Energy transfer and excited state lifetime of some anthracene laser dyes

The lifetimes of some anthrathene derivatives in different solvents have been determined using the phase modulation method. The lifetime of 10-phenyl-2-methyl-9-acetoxyanthracene and 10-(4-acetoxyphenyl)-2-methyl-9-acetoxyanthracene were found to equal 11 and 11 ns in methanol, respectively. Energy transfer from 10-phenyl-2-methyl-9-acetoxyanthracene and 10-(4-acetoxyphenyl)-2-methyl-9-acetoxyanthracene to rhodamine B and rhodamine 110 in different solvents has been studied by using steady-state emission measurements. The large values of the critical transfer distance R₀ and the rate constant of energy transfer k_ET suggest that the mechanism is long-range dipole–dipole energy transfer as described by Förster.     

Workshop on gravitational waves and relativistic astrophysics

Discussions related to gravitational wave experiments viz. LIGO and LISA as well as to observations of supermassive black holes dominated the workshop sessions on gravitational waves and relativistic astrophysics in the ICGC-2004. A summary of seven papers that were presented in these workshop sessions has been provided in this article.     

Light power density distribution of image spot of laser triangulation measuring

HaiMing Wang [Wang HaiMing, Long range optical triangulation utilising collimated probe beam. Optics and Lasers in Engineering, 23(11), 1995, 41–52] studied the influences of the size of the object spot on the image spot in laser triangulation measuring. This paper points out that the study method of HaiMing Wang is inappropriate from two points of view. The size and relative power density distribution of the image spot can be calculated either when assuming the object spot is an ideal point, which emits a uniform spherical wave over the object, or when assuming that the object surface is a light scattering surface. Both the conditions show that the size of the image spot is much bigger than that of HaiMing Wang’s.     

利用激光激发原子荧光光谱方法分析海洋沉积物样品中的痕量钯

本文介绍了激光激发原子荧光光谱分析方法及实验谱仪装置，利用这套谱仪共对３６个我国东海大陆架沉积物样品中的钯进行了分析测量。     

相位型宽频带激光测振仪的研究

在理论上详细描述了一种新型的激光偏振移相干涉测振系统.通过计算机对两路正交干涉光电信号的接收和正弦逼近法数字处理,在1Hz～10KHz宽频带内测量振动台的振幅和初相位,从而实现加速度传感器复合灵敏度的绝对校准.运用琼斯矩阵证明干涉系统中通过偏振片调整可保证两信号的正交性.     

无创人皮肤浅表组织血液中卟啉的荧光光谱分析

人体中含有的卟啉化合物主要有血红蛋白、血红素、原卟啉、粪卟啉、尿卟啉等。健康状况影响卟啉代谢,恶性肿瘤影响原卟啉(PPⅨ)与类胡萝卜素的相对含量。采用钛宝石激光器、光导纤维、荧光探头、多色仪、CCD、微机,组建起实施人体皮肤浅表组织内血液中的卟啉进行无创荧光检测系统。对人耳垂皮肤浅表组织内血液进行了荧光分析,结果同P_pⅨ水溶液的荧光谱一致。     

Combinatorial discovery of anomalous substrate effect on the photochemical properties of transition metal-doped epitaxial SrTiO3 heterostructures

Epitaxial Sr(V_xCr_yTi_1−x−y)O₃ (0≤x+y≤0.05) ternary composition spreads were grown on two different single crystal substrates, LaAlO₃ and Nb-doped SrTiO₃, by use of combinatorial laser molecular beam epitaxy with a specially patterned slide masking plate. The photocatalytic activity on the composition spreads was evaluated by the photo-reduction of Ag⁺ in an AgNO₃ aqueous solution to deposit Ag metal on the spreads. The V-doping effect was found to depend greatly on the substrate: the photodeposition of Ag was much enhanced in the composition region of SrV_0.05Ti_0.95O₃ only on the Nb-doped SrTiO₃, but not on the LaAlO₃ and non-doped SrTiO₃.     

非线性放大环形镜“8”字腔光纤激光器实验研究

使用976 nm半导体激光器作为抽运源,对利用非线性放大环形镜（NALM）锁模运行的掺Yb3+光纤激光器进行了实验研究,获得了脉冲宽度43.6 ps,中心波长为1053.3 nm的锁模脉冲激光输出, 光谱宽度8 nm, 输出功率为0.2 mW, 重复频率为18.2 MHz, 经过放大, 通过光栅对腔外色散补偿,在腔外产生了宽度616 fs的脉冲激光.     

Excimer laser ablation of thin titanium oxide films on glass

Thin titanium dioxide films are deposited on glass substrates by magnetron sputter deposition. They are irradiated in air, by means of a KrF excimer laser. The ablation rate is measured as a function of the laser fluence per pulse, F, and of the number of pulses, N. Above a fluence threshold, the films are partially ablated. The ablated thickness does not vary linearly with N. This is the signature of a negative feedback between the film thickness and the ablation rate. The origin of this negative feedback is shown to be due to either thermal or electronic effects, or both. At high F, the film detachs from the substrate.     

ZrO2薄膜的改性与抗激光损伤研究

 采用水热合成技术，制备了ZrO₂胶体，用旋涂法镀制了单层ZrO₂介质膜以及添加了有机粘合剂PVP的复合ZrO₂-PVP薄膜。采用X射线衍射(XRD)、椭偏仪、红外分光光度计（FTIR）、原子力显微镜（AFM）等仪器对干凝胶及薄膜进行了性能测试和表征，并用输出波长为1.064 μm、脉宽为10 ns的电光调Q激光系统产生的强激光测试其激光损伤阈值。测得ZrO₂和ZrO₂-PVP薄膜在300 ℃热处理60 min后的激光损伤阈值分别为24.5 J/cm²和37.8 J/cm²。研究表明：添加有机粘合剂后的复合薄膜具有平整的表面结构；有机粘合剂的添加有助于提高薄膜的折射率和激光损伤阈值，其中，ZrO₂-PVP 复合薄膜的折射率可高达1.75，激光损伤阈值达到37.8 J/cm²，比ZrO₂单层膜的激光损伤阈值提高50%。