Cheng Xinbin

HfO 2 /SiO 2 chirped mirrors manufactured by electron beam evaporation

A HfO2/SiO2 chirped mirror was manufactured by electron beam evaporation to increase the laser resistance. The hybrid monitoring strategy utilizing both monochromatic monitoring and quartz crystal monitoring was applied to the deposition compared to the single optical monitoring method. The coatings were characterized by transmission spectrophotometer and white light interferometry, and the experimental results showed that the chirped mirror monitored with the hybrid strategy possessed high reflectivity (>99.7%) and tolerable group delay dispersion oscillation (-50±20 fs2) in the spectra range of 740-860 nm.

Fabrication and Characterization of Ni Thin Films Using Direct-Current Magnetron Sputtering

Ni films are deposited by using ultra high vacuum dc magnetron sputtering onto silicon substrates at room temperature, and the high-quality and high-density films are prepared. The parameters, such as thickness, density and surface roughness, are obtained by using small-angle x-ray diffraction (XRD) analyses with the Marquardt gradient-expansion algorithm. The deposition rate is calculated and the Ni single layer can be fabricated precisely. Based on the fitting results, we can find that the surface roughness of the Ni films is about 0.7 nm, the densities of Ni films are around 97% and the deposition rate is 0.26 nm/s. The roughness of the surface is also characterized by using an atomic force microscope (AFM). The changing trend of the surface roughness in the simulation of XRD is in good agreement with the AFM measurement.

High Spectral Resolution Mo/Si Multilayers Working at High Order Reflection

The high reflectance orders are used to improve the spectral resolution of Mo/Si multilayers. The multilayers for the first-, second- and third-order reflectance are designed and optimized, respectively. These multilayers are fabricated by using a directed current magnetron sputtering system, and the reflectivity is measured in an extreme ultraviolet range by synchrotron radiation. The experimental results show that the spectral resolution λ/Δλ (λ = 14 nm) increases from 24.6 for the first order to 66.6 for the third order.

HfO 2 /SiO 2 Chirped Mirrors Manufactured by Electron Beam Evaporation

A HfO2/SiO2chirped mirror was manufactured by E-beam evaporation to increase the laser resistance. The experimental results showed that the mirror possess high reflectivity and tolerable GDD oscillation in the spectra range of 740-860 nm.

Design, fabrication and characterization of the X-ray supermirrors

The design, fabrication and characterization of the X-ray supermirrors are discussed in this paper. Using the local optimization method of simplex algorithm and the global one of simulated annealing algorithm with different initial multilayer structures, we designed the broad angular band supermirrors with different grazing incidence angle intervals at the energy of 8.0 keV (the Kα line of Cu) and the broad energetic band supermirrors with different energy intervals at fixed grazing incidence angles. The fabricating techniques for depositing non-periodic multilayers are also studed. The W/C and W/Si supermirrors are deposited on silicon substrates and characterized by a high resolution X-ray D1 diffractometer from Bede Company, UK. Choosing the interface roughness and the densities of the materials as independent variables, some measured reflectivity curves are fitted using the Debye-Waller factor with interface roughness. The experimental results show that the optical performances of the fabricated supermirrors are in agreement with the designed ones.