Influence of Radiative Irradiation on the Optical and Electrical Properties of Crystalline Quartz

The influence of radiation on the optical properties of quartz crystals has been investigated. Using the methods of IR and Raman spectroscopy, the lattice dynamics associated with a change in the spectral characteristics of a number of the stretching and deformation vibrations of the crystal lattice upon irradiation of samples by gamma quanta and neutrons to high doses has been determined. The regularities of radiative modification of the spectral characteristics of certain fully symmetrical and degenerate modes of the stretching vibrations of hydroxide groups are determined. To elucidate the reasons for the changes in the optical spectra, the latter were compared with the corresponding spectra obtained upon heating of wafers and with the change in the conductivity of crystals caused by irradiation. It is assumed that the changes in the optical spectra and conductivity of irradiated crystals are mainly due to the rearrangement of the quartz structure and to the stimulated migration of impurities. A possible mechanism of the process of conduction in the material is discussed in the framework of the existing models.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 224–229, March–April, 2005.     

γ-辐照对纯Y2SiO5和Eu3+:Y2SiO5晶体光谱性能的影响

研究了γ-辐照前后纯Y2SiO5和Eu^3＋掺杂的Y2SiO5晶体吸收光谱的变化,辐照后,未退火和氢气退火的纯Y2SiO5晶体在260-270nm和320nm波段产生了附加吸收峰,分别是由F心和O^-心的吸收引起的;经过空气退火的纯YSO晶体中,由于消除了氧空位,因此辐照后没有出现色心吸收峰。在Eu^3＋;Y2SiO5晶体中,不但有相同的F心和O心吸收峰,而且还有Eu^2＋离子在300nm和390nm的吸收峰。随着辐照剂量的增加,色心附加吸收峰增强。空气退火能减少Eu^3＋：Y2SiO5晶体中的色心,而氢气退火能增加色心。     

γ-辐照对纯Y_2SiO_5和Eu~(3+)∶Y_2SiO_5晶体光谱性能的影响

研究了γ-辐照前后纯Y2SiO5和Eu3+掺杂的Y2SiO5晶体吸收光谱的变化,辐照后,未退火和氢气退火的纯Y2SiO5晶体在260~270 nm和320 nm波段产生了附加吸收峰,分别是由F心和O-心的吸收引起的;经过空气退火的纯YSO晶体中,由于消除了氧空位,因此辐照后没有出现色心吸收峰。在Eu3+∶Y2SiO5晶体中,不但有相同的F心和O-心吸收峰,而且还有Eu2+离子在300 nm和390 nm的吸收峰。随着辐照剂量的增加,色心附加吸收峰增强。空气退火能减少Eu3+∶Y2SiO5晶体中的色心,而氢气退火能增加色心。     

Optical and Scintillation Properties of NaI(Tl) Crystals

Using absorption spectroscopy and luminescent methods, we have investigated qualitatively dissimilar NaI and NaI(Tl) crystals. It is established that in NaI(Tl) crystals grown under conditions of melt hydrolysis and interaction with the air components, centers of additional luminescence of nonactivation nature are formed that decrease the transparency in the activator-radiation region. Data on the hole nature of these centers are obtained. It is shown that high-temperature annealing can alter the number of centers responsible for the decrease in the transparency of the NaI(Tl) crystals.     

Gold and Silver Thin Film Analysis by Optical and Neutron Activation Techniques

Thicknesses of gold and silver thin films have been determined by NAA technique. Reasonable agreement with conventional optical method has been obtained, but the lower detection limit in the case of NAA is far better than in the optical method.

Es wurde die Dicke von Gold- und Silberfilmen mittels NAA-Technik bestimmt. Dabei konnte eine vernünftige Übereinstimmung mit der konventionellen optischen Methode erzielt werden, wobei im Falle der NAA die untere Nachweis grenze wescntlich besser war als vergleichsweise die optische Methode.     

薄膜厚度对AgInSbTe相变薄膜的光学性质的影响

采用射频溅射法制备了Ag8In14Sb55Te23相变薄膜,对深积态薄膜在300℃时进行了热处理,测量了不同厚度薄膜的反射、吸收谱及光学常数。研究了薄膜的光学常数与薄膜厚度的关系。结果表明在一定的厚度范围其光学常数随膜层厚度的不同有较大的变化,尤其在短波长范围内更为明显,这对于短波长记录相变光盘有重要意义。     

