飞秒激光在KCl晶体中诱导色心

分别利用1kHz和200kHz两种重复频率的近红外飞秒激光,经过低数值孔径的物镜聚焦,空间选择性地辐照KCl晶体,在KCl晶体内部诱导出了一系列色心缺陷。通过飞秒激光辐照前后KCl晶体的吸收光谱分析,明确了飞秒激光照射后KCl晶体内部5种色心的归属,发现色心的浓度随着飞秒激光功率的升高而增长。对吸收光谱的分析表明,两种重复频率的飞秒激光所诱导的色心吸收带相应的峰值略有偏移。认为这是由高重复频率的飞秒激光的热累积效应引起的。理论分析表明,KCl晶体内部的点缺陷和高功率密度飞秒激光与KCl晶体相互作用所诱导的多光子吸收是色心形成的主要原因。     

化学掺杂法对KCl单晶的强化研究

本文介绍用化学掺杂的方法强化KCl单晶的实验研究。根据晶体在实际应用中的要求,规定了掺杂晶体的测试指标,选定了最佳杂质和掺量。为解决杂质分布的均匀性问题,改进了生长工艺,达到预定的各项指标。     

KCl:Li FA(Ⅱ)色心激光晶体材料(综述)

本文以KCl:Li FA(Ⅱ)心为色心激光材料的代表,从材料物理化学的角度分析了KCl-LiCl以及与基质KCl有关的掺杂体系的性质,综述了掺Li+KClFA(Ⅱ)心的主要特性,总结色心激光晶体的制备.     

铝酸钇单晶的色心

自从1969年掺钕的铝酸钇(YAP:Nd~(3+))晶体实现受激发射以后,它的研究与应用开始受到了重视。在国外,生长这类晶体都采用射频感应加热,使用铱坩埚和惰性或氧化气氛。所得的晶体都有色心,当不掺钕时,纯的YAP与纯的LaAlO_3晶体都呈茶色或黄棕色;当掺钕时(YAP:Nd~(3+))为樱桃红色。资料[3]认为LaAlO_3的色心可在     

色心和色心激光的发展

色心的激射功能是德国人B.Fritz和EMenke两人于1965年首先发现的。当时,他们对一根含有10~(16)个/厘米~3F_A心的(掺Li)KCl晶体棒(6×30毫米),用氙闪光灯进行泵浦,观察到晶棒产生2.7微米的红外激光发射,能量转换效率为0.1％。但由于色心物理学和量子电子学这两个领域之间的研究人员彼此缺乏联系,互不了解,故之后很长一段时间内无人问津。直到1974年,美国贝尔实验室的L.F.Mollenuear和D.H.     

KCl:Na晶体中的激光工作色心F_B(Ⅱ)

采用附加着色法,在KCl:Na晶体中获得密度为10~(16)～10~(18)厘米~(-3)的F心。利用F带光进行转型,得到了FB(Ⅱ)激光工作色心,其77K荧光发射带在2.1～2.8微米,峰值位置为2.5微米。     

热锻红外激光窗口材料KCl的显微结构

卤化物,特别是KCl被认为是高功率激光窗口最佳候选材料。为了研究热锻KCl的显微结构稳定性,用化学浸蚀法显示了晶粒间界并用光学显微镜进行了观测。在KGl多晶中发现有重结晶不完全、二次再结晶、不均匀的显微结构及室温下晶粒长大等现象。     

NaCl、KCl单晶研制成功

NaCl、KCl单晶作为激光器窗口材料,其光学性能十分优异。四川省自贡市化工研究所研制出的这两种单晶材料,经有关单位使用,效果良好。1978年12月19日至20日,四川省科委在自贡召开了红外材料NaCl、KCl单晶技术鉴定会。会议听取了自贡市化工研究所关于NaCl、KCl单     

色心激光晶体

本文报导近年来我们对碱卤晶体中色心研究的若干进展。主要内容有:(1)掺二价金属离子的NaF晶体中(F_2~+)心的一个可能的模型。(F_2~+)心可表示为一个F_2~+心位于一个正空位和二价金属离子的近邻(即F_2~++Ⅰ-Ⅴ对)。光谱学和热释发光的许多证据支持此种模型;(2)LiF晶体中F_3~+心的光学性质。对LiF晶体采用适当的着色条件,可得到比F_2     

碱卤色心晶体激光研究的新进展

本文提出了碱卤色心晶体激光综合研究的结果，比较详细地介绍了碱卤色心晶体生长研究、几种类型色心的特性，色心激光输出性能以及色心热光稳定性研究的新进展。     

RbCl:Li color center laser with laser diode pumping

CW operation of a RbCl:Li-F_A(II) laser has been obtained under pumping by a red laser diode. Pump power at threshold is 90 mW. Single frequency operation of the color center laser has been achieved. The intensity noise generated by two pump sources (laser diode and Kr-ion laser) is compared     

