氮分子激光照射增大了LiF:F_3~+心浓度

在液氮温度下采用氮分子激光(337nm)照射已着色的LiF晶体,能有效地产生高浓度的F_3~+心.文中详细地描述了着色LiF晶体中F_3~+心的产生方法、光谱特性及其形成机理.     

着色KC1和KBr晶体色心的光谱特性及其零声子跃迁

详细研究了不同温度下着色ＫＣｌ晶体Ｒ２心和７５６．６ｎｍ零子声线以及着色ＫＢｒ晶体Ｒ２心零声子线的产生。利用恰当的热处理，可产生和增强零声子线，并给出了相应的物理解释。     

着色KCl和KBr晶体色心的光谱特性及其零声子跃迁

详细研究了不同温度下着色ＫＣｌ晶体Ｒ２心和７５６．６ｎｍ零声子线以及着色ＫＢｒ晶体Ｒ２心零声子线的产生．利用恰当的热处理，可产生和增强零声子线，并给出了相应的物理解释．     

NaF和NaF：Mg^＋＋晶体色心光致电离研究

用337nm、380nm和510nm脉冲激光照射着色NaF和NaF:Mg~(++)晶体,皆能产生大量F_2~+心.在照射过的NaF:Mg~(++)晶体中,观测到了F_2~+ 心向(F_2~+)~*心的转型现象.     

NaF及其掺杂晶体F2心的二向色性研究

给出了ＮａＦ及其掺杂质Ｌｉ＾＋、Ｍｇ＾２＋、Ｃｕ＾２＋和ＯＨ＾－五种样品的Ｆ２心在偏振的氮分子激光照射下的二向色性吸收特性，对各种样品中Ｆ２心的转向效率进行了比较，并对结果进行了机理性的分析。     

一种基于密度泛函理论计算晶体结合能的变分法

提出了一种基于密度泛函理论计算晶体结合能的变分法，利用该方法初步计算了ＬｉＦ、ＮａＦ、ＫＦ、ＬｉＣｌ、ＮａＣｌ和ＫＣｌ这六种典型离子晶体的结合能、平衡晶格常数和体弹性模量，与实验结果进行了比较，分析了存在的问题，并指出了与其它同类方法相比该方法的优点     

毛细管中柱对称类面心结构胶体晶体的光谱特性

用体积浓度为30% 的低分散二氧化硅小球悬浮液注入毛细管中自组织生长成胶体晶体. 实验测量了这种胶体晶体的透射谱. 测量结果显示这种胶体晶体的透射谱的柱对称性. 在垂直毛细管轴向的平面内，谱带结构不随光的入射角度变化，测得光谱在径向转360°保持不变. 在含毛细管轴的平面内，在与毛细管轴向夹角越小的方向，谱带越紫移；在垂直毛细管轴方向有最红的带隙. 测量得的光谱结果表明这种毛细管内的胶体晶体结构是柱对称的, 胶体晶体中密排面平行于毛细管的管壁. 另外，此柱对称的胶体晶体比低浓度制作的体心胶体晶体稳定. 这种轴向对称性的光子带隙特性将带来许多潜在的应用. 关键词： 光子晶体 胶体晶体 光子带隙 透射光谱 毛细管     

基于光纤-胶体晶体的液体折射率传感实验研究

制备了胶体晶体,并利用胶体晶体的光子带隙对折射率传感进行了实验研究。从理论上分析了胶体晶体光子带隙中心波长的变化与折射率的关系。通过设计模具制备了胶体晶体-光纤结构,用扫描电镜对胶体晶体的表面进行了观察,并测量了胶体晶体的光子带隙的位置。结果表明胶体晶体的光子带隙的测试结果与理论分析相一致。设计了实验装置,利用光纤间的耦合对胶体晶体的光子带隙的变化进行了测试和分析。结果表明SiO2胶体晶体光子带隙的中心波长为1445.5nm,且在不同折射率液体环境下,其中心波长发生移动,能够形成新的传感机理。对胶体晶体在液体传感上的应用进行了探索。     

