao
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    ABSTRACT: Coating stacks of HfO2/SiO2 and Ta2O5/SiO2 were separately prepared by electron beam evaporation and dual ion beam sputtering. Damage characteristics at the interlayer interfaces were analyzed after irradiation of the coatings by a 1064 nm laser. The cross-sectional morphologies of damage spots indicated that peeling-off damages always occurred at the interface where the low refractive index material (SiO2) was deposited on the high refractive index material (HfO2 or Ta2O5). The effects of interface microstructure and components on peeling-off damages were also discussed. The microstructure of the interface was not a major factor that influenced peeling-off damages. Incomplete oxides (SiOx) and Na, K, Li ions accumulated near the interface and caused the formation of micro-defects layers with nano-sized thicknesses. Micro-defects layers maybe reduced adhesion of different interfaces and formed plasmas by absorbing laser energy. Finally stripping damages happened from micro-defects layers during irradiation by a 1064 nm laser.
    Applied Surface Science 01/2014; 290:71–79. · 2.54 Impact Factor
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    ABSTRACT: Wave propagation of symmetry incidence on the biaxial birefringent film is discussed in this paper based on the characteristic matrix method. Furthermore, based on the refractive index surface, the refractive indices and effective optical admittances of the forward and backward propagating extraordinary waves (p-polarized wave) are analyzed in detail. With regard to the symmetry incidence, optical properties, such as the input optical admittance, transmittance and reflectance, are not identical for an extraordinary wave under common condition, i.e., angular selectivity. Based on an analysis of refractive index surface, the effective optical admittances of the forward and backward propagating extraordinary waves are equal in this particular case; transmittance and reflectance under the symmetry incidence are completely overlapped, similar to findings in the isotropic thin film. We validate our analysis using the developed software package. Based on the novel theory analysis, we can gain a new perspective of symmetry incidence about angular selectivity for the biaxial birefringent film.
    Optics Communications 01/2014; 325:1–4. · 1.44 Impact Factor
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    ABSTRACT: Commercial fused silica (50 mm diameter × 5 mm thickness) irradiated by single pulse of Nd:YAG laser (1064 nm, 12 ns) is experimentally investigated. The exit surface of fused silica is easier to be damaged than the entrance surface, so in this paper we only study the damage formed on the exit surface. The typical damage morphologies, irradiated at normal and oblique incidence, were observed with scanning electron microscope and atomic force microscope. The concentric ring structures with a central defect precursor are appeared in all damage sites. Furthermore, the whole damage sites are filled with the surface periodic striped structures, which direction is perpendicular to the incident electric field. Further analysis show that the incident energy has great effect on the size of damage sites, the depth of damage sites, and also the depth of the ripples, but has no effect on the period of the ripples. Additional experiments are performed to investigate the dependency between the period of ripples and the incident angle.
    Applied Surface Science 01/2014; 309:79–84. · 2.54 Impact Factor
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    ABSTRACT: We report on an 800 nm center-wavelength metal/multilayer-dielectric grating (MMDG) with broadband, high diffraction efficiency. The trapezoidal grating ridge consists of an HfO<sub>2</sub> layer sandwiched between two SiO<sub>2</sub> films. Combining the advantages of SiO<sub>2</sub> and HfO<sub>2</sub>, the grating ridge reduces the difficulties of grating ridge attainment. For such a configuration, high-performance MMDG can be successfully fabricated using the existing technology. Experimentally we demonstrated a 163 nm bandwidth MMDG with -1st-order diffraction efficiency greater than 90%. The fabricated MMDG achieved high performance as the design with large fabrication tolerances.
    Optics Letters 01/2014; 39(1):170-3. · 3.39 Impact Factor
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    ABSTRACT: Four mirror coatings were designed for transporting 1064 nm light, and prepared under the same process parameters. The laser induced damage threshold (LIDT), electric field distribution, as well as the damage morphology of the prepared transport mirror coating was investigated. The results indicate that the SiO2 overcoat layer and electric field distribution have a great impact on the LIDT and damage morphology of the transport mirror coating. A thicker SiO2 overcoat layer can suppress the delamination damage morphology, and significantly increase the LIDT. For the designs with similar SiO2 overcoat layer thickness, the nano-absorbing defects can survive at higher laser fluence in the design with lower electric field intensity. In addition, the HfO2 over SiO2 interface has a better interfacial strength and less “invisible” nano-absorbing defects than the SiO2 over HfO2 interface, suggesting that improving the SiO2 over HfO2 interfacial quality will be an effective way to enhance the laser damage performance of the transport mirror coating.