电子俘获材料的光学性质及光存储机制研究

报道在硫化锶中掺入Ｅｕ、Ｓｍ和Ｃｅ、Ｓｍ两种激活剂的具有良好的光存储功能的新型光子学材料。以紫外到绿光之间不同波长的光写入信息，用近红外光读出，读出信号为橙色或绿色发光。系统的光响应速率小于２０ｎｓ，写／读／擦速度快；光存储机制为电子的俘获和释放，无热效应，比目前的其他光存贮系统更优越。     

Optically Induced Effects in the Thermoluminescence of Dosimetric Anion-Defective Corundum Crystals

This paper considers the influence of light fluxes in the 200–600-nm spectral range on the thermally stimulated luminescence (TL) of TLD-500 radiation detectors based on anion-defective corundum crystals. It has been shown that the luminescent-storing action of light in the above spectral range is due to the optical ionization of F-centers and electronic trapping centers of carriers responsible for the dosimetric peak at 450 K and TL at higher temperatures. The features of the dosimetric information distortion depending on the initial state of population of deep traps and the spectral composition and power of optical radiation are discussed.     

单轴应变对氮化铟电子结构及光学性质的影响

采用密度泛函理论框架下的第一性原理平面波赝势方法,计算单轴应变下闪锌矿氮化铟的电子结构及光学性质.结果表明：施加应变会使带隙变窄.对于拉应变,随着应变增大带隙减小程度增大;对于压应变,随应变增大带隙减小程度减弱;且拉、压应变对带隙调控都是线性的.在能量区间4 eV~12 eV范围内施加应变时,氮化铟的吸收光谱发生红移,随拉应变程度增加,吸收光谱的红移进一步加大;随压应变增加,吸收光谱红移减弱;在该范围内,氮化铟的折射率、反射率随拉应变的增大而增加,随压应变增加减小;施加拉应变时能量损失函数峰值增大,施加压应变后能量损失函数峰值减小.通过施加单轴应变能有效调节氮化铟材料的电结构及光学性质.     

温度对生物组织模拟液光学特性影响的研究

采用牛奶作为生物组织的模拟液,研究温度变化对生物组织光学特性的影响。应用双积分球技术对牛奶在光波波长为1100~1700 nm、温度25~40℃范围内的光学参量进行了测量,分析光学参量随温度的变化规律。结果表明,温度对散射作用的影响比吸收作用更大,随温度的升高,约化散射系数具有明显减小的趋势。与25℃相比,40℃下的约化散射系数下降了约10%;而吸收率的变化趋势不明显且规律复杂。以上研究结果与公开发表的人体离体皮肤组织光学参量随温度变化的研究结果基本一致,从而为深入研究温度对生物组织光学测量的影响提供了理论和实践上的指导。     

Effect of Hydrostatic Pressure on Optical Properties of TlBr and TlCl

We present first principles calculations of optical properties of binary semiconductor compounds TlBr and TlCl.Dependences of dielectric function,reflectivity and refractive index on hydrostatic pressure are calculated using self-consistent scalar relativistic full potential linear augmented plane wave method(FP-LAPW) within a generalized gradient approximation(GGA).They are compared with previous calculations and experimental measurements.Good agreements are found.     

准一维深色纳米ZnO的水热方法生长及其结构和光学性能的调变

本文以高纯度金属锌箔为Zn和衬底,利用传统的水热合成方法制备了深色的纳米结构ZnO. 研究发现,改变制备温度可以调变ZnO样品的颜色和光学性能,尤其是提高温度可以显著地降低可见光波段太阳能的活性. 推测这种现象与ZnO纳米棒顶端的尖锥形貌密切相关,这种结构加剧了光在ZnO纳米棒之间的折射和反应. 改善ZnO的光吸收能力对于提升ZnO基太阳电池的效率有重要意义.     

应变对纤锌矿结构GaN电子结构及光学性质的影响

使用第一性原理密度泛函理论（DFT）框架下的广义梯度近似（GGA+U）方法计算单轴应变对纤锌矿结构GaN的键长、差分电荷密度、电子结构以及光学性质的影响.结果表明：带隙随应变的增加而减小,压应变在（-1%~-3%）范围内变化时带隙变化不明显,压应变超过3%时带隙随应变的增大显著减小.光学性质研究表明,应变对介电函数虚部峰的位置和大小都产生影响,静态介电常数随应变的增大而增大;应变使GaN的吸收系数减小.     

Fabrication and Gamma-Ray Irradiation Effect on Optical and Mechanical Properties of Germano-Silicate Glass Fibers with Inner Cladding of B and F Doped Silica Glasses

ABSTRACT

The effect of glass composition, pure silica glass, boron-doped and fluorine-doped silica glasses of inner cladding, in the germano-silicate glass core fibers on optical and mechanical properties upon the γ-ray irradiation was investigated. Enhanced radiation hardening at 1,550 nm was found in both the B- and F-doped fibers after the γ-ray irradiation with dose-rate of 1.25 kGy/h. The radiation-induced attenuation (RIA) was found to increase in the order of the B-doped fiber, the F-doped fiber, and the silica fiber. While no major influence on the refractive index of the fibers after the γ-ray irradiation was found, the residual stress was slightly changed.     

