用非简并泵浦探测方法研究C70/甲苯溶液的激发态吸收动力学

通过非简并的时间分辨泵浦探测技术对C70富勒烯/甲苯溶液的非线性光学性质进行了研究。在532 nm波长的皮秒激光脉冲泵浦下,用600 nm的皮秒激光脉冲测量了C70富勒烯的激发态非线性吸收动力学响应。利用五能级模型对实验结果进行了数值模拟,得到了非简并情况下C70富勒烯分子的光物理参数。实验结果表明:C70富勒烯在简并和非简并情况下的激发态寿命没有变化,但非简并情况下的单重态吸收截面要比简并情况下单重态吸收截面小。     

富勒烯在激光科学中的应用

简要评述了富勒烯在激光科学中的研究进展，介绍了富勒烯的非线性光学特性及其潜在应用，展示了富勒烯衍生物和掺富勒烯新型光学材料的研究与应用发展前景。     

富勒烯在激光科学中的使用

简要评述了富勒烯在激光科学中的研究进展，介绍了富勒烯的非线性光学特性及其潜在应有用，展示了富烯衍生物和掺富勒烯新型光学材料的研究与应用发展前景。     

有机铬富勒烯衍生物的激发态与光限幅特性

应用倍频ｎｓ／ｐｓＮｄ：ＹＡＧ脉冲激光系统,在波长为５３２ｎｍ,脉冲宽度为２１ｐｓ的条件下,研究了新型有机铬富勒烯衍生物的激发态吸收与光限幅特性,其光限幅特性优于富勒烯甲苯溶液;并应用单重态激发态吸收理论对实验结果进行了分析,实验结果与理论结果基本一致。     

激光照射下富烯稳定性的研究

本文研究了富勒烯固体在弱激光照射下随时间变化的拉曼光谱。结果表明，富勒烯固体在激光照射下随时间发生裂解形成石墨和无定形碳，同时发生了Ｃ６０的光致聚合效应。     

新型激活离子Cr^4＋的潜力和发展

Ｃｒ＾４＋作为激活中心离子的发现，填补了固体可调谐激光在近红外波段的空白，扩展了目前实用化固体激光的可调谐范围，在概括介绍Ｃｒ＾４＋离子特的基础上，提出了Ｃｅ＾４＋作为新型敏化离子的可能性；８００ｎｍ宽吸收带，易于二极管激光直接泵浦；宽增益谱，可产生超短飞秒ｆｓ脉冲，光通信、医疗两大领域为其开辟了广阔的应用前景。     

用紫外光直接在光纤内写入布拉格反射光栅的实验研究

用紫外光直接在光纤内写入布拉格反射光栅的实验研究杜卫冲谭华耀＊刘颂豪华南师范大学，激光生命科学研究所，广州５１０６３１＊香港理工大学，电机系自１９８９年Ｍｅｌｔａｚ［１］首次提出采用两束波长位于掺Ｇｅ－石英光纤吸收带内的相干紫外激光相干涉，从侧面照射...     

半导体激光器纵向泵浦准连续Cr∶LiSAF激光器的实验研究

用波长为653.2nm的半导体激光器实现了纵向泵浦Cr∶LiSAF激光器的准连续运转，晶体平均吸收功率为140mW时获得激光输出，在LD最大输出功率范围内，晶体平均吸收功率为680mW时，可获得最大平均输出功率32mW，斜效率5.6%.     

基于Er∶YAG单频可调谐激光器的甲烷吸收光谱测量

采用1.6μm激光差分吸收是探测甲烷(CH4)气体浓度的一种重要手段。通过对CH4气体吸收光谱的理论分析及计算,并基于Er∶YAG单频可调谐激光器,在实验室测量了CH4气体对1.645μm激光的吸收谱线。实验结果对研制用于测量CH4气体浓度的差分吸收激光雷达光源有重要意义。     

基于Er∶YAG单频可调谐激光器的甲烷吸收光谱测量

采用1.6μm激光差分吸收是探测甲烷(CH4)气体浓度的一种重要手段。通过对CH4气体吸收光谱的理论分析及计算,并基于Er∶YAG单频可调谐激光器,在实验室测量了CH4气体对1.645μm激光的吸收谱线。实验结果对研制用于测量CH4气体浓度的差分吸收激光雷达光源有重要意义。     

富勒烯有机溶液光致荧光研究

本文研究了C60、C70有机溶液的荧光效应,发现它们的Pyridine溶液在可见和紫外激光激发下有强而且宽的荧光峰,两种分子的吸收谱和荧光谱具有特殊的互补性,其混合物可以实现红绿蓝三色光致发光,体现了富勒烯在白光有机光致发光材料开发方面的潜在价值。     

Properties of Nd：YAG Laser with the Nonlinear Absorption of the Intracavity Fullerenes

ＰｒｏｐｅｒｔｉｅｓｏｆＮｄ：ＹＡＧＬａｓｅｒｗｉｔｈｔｈｅＮｏｎｌｉｎｅａｒＡｂｓｏｒｐｔｉｏｎｏｆｔｈｅＩｎｔｒａｃａｖｉｔｙＦｕｌｌｅｒｅｎｅｓ￥ＬＵＯＴｉｎｇ；ＹＵＺｈｅｎｘｉｎ（ＳｔａｔｅＫｅｙＬａｂｉｒａｔｏｒｙｏｆＵｌｔｒａｆａｓｔＬａ...     

