Nonlinear two-photon absorption properties induced by femtosecond laser with the films of two novel anthracene derivatives

Two novel anthracene derivatives containing 4-vinylpyridine (FPEA) and 2-vinylpyridine (TPEA) poly(methyl methacrylate) films are prepared on quartz glass substrates. Their nonlinear absorption properties are investigated by using a 120-fs, 800-nm Ti:sapphire femtosecond pulsed laser operating at a 1-kHz repetition rate. The unique nonlinear absorption properties of these new compounds are observed by utilizing a Z-scan system. These two-photon absorption (TPA) properties are proven by the two-photon fluorescence excited at 800 nm. The FPEA and TPEA films have nonlinear TPA coefficients of 0.164 and 0.148 cm/GW and the TPA cross sections of 3.345 × 10-48 and 3.081 × 10-48 cm4 ·s/photon, respectively. The influence of the chemical structures on the nonlinear TPA properties of the compounds is also discussed. The highly nonlinear TPA activities of the films implied that the new anthracene derivatives are suitable materials with promising applications in super-high-density three-dimensional data storage and nano- or microstructure fabrication.     

四溴2,3-萘酞菁锌(Ⅱ)的合成及非线性光限幅特性

四溴萘酞菁锌;四溴2;3-萘酞菁锌(Ⅱ)的合成及非线性光限幅特性     

Low-Power Super-resolution Readout with Antimony Bismuth Alloy Film as Mask layer

Sb-Bi alloy flms are proposed as a new kind of super-resolution mask layer with low readout threshold power. Using the Sb-Bi alloy film as a mask layer and SiN as a protective layer in a read-only memory disc, the superresolution pits with diameters of 380 nm are read out by a dynamic setup, the laser wavelength is 780 nm and the numerical aperture of pickup lens is 0.45. The effects of the Sb-Bi thin film thickness, laser readout power and disc rotating velocity on the readout signal are investigated. The results show that the threshold laser power of super-resolution readout of the Sb-Bi mask layer is about 0.5 m W, and the corresponding carrier-to-noise ratio is about 20 dB at the film thickness of 50nm. The super-resolution mechanism of the Sb-Bi alloy mask layer is discussed based on its temperature dependence of reflection.     

Reversible Resistance Switching Effect in Amorphous Ge1Sb4Te7 Thin Films without Phase Transformation

We demonstrate a reversible resistance switching effect that does not rely on amorphous-crystalline phase transformation in a nanoscale capacitor-like cell using Ge1Sb4Te7 films as the working material. The polarity and amplitude of the applied electric voltage switches the cell resistance between low- and high-resistance states, as revealed in the current-voltage characteristics of the film by conductive atomic force microscopy （CAFM）. This reversible SET/RESET switching effect is induced by voltage pulses and their polarity. The change of electrical resistance due to the switching effect is approximately two orders of magnitude.     

纳秒单脉冲激光诱导AgInSbTe薄膜的相变特性

利用磁控溅射法在K9玻璃基底上制备了Ag8In14Sb55Te23(AIST)纳米薄膜,并利用激光抽运-探测技术测量了薄膜的时间分辨反射率变化特性。研究结果表明,在合适能量密度的单脉冲纳秒激光脉冲作用下,AIST薄膜可以快速从沉积非晶态转化为晶态结构,晶化过程包含中间熔化态。在较低能量密度范围内,反射率变化量和晶化时间都随能量密度变化呈线性增加趋势。     

A Feasible Approach to Optical--Electrical Hybrid Data Storage Using Phase Change Material

We present our experimental results supporting optical-electrical hybrid data storage by optical recording and electrical reading using Ge2Sb2Te5as recording medium. The sheet resistance of laser-irradiated Ge2Sb2 Te5 films exhibits an abrupt change of four orders of magnitude （from 107 to 10^3 Ω/sq） with increasing laser power, current-voltage curves of the amorphous area and the laser-crystallized dots, measured by a conductive atomic force microscope （C-AFM）, show that their resistivities are 2. 725 and 3.375 × 10^-3 Ω, respectively, the surface current distribution in the films also shows high and low resistance states. All these results suggest that the laser-recorded bit can be read electrically by measuring the change of electrical resistivity, thus making opticalelectrical hybrid data storage possible.     

一种新的芴类衍生物的三光子吸收诱导荧光和光限幅效应研究

通过对新合成的芴的一种具有对称性衍生物4-2-(7-(4-氨基苯乙烯基)-9，9-二(2-乙基己基)-9H-芴-2-)乙烯基)苯胺(BASF)的DMF溶液的研究，发现其具有很强三光子吸收频率上转换荧光发射特性，实验测出上转换荧光的波长范围是456—775nm，在510nm处的荧光强度与入射光强的三次方成正比.在0.03mol/L的浓度下就有明显的三光子吸收诱导的光限幅效应.非线性吸收系数和吸收截面分别为γ=4.34×10^-20cm³/W²和σ₃＝2.4×10^-39cm⁶/W². 关键词： 三光子吸收 光限幅 上转换荧光 吸收截面     

Two- and three-photon absorption in a novel fluorene-based compound

A novel symmetrical charge transfer fluorene-based compound 2,7-bis (4-methoxystyryl)-9, 9-bis (2-ethylhexyl)-9H-fluorene (abbreviated as BMOSF) was synthesized and its nonlinear absorption was investigated using two different laser systems: a 140-fs, 800-nm Ti:sapphire laser operating at 1-kHz repetition rate and a 38-ps, 1064-nm Nd:YAG pulsed laser operating at 10-Hz repetition rate, respectively. Unique nonlinear absorption properties in this new compound were observed that rise from multiphoton absorption. The nonlinear absorption coefficients were measured to be 6.02×10-3 cm/GW (due to two-photon absorption, exciting wavelength is 800 nm) and 3.6×10-20 cm3/W2 (due to three-photon absorption, exciting wavelength is 1064 nm). This new compound possesses strong fluorescence induced by two-photon absorption and obvious three-photon absorption optical limiting effects.     

反式和顺式-1,2-二氰-(4-乙基苯)乙烯结构的谱学分析

合成了2种新型的可溶性四氮杂卟啉中间体:反式-1,2-二氰-(4-乙基苯)乙烯和顺式-1,2-二氰-(4-乙基苯)乙烯.通过UV-Vis,FTIR,GC/MS,1H NMR等方法对这2种化合物的结构进行了表征,给出了它们完整的结构信息.分析比较了顺、反异构体结构上的差异,分析两者的紫外-可见光谱(UV-Vis)、红外光谱(FTIR)和核磁共振光谱(1H NMR)谱图的差异及其产生原因.     

八烷氧基2,3-萘酞菁锌(Ⅱ)的合成及荧光光谱研究

采用在强有机碱１，８－二氮杂双环［５，４，０］＋－－７烯（简称ＤＢＵ）存在下的醇溶剂中，由“分子碎片”与锌盐通过模板反应的新方法合成了一组八烷氧基２，３－萘酞菁锌配合物（Ｚｎ（ＲＯ）８ＮＰｃ，其中Ｒ＝Ｃ４Ｈ９、Ｃ８Ｈ１７、Ｃ１２Ｈ２５，ＮＰｃ＝Ｃ４８Ｈ１６Ｎ８）。产物进行了元素分析和红外光谱分析，并研究了它们在不同溶剂中的荧光光谱。