共查询到20条相似文献,搜索用时 15 毫秒
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通过使用波长 800nm、重复频率 250kHz的飞秒激光脉冲聚焦进Li2O-Nb2O5-SiO2组分的玻璃内部,空间选择性诱导出铌酸锂微晶.为了进一步地研究辐照区域晶体的生长机制,使用显微拉曼光谱仪分析了玻璃样品辐照区域不同位置的结构变化.研究表明,在飞秒激光辐照一段时间后的聚焦区域,由于非线性效应和热累积效应形成了一个高温辐射梯度场,在激光辐照中心区域超过玻璃的析晶温度而促使玻璃熔融析晶. 相似文献
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Internal modification of transparent materials such as glass can be carried out using multiphoton absorption induced by a femtosecond (fs) laser. The fs‐laser modification followed by thermal treatment and successive chemical wet etching in a hydrofluoric (HF) acid solution forms three‐dimensional (3D) hollow microstructures embedded in photosensitive glass. This technique is a powerful method for directly fabricating 3D microfluidic structures inside a photosensitive glass microchip. We used fabricated microchips, referred to as a nanoaquarium, for dynamic observations of living microorganisms. In addition, the present technique can also be used to form microoptical components such as micromirrors and microlenses inside the photosensitive glass, since the fabricated structures have optically flat surfaces. The integration of microfluidics and microoptical components in a single glass chip yields biophotonic microchips, in other words, optofluidics, which provide high sensitivity in absorption and fluorescence measurements of small volumes of liquid samples. 相似文献
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The effect of spherical aberration on temperature distribution inside glass by irradiation of a high repetition rate femtosecond pulse laser 下载免费PDF全文
In this paper, we study the effect of spherical aberrations on the light intensity and the temperature distribution in the focal region in a 250-kHz femtosecond laser irradiated Ag+-doped borosilicate glass. When a focused beam goes through an interface between air and glass, spherical aberration will result in the separation of the focal point and then cause a clear change of the light intensity distribution along the incident direction. That phenomenon will further influence the longitudinal cross-section temperature distribution in glass. Here we use Ag nanoparticle formation as a marker for establishing temperature distribution and we find that the formation of nanoparticle shows a strong dependence on the temperature field and the detailed precipitation process is also discussed. 相似文献
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Study of the microstructural transformations of borate glass and barium metaborate crystals induced by femtosecond laser 下载免费PDF全文
This paper describes the microstructural transformations of borate glass and barium metaborate crystals induced by femtosecond laser. Such structural transformations were verified by Raman spectroscopy. The borate glass is transformed into low temperature (LT) phase of barium metaborate (BaB_2O_4) crystals after being irradiated for 10 min by a femtosecond laser. In addition, after 20 min of irradiation, high temperature (HT) phase of BaB_2O_4 crystals is also produced. Further studies demonstrate that LT phase BaB_2O_4 crystals are formed in the HT phase BaB_2O_4 crystals after femtosecond laser irradiation for 10 s. 相似文献
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将800nm高重复频率250 kHz的飞秒激光分别聚焦到掺Ag和没有掺Ag的Gd2O3-MoO3- B2O3玻璃表面,研究掺Ag对飞秒激光诱导析晶的影响。对激光辐照的区域显微拉曼分析发现对于没掺Ag玻璃,诱导玻璃析晶需要的激光功率和辐照时间比掺了Ag的玻璃要大要长,这说明Ag的掺入促进了玻璃的析晶。其机理可能为飞秒激光的多光子吸收效应,导致玻璃基质中桥氧键断裂,产生非桥氧空穴和自由电子,玻璃中的Ag离子捕获电离出来的电子被还原成Ag原子,Ag原子在热动力的驱动下移动聚集形成银纳米颗粒,形成的银纳米团簇作为核促进了钼酸盐玻璃的析晶。 相似文献
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Douglas J. Little Martin Ams Simon Gross Peter Dekker Christopher T. Miese Alex Fuerbach Michael J. Withford 《Journal of Raman spectroscopy : JRS》2011,42(4):715-718
A general picture of refractive index change mechanisms in glass modified by a femtosecond laser has proven elusive. In this paper, Raman microscopy was used in conjunction with refractive near‐field profilometry to analyse the structure of borosilicate glass (Schott BK7) modified by a femtosecond laser and determine the mechanism of the observed refractive index change. For a pulse repetition rate of 1 kHz, it was determined that the refractive index change was due to an elevated population of non‐bridging oxygen atoms, resulting in more ionic bonds forming within the glass network and increasing the molar refractivity of the glass. For a pulse repetition rate of 5.1 MHz, the dominant mechanism of refractive index change was densification and rarefaction of the glass network. Different refractive index change mechanisms were attributed to different thermal conditions imparted to the glass under different pulse repetition rates. Implications for device fabrication are also discussed. These findings constitute an important step toward a complete overview of femtosecond‐laser‐induced refractive index change in glass. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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The physical process of forming a modified region in soda-lime glass was investigated using 1 kHz intense femtosecond laser pulses from a Ti: sapphire laser at 775 nm. Through the modifications induced by the femtosecond laser radiation using selective chemical etching techniques, we fabricated reproducible and defined microstructures and further studied their morphologies and etching properties. Moreover, a possible physical mechanism for the femtosecond laser modification in soda-lime glass was proposed. 相似文献
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Y. Dai J. Qiu X. Hu L. Yang X. Jiang C. Zhu B. Yu 《Applied physics. B, Lasers and optics》2006,84(3):501-505
We investigated the effect of cerium oxide on the precipitation of Ag nanoparticles in silicate glass via a femtosecond laser irradiation and successive annealing. Absorption spectra show that Ce3+ ions may absorb part of the laser energy via multiphoton absorption and release free electrons, resulting in an increase of the concentration of Ag atoms and a decrease of the concentration of hole-trapped color centers, which influence precipitation of the Ag nanoparticles. In addition, we found that the formed Ag0 may reduce Ce4+ ions to Ce3+ ions during the annealing process, which inhibits the growth of the Ag nanoparticles. PACS 78.55.Qr; 78.67.Bf; 81.05.Pj 相似文献
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对中心波长为800 nm,脉宽为100 fs的激光脉冲烧蚀空气中硅(111)产生的等离子体发射光谱进行了时间和空间分辨研究. 结果表明,在等离子体羽膨胀初期(小于50 ns时间范围内),等离子体发射光谱主要由连续光谱构成,此后连续光谱强度逐渐减弱,线状光谱开始占主导地位;在羽体膨胀过程中离子谱线的存在时间短于原子谱线的存在时间. 由时间分辨发射光谱发现在羽体膨胀过程中等离子体辐射波长存在红移现象,波长红移量随时间演化呈二次指数衰减. 最后给出等离子体发射光谱谱线强度的时空演化规律.
关键词:
飞秒激光
脉冲激光烧蚀
等离子体
发射光谱 相似文献
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Zhanfeng Tu Yu Teng Jiajia Zhou Shifeng Zhou Heping Zeng Jianrong Qiu 《Journal of Raman spectroscopy : JRS》2013,44(2):307-311
Localized microstructure and elemental redistribution were induced in bismuth germanate glasses by irradiation with high repetition rate 800 nm femtosecond laser pulses. The confocal Raman spectra were examined to study the redistribution of elements and residual thermal stress. The microscopic Raman spectra indicated that the residual thermal stress increases from the unmodified region to the center of the laser modified region, while Bi is enriched at the boundary area of the inner structure of the laser modified region relative to Ge. Electron microprobe analysis further confirmed the elemental redistribution of Bi and Ge, which agrees well with the Raman spectral analysis. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Fabrication of large-scale ripples on fluorine-doped tin oxide films by femtosecond laser irradiation 下载免费PDF全文
The large-scale uniform self-organized ripples are fabricated on fluorine-doped tin oxide (FTO) coated glass by femtosecond laser. They can be smoothly linked in a horizontal line with the moving of XYZ stage by setting its velocity and the repetition rate of the laser. The ripple-to-ripple linking can also be realized through line-by-line scanning on a vertical level. The mechanism analysis shows that the seeding effect plays a key role in the linking of ripples. 相似文献
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We report on space-selective co-precipitation of silver and gold nanoparticles in Ag+, Au3+ co-doped silicate glasses by irradiation of femtosecond laser pulses and subsequent annealing at high temperatures. The color of the irradiated area in the glass sample changed from yellow to red with the increase of the annealing temperature. The effects of average laser power and annealing temperature on precipitation of the nanoparticles were investigated. A reasonable mechanism was proposed to explain the observed phenomena. 相似文献
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利用波长为800 nm的飞秒激光,在空气和去离子水中诱导钛表面形成不同的周期条纹结构。在空气中,激光能量密度为0.265 J/cm2时,钛表面主要形成周期为500~560 nm低空间频率条纹结构;激光能量密度为0.102 J/cm2时,主要形成的是周期为220~340 nm高空间频率条纹结构。两种条纹均垂直于入射激光偏振方向,且条纹周期随着脉冲重叠数的增大而增大。在水中,除形成垂直激光偏振方向、周期为215~250 nm的高空间频率条纹结构,还形成了平行于激光偏振方向且周期约为入射激光波长八分之一的高空间频率条纹结构。利用表面等离子体理论、二次谐波及Sipe理论对各种周期条纹结构的形成机理进行分析,发现周期条纹结构的形成与钛表面氧化层有密切的关系。 相似文献
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飞秒激光能够在极短时间内烧蚀炸药产生高温高压等离子体。可以利用飞秒激光对含能材料或含能元器件进行精密加工。深入认识飞秒激光烧蚀炸药过程中,炸药内部的热效应是发展飞秒激光加工炸药技术的基础。建立了单脉冲飞秒激光烧蚀炸药过程的流固耦合计算模型,考虑了在高温高压等离子体和炸药自热反应的共同作用下,炸药内部的热效应。对飞秒激光烧蚀TNT炸药过程进行了流体力学数值模拟。计算结果表明:TNT炸药中未烧蚀区域产生了热效应,峰值温度高于TNT炸药的点火温度,但由于炸药内热效应区域极小,高温持续时间极短,因此炸药内温度迅速下降,没有发生点火现象。 相似文献