掺富勒烯光学玻璃的吸收光谱

成功地将富勒烯掺入两种不同的高温光学玻璃，发现在可见光波段有较强的附加吸收带，同时，掺杂玻璃的本征吸收边端发生明显光移。     

Localization of electron density waves in a system of carbon nanotubes and fullerenes

An approach to investigation of electronic properties of fullerene-filled nanotubes is proposed within the Hubbard model. It is shown that absorption of nanotubes decreases when they are filled with fullerenes. A prediction is made that the electron wave packet may be localized on the inhomogeneities induced by the fullerenes inside the nanotubes.     

Effect of fullerenes on spectral and nonlinear optical properties of <Emphasis Type="Italic">N</Emphasis>-(4-nitrophenyl)-(<Emphasis Type="Italic">L</Emphasis>)-prolinol structure

The influence of fullerenes C₆₀ and C₇₀ on the optical characteristics of a promising organic system, N-(4-nitrophenyl)-(L)-prolinol (NPP), is studied. The UV and blue absorption bands are found that can be controlled by introducing fullerenes. These bands are caused by the change in the electronic structure of the organic system induced by fullerenes and indicate the presence of an ordering in the arrangement of macromolecules. The observed changes in the IR absorption result from the structural rearrangement of the system and may be related to a weak complexing between a donor fragment of the NPP molecule and fullerene. The effect of restriction of the nanosecond laser radiation at 532 nm is considered and characteristics of nonlinear transmission of laser radiation at 337 nm are presented. The levels of attenuation and incident energy are estimated, which determines the possibility of using results of these studies in the development of optical gates in a broad spectral range.     

Optical transmittance spectroscopy of concentric-shell fullerenes layers produced by carbon ion implantation

Concentric-shell fullerenes, also called carbon onions, produced by carbon ion implantation into silver thin films, and subsequently deposited on a silica substrate, were studied by optical transmission spectroscopy in the wavelength range 0.2 - 1.2 μm. In this interval, the strongest absorption is due to the π-plasmon of sp²-like carbon. The position of the plasmon absorption band clearly evolved from 265 nm at low fluence to 230 nm at high implantation fluences. A simulation of the optical spectra based on dielectric models of the concentric-shell fullerenes layer allowed us to identify the first peak as due to disordered graphite and the latter to the carbon onions. The concentration of residual graphite and the filling fraction of the carbon onions produced at high fluences could be estimated by fitting the optical spectra with computed transmittance curves. Received 13 July 2000     

Study of reverse absorption saturation in fullerene-containing polyimides

The effect of reverse absorption saturation is studied in aromatic polyimides sensitized with fullerenes and a dye. The power density is estimated at which these systems can be most efficiently used to limit the laser radiation power. The data obtained are explained within the framework of the Förster model.     

硼掺杂富勒烯储氢-从物理吸附到化学吸附的转变

本文采用密度泛函理论(DFT)中的局域密度近似(LDA)方法对硼(B)掺杂富勒烯(C_(35)B)储氢问题在前人的基础上做了进一步研究,结果表明被C_(35)B吸附的氢分子很容易解离,经历从物理吸附到化学吸附的转变,并且发现解离产物C_(34)BHCH有分子内氢转移反应发生,这时B原子仍能与氢分子有很强的相互作用,最终导致B位置以及与B最邻近的三个C原子上都有氢原子吸附.并利用过渡态理论从热力学上分析了这种反应的发生趋势.     

Low- and high-order nonlinear optical characterization of C60-containing media

Third- and higher-order nonlinear optical processes in fullerenes were studies to define the influence of low-order nonlinearities on the high-order harmonic generation in these media. We measured the nonlinear absorption coefficients of the C₆₀:toluene solution using the 532 and 1064 nm, 50 ps pulses. The high-order harmonic generation was studied during propagation of the 790 nm, 150 fs pulses through the plasmas produced on surfaces containing fullerene powder. These studies have shown that the low-order nonlinearities of fullerenes have no impact on the generation of harmonics in such mediums in the vacuum ultraviolet range at optimal intensity of laser radiation.     

Optical limiting with higher fullerenes

Optical limiting has been investigated for higher fullerenes and compared with C₆₀. The transmission through an aperture placed after solutions of C₇₆, C₇₈, and C₈₄ in tetrahydronaphthalene was measured using Q-switched laser pulses with a wavelength of 532 nm and a pulse width of 8 ns FWHM. Unlike C₆₀, the transmission for these higher fullerene solutions decreased linearly with increasing optical pulse energy. We attribute the linearized optical limiting response to self-defocusing of the optical beam and the absence of excited-state absorption. The ground state absorption spectra for the higher fullerenes suggest their use for optical limiting in the near infrared, and the C₈₄-tetrahydronaphthalene solution was found to be an optical limiter at 1.064 m.