提高PbWO4晶体光学性能的研究

钨酸铅（ＰｂＷＯ４）晶体在生长过程中由于缺氧产生了氧空位缺陷和Ｆｅ＾２＋杂质缺陷，使晶体着色，光学性能下降，在晶体生长过程中掺进Ｓｂ２Ｏ３，能消除氧空位，将Ｆｅ＾２＋氧化为无色的Ｆｅ＾３＋，较大幅度地提高ＰｂＷＯ４晶体的光学性能和闪烁性能。     

Ce：Fe：LiNbO3晶体光衍射效应的研究

减小Ｃｅ：Ｆｅ：ＬｉＮｂＯ３晶片的厚度，扩大泵浦光束直径，时由光爬行应晶体产生衍射自增强。单光束辐照Ｃｅ：Ｆｅ：ＬｉＮｂＯ３晶体时，出现变偏振现象等各向异性自衍射。本文对上述现象的形成机理进行了探讨。     

F-Zentren und Kolloide in der amorphen,hexagonalen und kubischen Phase von LiJ

By simultaneous evaporation of LiI and Li onto a cooled substrate F centers can be produced in the hexagonal (78 K<T _K <200 K) and amorphous (T _K <78 K) phase of one and the same salt. In both modifications there exist two types of centers F and F^*. The F^* center differs from the cubic F center (T _d -symmetry) by a nearby Frenkel defect. In hexagonal films the normal F band peaks at 2.58 eV, whereas the transitions of the F^* center appear at 2.92 and 2.58 eV too. Polarized irradiation at 20 K causes a dichroic behaviour of the F^* centers. Both types of centers can be transformed into one another photochemically. In the amorphous phase all transitions are shifted to lower energies by about 0.1 eV. After the phase change amorphous→hexagonal the absorption bands shift back by the same amount of energy. AboveT _K =230 K the excess metal forms colloids. The absorption bands are due to colloidal centers embedded in the crystalline material (2.25 eV) and films adsorbed to the crystallites (3.1 eV), respectively. By annealing a particle growth can be observed. After electrolytic colouration cubic single crystals of LiI exhibit an absorption band peaking at 2.36 eV. However, it is not yet sure, if this band is allowed to be ascribed to F centers.     

A study of M center formation in additively colored KCl

Additively colored crystals of KCl were cooled rapidly from a high temperature and then exposed to light absorbed by the F band. The rate of growth of the M band was initially low and increased markedly during the first part of the irradiation giving rise to what is called a “delay period” in the M center formation. During this delay period it was observed that 1. the quantum efficiency of F center fluorescence decreases by a factor of 3 or 4, and 2. the ability to convert F centers to F′ centers is reduced by about a factor of 3. These effects are interpreted as arising because of an appreciable decrease in the average nearest neighbor F center separation during this period. Results are also presented concerning the kinetics of M center formation, oscillator strengths of the M center transitions, the degree of polarization of the M center fluorescence, and the transfer of energy from an excited F center to an M center.     

Photothermal bleaching of Ca colloids in additively colored CaF2

Cation colloidal particles in additively colored CaF₂ crystals have been bleached with light in the colloidal band. At 360 K the colloid band decreases and a new band in the near i.r. region is created which is probably due to highly coagulated F-centers. At 430 K the colloidal band is destroyed at the same time that a band appears at 383 nm. This band has been tentatively associated to a kind of F-center. Photochromic conversions between colloids and i.r. bands at 360 K and between colloids and 383 nm band at 430 K have been obtained. A mechanism for the bleaching of colloids has been proposed.     

NaCl（OH－）中K~＋对F＋2型心的形成及其光谱性质的影响

研究了Ｋ＋对ＮａＣｌ（ＯＨ－）中（Ｆ＋２）Ｈ心的形成及其光谱性质的影响。结果表明，Ｋ＋的存在抑制了Ｆ＋２型心的形成，改变了（Ｆ＋２）Ｈ心的光谱性质，拓宽了发射谱的半功率谱宽。从而修正了Ｐｏｌｏｃｋ的实验结果。同时指出，研制具有更宽波长发射范围的Ｎａ１－ｘＫｘＣｌ（ＯＨ－）复合基质Ｆ＋２型色心激光材料是可能的     

