Ultrafast third-order optical nonlinearities of the as-deposited and annealed Au:Bi2O3 nanocomposite films deposited by magnetron cosputtering are investigated by using femtosecond time-resolved optical Kerr effect (OKE) and pump–probe techniques. The third-order optical nonlinear susceptibility is estimated to be 2.6×10−10 esu and 1.8×10−9 esu at wavelength of 800 nm, for the as-deposited and the annealed film, respectively. The OKE signal of the as-deposited film is nearly temporally symmetrical with a peak centred at zero delay time, which indicates the dominant contribution from intraband transition of conduction electrons. For the annealed film, the existence of a decay process in OKE signal implies the important contribution of hot electrons. These characteristics are in agreement with the hot electron dynamics observed in pump–probe measurement.
A novel passivation film on GaAs surface has been grown by microwave sulfur glow discharge technique.Auger electron spectroscopy and Rutherford back scattering measurements show that the film is mainly composed of sulfur and gallium,and atomic ratio of gallium to sulfur is about 1∶1.From X-ray diffraction spectroscopy measurememt,GaS is identified to be hexagonal polycrystalline material.The refraction index and dielectric constant of GaS have also been determined.
The polar Kerr rotation, Kerr ellipticity and optical constant n and k change regularly with the increase of Mn doping in Pt layer of Pt/Co multilayers. Through calculation and analyses, in heavy Mn doping the change of the Kerr rotation is due to the off-diagonal elements of dielectric tensor. However, in light Mn dop ing the change of Kerr rotation results from the change in the magneto-optical a nd optical constants. The enhanced magneto-optical Kerr rotation is due to the e nhancement of Pt spin-orbit coupling. The variation of Pt spin-polarization resu lts in the change of diagonal and off-diagonal elements of dielectric tensor.
Thermal stability of resistive switching of stoichiometric zirconium oxide thin films is investigated for high yielding nonvolatile memory application. The Al/ZrO2/Al cell fabricated in the conventional device process shows highly reliable switching behaviour between two distinct stable resistance states. The retention capabilities are also tested under various conditions and temperatures. The excellent performance of Al/ZrO2/Al cell can be explained by assuming that anode/ ZrO2 interface exists and by conducting filament forming/rupture mechanism. The device failure is illustrated in terms of permanent conducting filaments formation.
The multiple beam interference of the laser reflectance is a conventional method used to monitor the growth of thin films. In this paper we present the application of this method for the fabrication of diamond X-ray windows. The growth process and optical properties were studied in real time by in-situ reflectivity measurement and curve fitting. The research results are in good agreement with the measurement results of the SEM, XRD and α-step surface outline. Using the research results, we fabricate a type of Φ4-8 mm backing-free X-ray windows with high transmission successfully. The transmission was measured at Beijing Synchrotron Radiation Facility (BSRF)of the Chinese Academy of Sciences. The samples remained undamaged after the transmission measurement, therefore, the windows showed the distinct advantages of low absorption and strong radiation resistance.
We report the use of a large depth of focus Bessel beam in the fabrication of cell structures. Two axicon lenses are investigated in the formation of high aspect ratio line structures. A sol-gel resin, with good mechanical strength, is polymerised in a modified two-photon polymerisation system. Examples of different two-dimensional grids are presented to show that the lateral resolution can be maintained even in the rapid fabrication of high-sided structures.
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