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Vacuum-air-shift causes trouble to conventional electron beam evaporation (EBE) coatings. This study compares the protection effect of ion assistance and the ALD (atomic layer deposition) Al2O3 capping layer. The vacuum-air-shift was reproduced on an EBE Ta2O5 single-layer film, a Ta2O5/SiO2 double-layer coating, and a high-reflectance mirror. Similar samples were prepared by EBE assisted with ion beam bombardment. Part of the as-deposited coatings were capped by ALD Al2O3 film with a thickness of about 100 nm. The vacuum-air-shift of the samples was tested with an in-situ spectrophotometer. The cross-section of the coatings was imaged by a scanning electron microscope. The ion assistance was found to reduce the vacuum-air-shift to a limit extent, while the ALD capping film was found to eliminate the vacuum-air-shift. The mechanism of the two protection techniques was analyzed, and their usage was compared and discussed. The ALD capping technique may be used in high precision EBE coatings with convenience and low cost.

This paper investigated the laser-induced damage mechanism of amorphous and crystalline scandium oxide (Sc2O3) films prepared by ion beam sputtering (IBS) and annealed at different temperatures. A significant increased laser-induced damage threshold (LIDT) at 355 nm wavelength was obtained by amorphous film annealed slightly below the crystallization temperature, which was above 300% higher than those of crystalline films. Meanwhile, the damage morphologies of amorphous and crystalline films were totally different. Measurement of the absorption of films showed that higher absorption led to a large distinction between the LIDTs of films. Energy dispersive spectroscopy (EDS) patterns revealed very uniform distributions of elements without obvious aggregation phenomenon. Positron annihilation spectroscopy (PAS) indicated that vacancy defect increased the absorption and heavily reduced the resistance of films for 355 nm wavelength laser. The investigation in this study would promote the understanding of the laser-induced damage mechanism of amorphous and crystalline films and provide an effective method to increase LIDTs at 355 nm wavelength.

the method of treating multi-photon ionization as some one-photon-absorption processes by introducing transition states has achieved good applications. In this paper, this method has been improved to extend its application scope of laser pulse width. In the improved model, some parameters without explicit physical meaning have been removed. For example, the parameter of energy fraction used for evaluating lattice temperature has been discarded, and the lattice temperature was evaluated according to an electron-phonon scattering process. Besides, more ionization mechanisms have been considered in calculating the electron density. The model described in this paper is suit for analyzing the damage processes induced by laser pulses with pulse width from femtosecond to nanosecond.

Scandium oxide (Sc2O3) thin films with different numbers of oxygen defects were prepared by ion-beam sputtering under different oxygen flow rates. The results showed that the oxygen defects heavily affected crystal phases, optical properties, laser-induced damage threshold (LIDT) and surface quality of Sc2O3 films. The thin film under 0 standard-state cubic centimeter per minute (sccm) oxygen flow rate had the largest number of oxygen defects, which resulted in the lowest transmittance, LIDT and the worst surface quality. In addition, the refractive index of 0 sccm Sc2O3 film could not be measured in the same way. When the oxygen flow rate was 15 sccm, the Sc2O3 film possessed the best transmittance, refractive index, LIDT and surface roughness due to the lowest number of oxygen defects. This work elucidated the relationship between oxygen defects and properties of Sc2O3 films. Controlling oxygen flow rate was an important step of limiting the number of oxygen defects, which is of great significance for industrial production.

Atomic layer deposition has promising application in optical coatings because of the self-terminating feature. An ideally self-terminating ALD process is based on the saturate chemi-sorption and complete purging of the desorbed precursor molecules. The kinetics of adsorption and desorption are analyzed, providing instruction for the development of ALD process. The exposure length is related to the partial pressure and molecule mass, while the purging length is dependent on the physi-sorption potential energy and substrate temperature. The GPC versus pulse length of ALD Al2O3 and HfO2 are measured. With a set of properly selected parameters, film layers with distinctive self-terminating feature are obtained. A coating consisting of several nanolaminates is analyzed with TEM to study the ALD film structure. An anti-reflection coating is deposited, controlling the film thickness by counting the cycles. The laser resistance of the ALD Al2O3 film, HfO2 film and anti-reflection coating is studied. The results certify the analysis and indicate a promising application in developing a self-terminating ALD process for a new material on a new plant.

Gold nanorods were prepared by seed-mediated growth method and were kept inaqueous solution between 45 and 105 °C. It was found that the longitudinal absorption peak of the gold nanorods obviously moved to a shorter wavelength between 60 and 90 °Cand this blue shift phenomenon disappeared after aperiod of time. In this paper, based on the theories of the liquid-like shell, combining the rule that the metal Gibbs free energy changes with temperature, the heat induced deformed mechanism has been studied and especially why the gold nanorods can be stably kept in aqueous solution at high temperature has been analyzed.

Aiming at the problem that the damage threshold of gold coated grating is relatively low, a dielectric film is considered on the gold coated gratings as a protective layer. The thickness range of the protective layer is determined under the prerequisite that the diffraction efficiency of the gold coated grating is reduced to an acceptable degree. In this paper, the electromagnetic field, the temperature field and the stress field distribution in the grating are calculated when the silica and hafnium oxide are used as protective layers, under the preconditions of the electromagnetic field distribution of the gratings known. The results show that the addition of the protective layer changes the distribution of the electromagnetic field, temperature field and stress field in the grating, and the protective layer with an appropriate thickness can improve the laser damage resistance of the grating.