掺杂氧的Ge-Sb-Te相变薄膜的光学性质

研究了氧掺入Ge-Sb-Te射频溅射相变薄膜在400nm-800nm区域的光学常数（n,k）和反射、透射光谱，发现适当的氧掺入能大大增加退火前后反射率对比度，因此可通过氧掺入改良Ge-Sb-Te相变材料的光存储性能。     

立方型Ti-B-N的光学性质的计算

立方型TiBN材料的光学性质对于深刻理解TiBN薄膜材料的光学性质,以及监测和控制TiBN薄膜材料的生长过程起着重要作用。使用基于密度泛函理论的平面波超软赝势方法计算了立方型TiBN的电子结构和光学性质,给出了电子态密度、介电常数、吸收系数、反射力、折射系数、消光系数等计算结果,并对计算结果作了分析。态密度图显示,存在源于B的2p态的态密度峰,分析认为这对立方型TiBN的光学吸收造成了明显影响。同时还计算了立方型TiBN的色度坐标,并根据计算结果对工艺参量与TiBN薄膜材料色度坐标之间的联系作出了分析。     

蓝宝石中子辐照色心的研究

研究了中子辐照对蓝宝石(α-Al2O3)单晶体缺陷形成及光学性能的影响,对采用提拉法与温度梯度法生长的蓝宝石晶体进行中子辐照,通过对比辐照前后的吸收及荧光光谱变化,发现辐照使得蓝宝石晶体内形成F、F^ 和F2^ 色心缺陷,但不同方法生长的晶体样品中色心浓度差异明显。其中提拉法样品的F心浓度要高于温度梯度法样品,而温度梯度法样品中F^ 色心浓度要高于提拉法样品。分析表明,这与两种方法生长的晶体中杂质含量差异有关。通过研究辐照后晶体的热致发光谱发现提拉法与温度梯度法生长的蓝宝石晶体分别在145℃与150℃有明显的热致发光出现,采用初始上升法计算出两种方法生长的晶体的热致发光陷阱深度分别为1．15eV及1．05eV。     

单能中子源中低能成份对活化截面测量的影响

对用单能中子源作活化截面测量时低能中子干扰的影响作了分析研究,并从测量的两种常用中子源T(d,n)⁴He和D(d,n)³He的中子源能谱中验证了这种定性分析.最后给出了两个比较典型的反应⁵⁸Ni(n,P)⁵⁸Co和⁶⁴Zn(,P)⁶⁴Cu反应的截面测量结果.     

耦合结构有机微腔的光致发光特性

耦合光学微腔(Coupled optical microcavity,CMC)是一种特殊结构的微腔,在耦合微腔中,两个独立的微腔相邻耦合在一起.通常一个腔是无源的,另一个腔是有源的.首次研究了有机材料在耦合微腔中的自发发射特性.实验采用的有机发光材料为八羟基喹啉铝Tris(8-quinolinolato)aluminium(Alq₃),器件的结构为Glass/DBR_A/Filler/DBR_B/Alq₃/DBR_C.底部腔是无源的,组成为DBR_A/Filler/DBR_B.顶部腔是有源的,由DBR_B/Alq₃/DBR_C构成.其中反射镜DBR_A、DBR_B、DBR_C以及填充层(Filler)均由光学介质材料构成.通过结构设计使两个腔的谐振波长均位于530nm.耦合微腔器件与单层Alq₃薄膜相比较,Alq₃薄膜的光致发光光谱是峰值位于511nm的宽谱带,而在耦合微腔器件中观察到的是具有两个腔模式,峰值波长分别位于518,553nm的增强并窄化的光谱.这是由于两个腔的光场耦合引起了腔模式分裂.结果表明耦合微腔能极大地改变有机材料的自发发射特性,可以用来提高器件的发光效率.     

ZnO薄膜的光学性质研究

采用直流反应磁控溅射方法在玻璃基底上成功地淀积ｃ轴取向性好的ＺｎＯ薄膜。经过优化计算，获得并分析了不同氧分压下制备的ＺｎＯ薄膜的折射率ｎ和消光系数ｋ的数值；同时得到了吸收光学带隙Ｅｏｐｔ，用能带模型解释了Ｅｏｐｔ的变化规律。