Single-frequency, single-knob tuning of a CW color center laser

We describe a simple way to achieve CW single-frequency laser operation with a grating as the sole tuning element. It is Shown, both experimentally and theoretically, that by proper choice of cavity parameters, the competing hole burning modes can be completely suppressed. Experiments to demonstrate the theoretical calculations were carried out in a CW color center laser using Tl⁰(1) centers. Linewidths of 0.01 cm^-1were obtained and this figure can probably be much improved by proper cavity stabilization. The method can be readily extended to any compact gain medium.     

Preparation and properties of GeS2 single crystals

Single crystals of GeS₂ are grown by two methods: crystallization from a melt and chemical vapor transport. All crystals are found to have a monoclinic structure with the unit-cell parameters a=11.45 Å, b=16.09 Å, c=6.7 Å, and β=91°. The reflection and transmission spectra are measured in the region of the absorption edge. The gap width is found to be equal to 3.2 eV.     

Preparation and optical properties of Co-doped ZnSe single crystals

ZnSe single crystals doped via Co diffusion are investigated. The diffusion was carried out from metal Co in He or Ar atmosphere. The spectra of optical density in the wavelength range 0.4–2 μm are investigated. It is found that the absorption edge shifts as the concentration of doping impurities increases. This shift is caused by the formation of the Zn_{1 ? x} Co_xSe alloy. The diffusion profile of the Co dopant is determined via measurement of the relative optical density of the crystals in the visible spectral region. The Co diffusivities (D) in the ZnSe crystals at T = 1103–1273 K are calculated. The analysis of the temperature dependence D(T) made it possible to determine the coefficients in the Arrhenius equation, namely, D ₀ = 3.4 × 10⁶ cm²/s and E ₀ = 3.8 eV.     

Fullerene single crystals as adsorbents of organic compounds

The results of investigations of the adsorption properties of fullerenes are presented. Fullerenes acting as adsorbents are compared with soot and activated carbon. From its adsorption properties, soot is similar to activated carbon. Fullerenes do not manifest themselves in the composition of soot material. As an independent adsorbent, fullerenes are considerably more effective than activated carbon. Possible mechanisms of fullerene adsorption are discussed. It is concluded that the adsorptivity of fullerenes is realized mainly through dispersion interactions. Certain theoretical estimates are presented.     

LiF晶体F_2色心可调谐激光器

本文报导以0.53微米激光作为泵浦的LiF:F_2色心可调谐激光器。实验所用的晶体的F_2心浓度约为6.2×10~(17)厘米~(-3),高于已有报导值。0.69微米附近可调谐激光输出线宽为1.5埃,能量转换效率为2.9％。晶体在连续运转6千个脉冲后,才开始出现漂白效应。     

Preparation and optical properties of the co-doped ZnTe single crystals

The ZnTe:Co single crystals are obtained by diffusion Co-doping. The spectra of optical density in the range of 2.4–0.38 eV are investigated. It is found that Co-doping of the crystals shifts the absorption edge to the low-energy region. The similarity of optical absorption spectra of the ZnTe:Co and ZnS:Co crystals is established. The observed absorption lines of ZnTe:Co are attributed to the optical transitions of electrons from the level of the ground state ⁴ A ₂(F) of the Co²⁺ ion to the levels of excited states ⁴ T ₁(P), ⁴ T ₁(F), and ⁴ T ₂(F) split by the spin-orbit interaction.     

Uranium-doped calcium fluoride as a laser material

Spectroscopic studies have shown that, apart from a set of absorption lines due to tetravalent uranium, U :CaF2crystals exhibit two types of U³⁺sites. An energy level system has been determined for the sites corresponding to "isolated" ions. These sites give rise to a maser transition at 2.51 microns. The second type of site, appearing only in more highly doped crystals, was associated with the maser lines observed at 2.61 and 2.57 µ. The 2.61-µ line arises from a "four-level" system of energy states and has been made to oscillate continuously. The 2.57-µ line is a high temperature line that has only been briefly studied. The intensity of the "isolated ion" spectrum saturates as the uranium concentration is raised, while that of the "high concentration" spectrum increases roughly quadratically with increasing uranium content. Longitudinal modes have been seen in the spectra of the maser outputs at both 2.51 and 2.61 µ Both lines exhibit spiking down to helium temperatures. In a crystal exhibiting both maser lines simultaneously, maser oscillation begins at a much lower threshold for the 2.61-µ line, but the output at this wavelength saturates at high excitation levels; this saturation has not been observed in the 2.51-µ line.