共查询到20条相似文献,搜索用时 15 毫秒
1.
Domas Paipulas Viačeslav Kudriašov Mangirdas Malinauskas Valerijus Smilgevičius Valdas Sirutkaitis 《Applied Physics A: Materials Science & Processing》2011,104(3):769-773
We report studies of the modifications induced inside lithium niobate and KDP crystals by Yb:KGW ultrafast laser pulses, having
300-fs pulse duration and operating at 100-kHz repetition rate. By focusing the laser beam with a 0.42 numerical-aperture
objective, we have recorded homogeneous volume Bragg gratings in the bulk of the niobate crystal that showed excellent diffraction
efficiencies, reaching up to 87%, and remained permanent after thermal annealing for one hour at 150°C. The refractive index
modification level was found to be 0.002 in lithium niobate. The results show that lithium niobate is a very promising crystal
candidate for microphotonics applications. On the contrary, in the KDP crystal no smoothly modified refractive index zones
were created. 相似文献
2.
V. P. Dresvyanskiy M. A. Moiseeva A. V. Kuznetsov D. S. Glazunov B. Chadraa O. Bukhtsoozh B. Zandan N. Baasankhuu E. F. Martynovich 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(1):85-88
The release of energy in the form of the light sum of thermally stimulated luminescence (TSL), stored under conditions of self-focusing and the multiple filamentation of femtosecond laser radiation during the interaction between model wide-bandgap dielectric crystals of lithium fluoride is studied. It is shown that F2 color centers are important centers of emission in the TSL process. 相似文献
3.
Because of their extremely high instantaneous powers, femtosecond lasers can color many nominally transparent materials. Although the excitations responsible for this defect formation occur on subpicosecond time scales, subsequent interactions between the resulting electronic and lattice defects complicate the evolution of color center formation and decay. These interactions must be understood in order to account for the long-term behavior of coloration. In this work, we probe the evolution of color centers generated by femtosecond laser radiation in potassium chloride and potassium bromide single crystals on time scales from microseconds to hundreds of seconds. By using an appropriately chosen probe laser focused through the femtosecond laser spot, we follow the changes in coloration due to individual or multiple femtosecond pulses and the evolution of that coloration for long times after femtosecond laser radiation is terminated. 相似文献
4.
We observe electric pulses generated in sillenite crystals (Bi12SiO20 and Bi12TiO20) by 100-fs laser pulses at the wavelength of 400 nm (below the band gaps of both crystals). The peak value of the current
pulses scales linearly with the intensity of laser pulses up to ∼45 GW/cm2. The direction of the induced current depends on the polarization state of the laser pulse. This polarization dependence
and features of the current detection via charge accumulation at the sample electrodes allow us to conclude that the electric
pulses are generated due to the linear photogalvanic effect. 相似文献
5.
Korte F. Serbin J. Koch J. Egbert A. Fallnich C. Ostendorf A. Chichkov B.N. 《Applied Physics A: Materials Science & Processing》2003,77(2):229-235
Detailed investigations of the possibilities for using femtosecond lasers for the nanostructuring of metal layers and transparent
materials are reported. The aim is to develop a simple laser-based technology for fabricating two- and three-dimensional nanostructures
with structure sizes on the order of several hundred nanometers. This is required for many applications in photonics, for
the fabrication of photonic crystals and microoptical devices, for data storage, displays, etc. Measurements of thermionic
electron emission from metal targets, which provide valuable information on the dynamics of femtosecond laser ablation, are
discussed. Sub-wavelength microstructuring of metals is performed and the minimum structure size that can be fabricated in
transparent materials is identified. Two-photon polymerization of hybrid polymers is demonstrated as a promising femtosecond
laser-based nanofabrication technology.
Received: 20 November 2002 / Accepted: 20 January 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +49-511/2788-100, E-mail: ch@lzh.de 相似文献
6.