    Optics Communications 01/2014; 319:75–79. · 1.44 Impact Factor
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    ABSTRACT: We present a monitoring strategy based on using two pieces of witness glass, which are brought to the measuring position in a specially chosen sequence, each witness glass is monitored by one single wavelength. To reduce the thickness error, some thick layers are divided into two layers and monitored by different witness glasses. Theoretical analysis and experimental results have demonstrated that the proposed monitoring strategy can achieve spectral performance close to the theoretical design.
    Vacuum. 11/2013; 97:44–48.
  • Optik - International Journal for Light and Electron Optics 11/2013; 124(21):5154-5157. · 0.77 Impact Factor
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    ABSTRACT: A reliable method, combining femtosecond (fs) laser mitigation and chemical (HF) etching, has been developed to mitigate laser-damage growth sites on a fused silica surface. A rectangular mitigation site was fabricated by an fs laser with a raster scan procedure; HF etching was then used to remove the redeposition material. The results show that the mitigation site exhibits good physical qualities with a smooth bottom and edge. The damage test results show that the growth threshold of the mitigation sites increases. Furthermore, the structural characteristic of samples was measured by a photoluminescence (PL) spectrometer, and the light intensification caused by damage and mitigation sites was numerically modeled by the finite-difference time-domain (FDTD). It revealed that the removal of damaged material and structure optimization contribute to the increase of the damage growth threshold of the mitigation site.
    Applied Optics 10/2013; 52(29):7186-93. · 1.69 Impact Factor
  • Yongqiang Hou, Hongji Qi, Kui Yi, Jianda Shao
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    ABSTRACT: A slanted columnar TiO2 sculptured anisotropic thin film is prepared using the glancing angle deposition (GLAD) technique. We extend the inference regarding the optical properties of a uniaxial birefringent film based on theoretical analysis to include the more general case of a multilayer biaxial birefringent thin film, the optic axis of which is in the incident plane. We also investigate in detail the symmetrical angularselective transmittance performances of TiO2 biaxial anisotropic thin films for light incident at the same angle but coming from opposite sides of the surface normal. The tilted nanocolumn microstructures of the birefringent thin films induce optical anisotropy. The transmisson spectra for the p-polarized wave of TiO2 biaxial anisotropic thin film measured in the experiment almost overlap at the symmetrical oblique incidence at the ±θ0 angles, which validates our theoretical derivation.
    Chinese Optics Letters 10/2013; 11(10). · 1.07 Impact Factor
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    ABSTRACT: Nanosecond single and multiple pulse laser damage studies on HfO<sub>2</sub>/SiO<sub>2</sub> high-reflective coatings were performed at 1064 nm. The evolution of LIDT and 100% damage probability threshold under multiple irradiations revealed that fatigue effects were affected by both laser fluence and shot numbers. And the damage probability curves exhibiting different behaviors confirmed experimentally that this fatigue effect of the dielectric coatings was due to material modification rather than statistical effects. By using a model assuming Gaussian distribution of defect threshold, the fitting results of LID probability curves indicated the turning point appeared in the damage probability curves under large shot number irradiations was just the representation of the existence of newly created defects. The thresholds of these newly created defects were exponential decrease with irradiated shot numbers. Besides, a new kind of damage morphologies under multiple shot irradiations were characterized to further expose the fatigue effect caused by cumulative laser-induced material modifications.
