Laser-induced damage threshold of the antireflection coatings on quartz and sapphire under different laser modes

The laser-induced damage threshold (LIDT) and damage morphology of antireflection (AR) coatings on quartz and sapphire are investigated. A very interesting phenomena is found in the measurement. In the case of a single pulse laser, the LIDT of the AIR coatings on quartz is higher than that of sapphire. On the contrary, for a free-pulse laser, the LIDT of AIR coatings on sapphire is higher than that of quartz. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

三硼酸锂晶体上1064 nm, 532 nm, 355 nm三倍频增透膜的设计

采用矢量法设计了三硼酸锂晶体上1064 nm、532 nm和355 nm三倍频增透膜,结果表明1064 nm、532 nm和355 nm波长的剩余反射率分别为0.0017％、0.0002％和0.0013％。根据误差分析,薄膜制备时沉积速率精度控制在＋5.5％时,1064 nm、532 nm和355 nm波长的剩余反射率分别增加至0.20％、0.84％和1.89％。当材料折射率的变化控制在＋3％时,1064 nm处的剩余反射率增大为0.20％,532 nm和355 nm处分别达0.88％和0.24％。与薄膜

LiB3O5晶体上四倍频增透膜设计

采用矢量法设计了三硼酸锂（LiB3O5，LBO）晶体上1064nm、532nm、355nm和266nm四倍频增透膜．结果表明，在1064nm、532nm、355nm和266nm波长的剩余反射率分别为0．0019％、0．0031％、0．0061％和0．0047％．根据容差分析，薄膜制备时沉积速率准确度控制在＋6．5％时，基频、二倍频、三倍频和四倍频波长的剩余反射率分别增加至0．24％、0．92％、2．38％和4．37％．当薄膜材料折射率的变化控制在＋3％时，1064nm波长的剩余反射率增大为0．18％，532nm、355nm和266nm波长分别达0．61％，0．59％，0．20％．与薄膜物理厚度相比，膜层折射率对剩余反射率的影响大．对膜系敏感层的分析表明，在1064nm和266nm波长，从入射介质向基底过渡的第二层膜厚度变化对剩余反射率的影响最大，其次是第一膜层．在532nm和355nm波长，从入射介质向基底过渡的第一和第四膜层是该膜系的敏感层．误差分析也表明，薄膜材料的色散对特定波长的剩余反射率具有明显影响，即1064nm、532nm、355nm和266nm波长的剩余反射率分别增加至0．30％、0．23％、0．58％和3．13％．

Novel method for design of surface relief guided-mode resonant gratings at normal incidence

We demonstrate that the surface relief guided-mode resonant gratings with specified central wavelength and FWHM in the visible wavelength range can be designed by analyzing the complex poles of Reflectance and transmission coefficient matrix algorithm (RTCM), a variant of S-matrix propagation algorithm proposed for calculation of multilayer gratings. In addition, FWHM is computed with couple-mode (CM) theory of resonant gratings which is firstly extended by Norton et al. in calculation of waveguide grating. Furthermore, the side band reflections of the filter can be reduced to less than 5% in the visible wavelength with the antireflection (AR) design technique widely used in the thin-film field. (C) 2008 Elsevier B.V. All rights reserved.

引入过渡层提高介质减反膜的抗激光损伤阈值

提出了一种用于提高介质减反膜的损伤阈值的新的方法，在H2.5L (H:HfO2, L:SiO2)的膜层与基底之间引入4个1/4光学厚度的SiO2薄膜，发现抗激光损伤阈值提高了50%，并且保持1064nm处的反射率低于0.09%。本文分析了造成这一提高的机制，一定厚度的氧化硅过渡层的引入是一种提高介质减反膜的损伤阈值的灵活有效的方法。

Influence of different substrates on laser induced damage thresholds at 1064 nm of Ta2O5 films

Ta2O5 films are prepared on Si, BK7, fused silica, antireflection (AR) and high reflector (HR) substrates by electron beam evaporation method, respectively. Both the optical property and laser induced damage thresholds (LIDTs) at 1064 nm of Ta2O5 films on different substrates are investigated before and after annealing at 673 K for 12h. It is shown that annealing increases the refractive index and decreases the extinction index, and improves the O/Ta ratio of the Ta2O5 films from 2.42 to 2.50. Moreover, the results show that the LIDTs of the Ta2O5 films are mainly correlated with three parameters: substrate property, substoichiometry defect in the films and impurity defect at the interface between the substrate and the films. Details of the laser induced damage models in different cases are discussed.

A highly efficient light-trapping structure for thin-film silicon solar cells

A highly efficient light-trapping structure, consisting of a diffractive grating, a distributed Bragg reflector (DBR) and a metal reflector was proposed. As an example, the proposed light-trapping structure with an indium tin oxide (ITO) diffraction grating, an a-Si:H/ITO DBR and an Ag reflector was optimized by the simulation via rigorous coupled-wave analysis (RCWA) for a 2.0-mu m-thick c-Si solar cell with an optimized ITO front antireflection (AR) layer under the air mass 1.5 (AM1.5) solar illumination. The weighted absorptance under the AM1.5 solar spectrum (A(AM1.5)) of the solar cell can reach to 69%, if the DBR is composed of 4 pairs of a-Si:H/ITOs. If the number of a-Si:H/ITO pairs is up to 8, a larger A(AM1.5) of 72% can be obtained. In contrast, if the Ag reflector is not adopted, the combination of the optimized ITO diffraction grating and the 8-pair a-Si:H/ITO DBR can only result in an A(AM1.5) of 68%. As the reference, A(AM1.5) = 31% for the solar cell only with the optimized ITO front AR layer. So, the proposed structure can make the sunlight highly trapped in the solar cell. The adoption of the metal reflector is helpful to obtain highly efficient light-trapping effect with less number of DBR pairs, which makes that such light-trapping structure can be fabricated easily.

Passive Q-switching of diode-pumped Yb:YAG microchip laser with ion-implanted GaAs

We reported a passive Q-switched diode laser pumped Yb:YAG microchip laser with an ion-implanted semi-insulating GaAs wafer. The wafer was implanted with 400-keV As^(+) in the concentration of 10^(16) ions/cm^(2). To decrease the non-saturable loss, we annealed the ion-implanted GaAs at 500 oC for 5 minutes and coated both sides of the ion-implanted GaAs with antireflection (AR) and highreflection (HR) films, respectively. Using GaAs wafer as an absorber and an output coupler, we obtained 52-ns pulse duration of single pulse.

Antireflection coatings optimized for single-cycle THz pulses

We show that a single-layer antireflection coating on a THz source of high refractive index can substantially increase the transmission of emitted THz pulses. Calculations indicate that the optimum coating thickness depends on the exact shape of the generated THz waveform and whether the transmitted waveform is to be optimized for the highest peak (temporal) amplitude, peak spectral amplitude, or pulse energy. We experimentally demonstrate a 15% increase in peak amplitude, a 33% increase in peak spectral amplitude, and a 48% increase in energy for a 100 μm thick fused silica AR coating on a lithium niobate crystal used as THz emitter.

The highs (B1H) and lows (B1L) of human heart B1-adrenoceptors (AR)

The 1AR has two binding sites which can be activated to cause cardiostimulation. The first, termed, 1HAR (high affinity site of 1AR) is activated by noradrenaline and adrenaline and is blocked by relatively low concentrations of β-blockers including carvedilol (Kaumann and Molenaar, 2008). The other, termed, 1LAR (low affinity site of 1AR) has lower affinity for noradrenaline and adrenaline and is activated by some β-blockers including CGP12177 and pindolol, at higher concentrations than those required to block the receptor (Kaumann and Molenaar, 2008). (-)-CGP12177 is a non-conventional partial agonist that causes modest and transient increases of contractile force in human atrial trabeculae (Kaumann and Molenaar, 2008). These effects are markedly increased and maintained by inhibition of phosphodiesterase PDE3. The stimulant effects of (-)-CGP12177 at human β1ARs was verified with recombinant receptors (Kaumann and Molenaar, 2008). However, in a recent report it was proposed that the positive inotropic effects of CGP12177 are mediated through 3ARs in human right atrium (Skeberdis et al 2008). This proposal was not consistent with the lack of blockade of (-)-CGP12177 inotropic effects or increases in L-type Ca2+ current (ICa-L ) by the β3AR blocker 1 μM LY748,337 (Christ et al, 2010). On the otherhand, (-)-CGP12177 increases in inotropic effects and ICa-L were blocked by (-)-bupranolol 1-10 μM (Christ et al, 2010). Chronic infusion of (-)-CGP 12177 (10 mg/Kg/24 hours) for four weeks in an aortic constriction mouse model of heart failure caused an increase in left ventricular wall thickness, fibrosis and inflammation-related left ventricular gene expression levels. Christ T et al (2010) Br J Pharmacol, In press Kaumann A and Molenaar P (2008) Pharmacol Ther 118, 303-336 Skeberdis VA et al (2008) J Clin Invest, 118, 3219-3227

Gartner AR Process Modelling Movie

AR process modelling movie presented at Gartner BPM Summit in Sydney, August, 2011.