Yukun Han Xinwei Lan Tao Wei Hai-Lung Tsai Hai Xiao 《Applied Physics A: Materials Science & Processing》2009,97(3):721-724
We report the fabrication of surface enhanced Raman spectroscopy (SERS) fused silica glass substrates using fast femtosecond-laser
(fs-laser) scan, followed by silver chemical plating. A cross-section enhancement factor (EF) of 2.5×106, evaluated by Rhodamine 6G (10−7 M solution), was obtained. The Raman mapping indicated a good uniformity over the fs-laser scanned area. The dimension and
pattern of the SERS activated region can be conveniently controlled by laser 2D scanning, potentially enabling integration
of SERS into a high-order optical–chemical analysis system on a glass chip. 相似文献
7.
Modification of the fused silica glass network associated with waveguide fabrication using femtosecond laser pulses 总被引:1,自引:0,他引:1
J.W. Chan T.R. Huser S.H. Risbud D.M. Krol 《Applied Physics A: Materials Science & Processing》2003,76(3):367-372
Atomic-scale structural changes have been observed in the glass network of fused silica after modification by tightly focused
800-nm, 130-fs laser pulses at fluences between 5 and 200 J cm-2. Raman spectroscopy of the modified glass shows an increase in the 490 and 605-cm-1 peaks, indicating an increase in the number of 4- and 3-membered ring structures in the silica network. These results provide
evidence that densification of the glass occurs after exposure to fs pulses. Fluorescence spectroscopy of the modified glass
shows a broad fluorescence band at 630 nm, indicating the formation of non-bridging oxygen hole centers (NBOHC) by fs pulses.
Waveguides that support the fundamental mode at 633 nm have been fabricated inside fused silica by scanning the glass along
the fs laser beam axis. The index changes are estimated to be approximately 0.07×10-3.
Received: 17 December 2001 / Accepted: 9 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +1-925/423-2463, E-mail: dmkrol@ucdavis.edu 相似文献
8.
Color center formation in soda lime glass and NaCl single crystals with femtosecond laser pulses 总被引:1,自引:0,他引:1
J.T. Dickinson S. Orlando S.M. Avanesyan S.C. Langford 《Applied Physics A: Materials Science & Processing》2004,79(4-6):859-864
The high instantaneous powers associated with femtosecond lasers can color many nominally transparent materials. Although the excitations responsible for this defect formation occur on subpicosecond time scales, subsequent interactions between the resulting electronic and lattice defects complicate the evolution of color center formation and decay. These interactions must be understood in order to account for the long term behavior of coloration. In this work, we probe the evolution of color centers produced by femtosecond laser radiation in soda lime glass and single crystal sodium chloride on different time scales, from microseconds to hundreds of seconds. By using an appropriately chosen probe laser focused through the femtosecond laser spot, we can follow the changes in coloration due to individual or multiple femtosecond pulses, and follow the evolution of that coloration for a long time after femtosecond laser radiation is terminated. For the soda lime glass, the decay of color centers is well described in terms of bimolecular annihilation reactions between electron and hole centers. Similar processes appear to operate in single crystal sodium chloride. PACS 82.50.Pt; 78.55.Qr; 78.55.Fv; 78.47.+p 相似文献
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10.
Spatially localized femtosecond pulses have been produced by a combination of scanning near-field optical microscopy with ultrashort pulse lasers. With these pulses direct ablative writing on metal surfaces is demonstrated. Possible applications of this technique for nanostructuring, repair, and production of lithographic masks are discussed. 相似文献
11.