    Optics Express 09/2013; 21(19):22476-22487. · 3.55 Impact Factor
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    ABSTRACT: Multiple laser irradiations induce a critical issue as regards the lifetime of optical components. HfO2/SiO2 AR coatings for 1064 nm were prepared by conventional electron beam deposition. The evolution of laser-induced damage threshold (LIDT) and 100% damage probability threshold with shot numbers were investigated to illustrate the incubation mechanism of defect-induced damages and the intrinsic material modifications of coatings. It was found that the multi-shot LIDTs were lower than that of single-shot because of “fatigue effect”. The 100% damage probability threshold also decreased with increasing shot numbers. This incubation phenomenon implied laser-induced modifications to the coating material that weaken it to subsequent pulse exposures. LID probability curves simulated with a statistical model assuming Gaussian distribution of defect threshold were used to highlight information on defects. Simulation results showed that the thresholds of different kinds of defects decreased with the increase of shot numbers.Optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and step profiler were employed in mapping damage morphology features and damage depth to discuss the initiators and mechanism of damage initiation. Additionally, damage regions were accessed by X-ray photoelectron spectroscopy (XPS) to indicate the changes in elemental content and valence of the materials with increasing pulse numbers.
    Optics Communications 08/2013; s 301–302:12–18. · 1.44 Impact Factor
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    ABSTRACT: A reliable method, combining a wet etch process and real-time damage event imaging during a raster scan laser damage test, has been developed to directly determine the most dangerous precursor inducing low-density laser damage at 355 nm in fused silica. It is revealed that ∼16% of laser damage sites were initiated at the place of the scratches, ∼49% initiated at the digs, and ∼35% initiated at invisible defects. The morphologies of dangerous scratches and digs were compared with those of moderate ones. It is found that local sharp variation at the edge, twist, or inside of a subsurface defect is the most dangerous laser damage precursor.
    Optics Letters 08/2013; 38(15):2632-5. · 3.39 Impact Factor
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    ABSTRACT: An in situ multi-beam optical sensor system was used to monitor and analyze the force per unit width (F/w) and stress evolution during several stages in magnetron-sputtered SiO2 and SiNx films. Stress was observed to relieve quickly after interrupt and recover rapidly after growth resumption in both films. Stress relief was reversible in SiO2 film but partial reversible in SiNx film. Stress relief results from both physical and chemical adsorption. Stress recovery is caused by physical desorption. And chemical adsorption results in an irreversible stress relief component. No chemical adsorption occurs in SiO2 film because of the stable chemical structure. The relationship between adsorption kinetics and films' mechanical behavior is revealed.
    Journal of Applied Physics 07/2013; 114(3). · 2.21 Impact Factor
  • Jian Sun, Xu Li, Weili Zhang, Kui Yi, Jianda Shao
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    ABSTRACT: AlF3 thin films were prepared by thermal evaporation at different substrate temperatures and deposition rates. The relationships between optical properties, mechanical properties and laser-induced damage threshold (LIDT) at 355nm of AlF3 films were discussed. Both absorption and stress increased with increasing substrate temperatures and deposition rates, which was a disadvantage to laser-induced damage resistance. Meanwhile, interfacial adhesion and hardness increased with substrate temperatures and deposition rates, which was an advantage to enhance the LIDT. The LIDT increased from room temperature to 200°C duo to increasing interfacial adhesion and hardness, and then decreased to 300°C duo to increasing absorption and stress. The LIDT decreased with deposition rates due to increasing absorption and stress.
    Proc SPIE 07/2013;

Publication Stats

716 Citations
351.98 Total Impact Points

Institutions

  • 2004–2014
    • Chinese Academy of Sciences
      • Anhui Institute of Optics and Fine Mechanics
      Peping, Beijing, China
  • 2003–2013
    • Northeast Institute of Geography and Agroecology
      • • Anhui Institute of Optics and Fine Mechanics
      • • Graduate School
      Beijing, Beijing Shi, China
    • Shanghai Institute of Optics and Fine Mechanics, CAS
      • Key Laboratory of Materials for High Power Laser, CAS
      Shanghai, Shanghai Shi, China
  • 2009
    • San Diego Zoo
      San Diego, California, United States
    • North University of China
      Yangkü, Shanxi Sheng, China
    • Shenzhen University
      • College of Physics Science and Technology (CPST)
      Bao'an, Guangdong, China
  • 2008
    • Xiamen University
      • Department of Physics
      Xiamen, Fujian, China