Ta2O5 films are deposited on fused silica substrates by conventional e-beam evaporation. Surface topography and chemical composition are examined by atomic force microscopy （AFM） and x-ray photoelectron spectroscopy...Ta2O5 films are deposited on fused silica substrates by conventional e-beam evaporation. Surface topography and chemical composition are examined by atomic force microscopy （AFM） and x-ray photoelectron spectroscopy （XPS）. The calculation of electron structures of Ta2O5 and Ta2O5-x is attempted using a first-principle pseudopotential method within the local density approximation. The laser-induced damage threshold （LIDT） is performed at 1064, 532 and 355 nm in 1-on-1 regime, respectively. The results show that the LIDT increases with the wavelength increasing, which is in agreement with the wavelength effect. However, the LIDT results are not consistent with the empirical equation （I（λ）=aλm）, which may be attributed to the intrinsic absorption of Ta2O5 at the wavelengths of 532 or/and 355 nm. Moreover, different damage morphologies are observed when the films are irradiated at different wavelengths. It is concluded that the laser damage at 1064 nm is the defect dominant mechanism and at 355 nm it is the intrinsic absorption dominant mechanism, whereas at 532 nm it is the combined defect and intrinsic absorption dominant mechanism.展开更多
This paper reports that carbon microcoils are grown through a chemical vapour deposit process, they are then embedded in silicone rubber, and manipulated to parallel with each other along their axes in the resulting c...This paper reports that carbon microcoils are grown through a chemical vapour deposit process, they are then embedded in silicone rubber, and manipulated to parallel with each other along their axes in the resulting composite. The impedance ｜Z｜ as well as phase angle 8 of both the original carbon microcoil sheets and the aligned carbon microcoil/silicone rubber composites are measured. The results illustrate that carbon microcoils in different forms show different alternating current electric properties. The aligned carbon microcoils in the composites show stable parameters for f 〈 104 Hz but a sharp decrease in both ｜Z｜ and θ for frequencies 〉 10^4 Hz, which will also change as the carbon microcoils are extended. But, the original sheets have a pure resistance with their parameters stable throughout the entire alternating current frequency range investigated.展开更多
文摘Ta2O5 films are deposited on fused silica substrates by conventional e-beam evaporation. Surface topography and chemical composition are examined by atomic force microscopy （AFM） and x-ray photoelectron spectroscopy （XPS）. The calculation of electron structures of Ta2O5 and Ta2O5-x is attempted using a first-principle pseudopotential method within the local density approximation. The laser-induced damage threshold （LIDT） is performed at 1064, 532 and 355 nm in 1-on-1 regime, respectively. The results show that the LIDT increases with the wavelength increasing, which is in agreement with the wavelength effect. However, the LIDT results are not consistent with the empirical equation （I（λ）=aλm）, which may be attributed to the intrinsic absorption of Ta2O5 at the wavelengths of 532 or/and 355 nm. Moreover, different damage morphologies are observed when the films are irradiated at different wavelengths. It is concluded that the laser damage at 1064 nm is the defect dominant mechanism and at 355 nm it is the intrinsic absorption dominant mechanism, whereas at 532 nm it is the combined defect and intrinsic absorption dominant mechanism.
基金Project supported by the Natural Science Foundation of Jiangsu Province of China (Grant No. BK2008129)
文摘This paper reports that carbon microcoils are grown through a chemical vapour deposit process, they are then embedded in silicone rubber, and manipulated to parallel with each other along their axes in the resulting composite. The impedance ｜Z｜ as well as phase angle 8 of both the original carbon microcoil sheets and the aligned carbon microcoil/silicone rubber composites are measured. The results illustrate that carbon microcoils in different forms show different alternating current electric properties. The aligned carbon microcoils in the composites show stable parameters for f 〈 104 Hz but a sharp decrease in both ｜Z｜ and θ for frequencies 〉 10^4 Hz, which will also change as the carbon microcoils are extended. But, the original sheets have a pure resistance with their parameters stable throughout the entire alternating current frequency range investigated.