V. S. Gorelik A. A. Ionin S. I. Kudryashov S. V. Makarov L. V. Seleznev D. V. Sinitsyn R. A. Chanieva A. R. Sharipov 《Bulletin of the Lebedev Physics Institute》2011,38(11):328-333
The prepared samples were characterized by reflection and transmission spectra of broadband visible-range radiation, and the
volume fraction of substances introduced into pores of artificial opals is estimated. It is found that the introduction of
solid-state nanoparticles with negative real part of the permittivity into opal pores results in a decrease in the effective
refractive index and a short-wavelength shift in the spectral position of the stop band in artificial opal. 相似文献
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实验通过二极管记录透射光信号随脉冲个数变化关系以及观测样品烧蚀形貌来研究不同实验条件对激光烧蚀的影响。使用的样品是厚度为50 m铝箔。实验中通过研究不同变量:激光焦点与样品的相对位置、激光的能量、背景气体压强以及脉冲形状对烧蚀加工过程和结果的影响,从而获得较好烧蚀效果的条件,达到控制烧蚀加工过程的目的。特别是通过使用不同形状的脉冲和具有一定规律的脉冲序列对样品进行烧蚀,发现某些形状的整形脉冲烧蚀结果明显优于变换极限脉冲。说明脉冲整形作为一种新的技术可以在激光精细钻孔领域得到更深入的研究和应用。 相似文献
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A. I. Grachev R. V. Romashko Yu. N. Kulchin S. S. Golik E. Nippolainen A. A. Kamshilin 《Laser Physics》2012,22(6):1064-1069
We demonstrate excitation of the linear photogalvanic current in a Bi12TiO20 crystal by two orthogonally polarized femtosecond laser pulses with detecting the electrical current via charge accumulation on the sample electrodes. Such a setup was used to implement an interferometric autocorrelation technique for characterization of ultrashort light pulses. Integration of the detected current in femtosecond time domain leads to vanishing of a bipolar component of the photogalvanic current which arises due to a pulse chirping. The advantage of the proposed technique is that it produces the electric field correlation function directly without the need for data processing using a compact, robust, and non-expensive detector in the form of a photoconductive cell of a non-centrosymmetric crystal. 相似文献
17.
S. Baudach J. Bonse W. Kautek 《Applied Physics A: Materials Science & Processing》1999,69(7):S395-S398
Some applications of polymer films require the microstructuring of partly uneven substrates. This cannot be achieved by conventional photolithography, usually performed with ultraviolet short-pulse lasers (excimer, fourth harmonic Nd:YAG). When processing thermally sensitive or undoped polymers with low optical absorption, the use of femtosecond laser pulses can improve the ablation precision, also reducing the heat-affected zone. Therefore, a Ti:sapphire laser system was employed to perform ablation experiments on polyimide (PI). The irradiated areas were evaluated by means of optical and scanning electron microscopy. Highly oriented ripple structures, which are related to the polarization state of the laser pulses, were observed in the cavities. The relationship between the ablation threshold fluence and the number of laser pulses applied to the same spot is described in accordance with an incubation model. 相似文献
18.
A three-dimensional reflectance scanning optical microscope based on the nonlinear optical phenomenon of second-harmonic generation is presented. A mode-locked Ti:sapphire laser producing <90-fs pulses at ~790nm was used, and the images were constructed by scanning of an object, which possessed local second-order nonlinearity, relative to a focused spot from the laser. The second-harmonic light at ~395nm generated by the specimen was separated from the fundamental beam by use of dichroic and interference filters and was detected by a photodiode. The technique was then used to characterize the distribution of second-order nonlinearity and microstructure of the nonlinear material lithium triborate. 相似文献
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采用脉宽为35~65 fs,中心波长为800 nm的飞秒脉冲激光对经抛光的镍片进行表面扫描处理,并在金属表面上制备了彩色镍图案;设置不同的激光扫描速度和能量密度扫描处理不锈钢表面,亦制备了彩色图案。介绍了实验过程,分析了实验结果,扫描电子显微镜(SEM)形貌分析显示,经过飞秒激光扫描处理的金属表面出现了纳米量级的激光诱导周期表面结构(NC-LIPSS),在镍上形成的结构周期约为480~510 nm,在不锈钢上形成的结构周期约为480~540 nm。 相似文献