LiF∶F2晶体中实现三维光数据存储的实验研究

基于LiF∶F2晶体在近红外飞秒脉冲激光作用下产生F2色心向F+3色心的转变,以及两种色心荧光光谱的不同,实现了荧光反射共焦读出和多光子写入的三维光数据存储的原理性实验.钛宝石再生放大器输出的脉冲宽度100 fs、中心波长800 nm、重复频率1 kHz的超短脉冲激光束,用数值孔径0.68的显微物镜聚焦到LiF：F2晶体内部,通过移动晶体实现了三维逐位式数据写入；用405 nm的连续蓝光激发存储位,通过探测F+3色心产生的540 nm荧光,实现了对信息位进行快速非破坏性的反射共焦读出.与多光子三维存储的透射共焦散射读出和相衬读出相比,格式与现存光盘技术兼容,结构简单；更重要的是,存储信息位是依靠荧光光谱的变化,折射率变化很小,可以有效增加读出层数.     

Farbzentren und Kolloide in abschreckend kondensierten Schichten von NaJ,CaF2 und SrCl2

By a simultaneous evaporation of NaI with excess alkali or alkaline earth metal onto a cooled substrate (T _K =20–150 K) highly disordered thin films are produced, which contain electron excess centers up to a concentration of more than 10²⁰ cm^?3. A complex optical absorption band peaking at 600 and 530 nm is found. The 600 nm band is mainly due to unperturbed F centers, whereas the 530 nm band is ascribed to perturbed F centers, whose symmetry is lowered to C_3v by a nearby Frenkel defect. Another optical transition of this F* center appears at about 600 nm in the dichroic spectrum, which is induced by polarized illumination at 20 K. The transition energies of the F* center are calculated by means of a semi-continuum model. A photochemical transformation of F* and F centers into one another is possible at 20 K. AboveT _K =220 K the excess metal is forming colloidal centers. Two absorption peaks at about 600 and 400 nm, respectively, are ascribed to different colloids, which are either embedded in the crystalline material (600 nm) or only adsorbed to the crystallites (400 nm). By annealing up to 350 K a particle growth and transformation take place. Amorphous quenched films of CaF₂ and SrCl₂ with excess alkaline earth metal reveal mainly colloidal absorption (except a weak F band in CaF₂). The colloids disappear by annealing above 150 K. This is believed to be closely connected with the crystallisation of the films.     

Photoconductivity and conductivity during photochemical conversion of F centers in hot potassium chloride crystals

A study was made of the electrical conductivity and photoconductivity of colored KC1 crystals during photochemical and thermal conversion of F centers into X centers at 250–300 °C and during the opposite conversion. A correlation is established between the time dependences of the photoconductivity and optical absorption at the F-band maximum. Stimulated dark conductivity is found during the forward photochemical reaction. The results confirm the earlier suggestion that the X centers are not colloidal, but smaller molecule-like aggregates of F centers bound to the matrix lattice and requiring an ionic mobility for their formation and destruction.Translated from Izvestiya VUZ. Fizika, No. 7, pp. 87–93, July, 1970.     

Photoionization processes in F aggregate centres of LiF crystal

Extensive studies have been carried out on the optical conversion of F and F-aggregate colour centres produced in lithium fluoride single crystal on gamma irradiation. Using 308 nm XeCl laser it has been shown that significantly large population build-up of F ₃ ⁺ centre and reduction in the population of undesirable F₂ centres can be achieved in gamma irradiated crystal at room temperature due to multistep photoionization processes. These and other investigations have provided a scheme for possible laser action based on F ₃ ⁺ colour centres in LiF crystal at room temperature.     

X射线辐照后BaFC1中缺陷性质的研究

未掺Eu2+的BaFCl粉末样品在80K下经X射线辐照后,在不同的温度条件下(从80K副273K),用580nm的光波激励样品时观测到310nm和380nm的发光峰.经分析认为,样品经X射线辐照后,在晶体中形成两种卤素离子的F-H''心对.当用F心吸收带的光波激励样品时,两种F—H心对衰变成相应的自陷激子态并复合发光.310nm和380nm分别对应于F-离子和Cl-离子的自陷激子的发光,并且它们的发光强度强烈地依赖于温度的变化。