Material with tailorable optical constants was favorable in coating design. The Ion Beam Sputtering technology was used to produce mixture films with tailored refractive indices by utilizing a movable target composed of two materials. A model was established to study the calibration curve representing different refractive indices at different target positions. Boltzmann expression was found to well fit the calibration curve with several parameters. Rugate filters composed of over 100 different mixture layers with tailored refractive indices were fabricated and studied.

The dielectric constant and electrical conductivity of a composite of two insulators, poly(1,1-difluoroethylene) (yellow) and K(2)CO(3) (white), increased dramatically near the percolation threshold f(c) (f=concentration of K(2)CO(3)). This intriguing phenomenon can be interpreted in terms of interface percolation caused by the formation of chemically activated interfaces.

0.95Pb(Sc0.5Ta0.5)O3–0.05%PbTiO3 (PSTT5) thin films with and without a Pb(Zr0.52,Ti0.48)O3 (PZT52/48) seed layer were deposited on Pt/Ti/SiO2/Si(1 0 0) substrates by RF magnetron sputtering. X-ray diffraction patterns indicate that the PSTT5 film with a PZT52/48 seed layer exhibited nearly pure perovskite crystalline phase with highly (4 0 0)-preferred orientation. Piezoresponse force microscopy observations reveal that a large out-of-plane spontaneous polarization exists in the highly (4 0 0)-oriented PSTT5 thin film. The PSTT5/PZT(52/48) possesses good ferroelectric properties with large remnant polarization Pr (12 μC/cm2) and low coercive field Ec (110 kV/cm). Moreover, The perfect butterfly-shaped capacitance–voltage characteristic curve and the relative dielectric constant as high as 733 is obtained in this PSTT5 thin film at 100 kHz.

Water-soluble ZnS:Co 2+ nanocrystals (NCs) were synthesized by a low temperature hydrothermal process using 3-mercaptopropionic acid (MPA) as capping agent and the influence of doping on the optical properties of ZnS:Co 2+ NCs was investigated. It was found that the ZnS:Co 2+ NCs are highly crystalline and show zinc blende structure with an average particle size of about 7 nm. The lattice constant of the ZnS:Co 2+ NCs decreases slightly by the introduction of Co 2+ . The Co dopants were well doped into the ZnS:Co 2+ NCs, as confirmed by X-ray photoelectron spectroscopy(XPS) and the 4 A 2 (F) → 4 T 1 (P) transition of Co 2+ was detected from the UV–vis absorption spectra. The absorption edge of the ZnS:Co 2+ NCs is blue-shifted as compared with that of bulk ZnS, indicating the quantum confinement effect. The PL intensity of the NCs shows the maximum value when the Fe-doping concentration is 0.5 at.%.

Ion Beam Sputtering technique was investigated to provide mixture layers with tunable refractive indices. Complex coating design was able to realize by setting the refractive index as variable. A rugate filter was deposited successfully.

Rugate and high/low quarter-wave stacks high reflector coatings for 1064 nm have been prepared with Ta 2 O 5 and SiO 2 by an ion-beam sputtering technique. A laser-induced damage experiment of the samples has been conducted at 1064 nm with pulse duration of 5 ns [full width at half maximum (FWHM)]. These two samples’ damages both initiate at defects and show almost the same damage threshold within the experimental error. Nevertheless, the damage morphology on rugate is less severe at higher fluences. The thermal shock wave induced by a nanosecond pulsed laser is considered to be the main cause of catastrophic damage.

We show in this paper single-shot and multi-shot laser-induced damage thresholds (LIDTs) of HfO2/SiO2 high reflective films (the reflectance = 99.9%) are affected by the presence of a water layer absorbed on the surface of the porous films. When the water layer was removed with the process of pumping, the single-shot LIDT measured in vacuum dropped to ∼48% of that measured in air, while the multi-shot LIDT in vacuum dropped to ∼47% of its atmospheric value for the high reflective films. Typical damage micrographs of the films in air and in vacuum were obtained, showing distinct damage morphologies. Such atmosphere dependence of the laser damage morphology was found to originate from that formation of a water layer on the surface of porous films could cause an increase of horizontal thermal conductivity and a reduction of vertical thermal conductivity. Moreover, laser-induced periodic ripple damages in air were found in the SiO2 layer from the micrographs. A model of deformation kinematics was used to illustrate the occurrence of the periodic ripple damage, showing that it could be attributed to a contraction of the HfO2 layer under irradiation by the 5-ns laser pulses in air.

Pb(Zr0.8Ti0.2)O3 (PZT80/20) thin films were deposited on the Pt(111)/Ti/SiO2/Si(100) substrates by RF magnetron sputtering. Mainly perovskite crystalline phase with highly (202)-preferred orientation, determined by x-ray diffraction, was formed in the lead zirconate titanate (PZT)(80/20) thin films. Polarization measurements of the unannealed and aged films showed a clear double hysteresis loop. However, the double hysteresis loop phenomenon was greatly suppressed in the PZT thin films annealed under pure oxygen, and thus they exhibited larger remnant polarization (Pr = 6.3 μC/cm2). The related mechanism for the appearance of constricted and double hysteresis loops was investigated to be associated with the realignment and disassociation of defect dipoles via oxygen octahedral rotations or oxygen vacancy diffusion. The butterfly-shaped C-V characteristic curve with a valley gave further evidence for double hysteresis loop characteristic in the unannealed and aged PZT thin films.