Machining of sub-micron holes using a femtosecond laser at 800 nm

Pronko, P. P.; Dutta, S. K.; