Laser-induced damage of Ti O2 Si O2 high reflector at 1064 nm

A high laser-induced damage threshold (LIDT) TiO2/SiO2 high reflector (HR) at 1064 nm is deposited by e-beam evaporation. The HR is characterized by optical properties, surface, and cross section structure. LIDT is tested at 1064 nm with a 12 ns laser pulse in the one-on-one mode. Raman technique and scanning electron Microscope are used to analyze the laser-induced modification of HR. The possible damage mechanism is discussed. It is found that the LIDT of HR is influenced by the nanometer precursor in the surface, the intrinsic absorption of film material, the compactness of the cross section and surface structure, and the homogeneity of TiO2 layer. Three typical damage morphologies such as flat-bottom pit, delamination, and plasma scald determine well the nanometer defect initiation mechanism. The laser-induced crystallization consists well with the thermal damage nature of HR. (C) 2008 American Institute of Physics.

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.

Laser induced damage threshold at 355 and 1064 nm of Ta2O5 films of different phases

Ta2O5 films are deposited on fused silica substrates by conventional electron beam evaporation method. By annealing at different temperatures, Ta2O5 films of amorphous, hexagonal and orthorhombic phases are obtained and confirmed by x-ray diffractometer ( XRD) results. X-ray photoelectron spectroscopy ( XPS) analysis shows that chemical composition of all the films is stoichiometry. It is found that the amorphous Ta2O5 film achieves the highest laser induced damage threshold ( LIDT) either at 355 or 1064 nm, followed by hexagonal phase and finally orthorhombic phase. The damage morphologies at 355 and 1064 nm are different as the former shows a uniform fused area while the latter is centred on one or more defect points, which is induced by different damage mechanisms. The decrease of the LIDT at 1064nm is attributed to the increasing structural defect, while at 355nm is due to the combination effect of the increasing structural defect and decreasing band gap energy.

双奇核~(172)Re高自旋态实验研究

利用149Sm(27Al,4nγ)172Re反应布居了形变双奇核172Re的高自旋态,用12套带有BGO反康普顿抑制的高纯锗探测器阵列进行了在束γ实验测量,首次建立了172Re由3个转动带构成的高自旋态能级纲图.研究和讨论了3个转动带的结构特征,基于已有的高自旋态核结构知识并通过系统学比较和分析指出它们的准粒子组态分别为πh11/2 νi13/2,πh9/2 νi13/2和 π1/2-[541] ν1/2-[521].发现前两个转动带在自旋小于18时其转动能级呈现反常的旋称劈裂.

双奇核~(172)Re高自旋态转动带结构实验研究

利用重离子熔合蒸发反应 14 9Sm (2 7Al,4nγ) 172 Re布居了形变双奇核 172 Re的高自旋态 ,用 12套带有BGO反康普顿抑制的高纯锗探测器阵列进行了在束γ实验测量 ,首次建立了形变双奇核172 Re由 3个转动带构成的高自旋态能级纲图 .研究和讨论了 3个转动带的结构特征 ,基于已有的高自旋态核结构知识并通过系统学比较和分析指出它们的准粒子组态分别为πh11 2 νi13 2 ,πh9 2 νi13 2 和π1 2 -[5 41] ν1 2 -[5 2 1].发现前两个转动带在自旋小于 18.5时其转动能级呈现反常的旋称劈裂 .

双奇核~(172)Re的高自旋态；High Spin States in Odd-odd ~(172)Re

对149Sm(27Al,4n)172Re反应产生的172Re在束γ的实验数据进行了重新分析,新发现了可归属于172Re的3个转动带,由此建立了由6个转动带构成的172Re高自旋态能级纲图。依据相邻核的带结构知识和推转壳模型分析方法,对新发现的3个转动带的准粒子组态进行了指定,讨论了它们的转动特征。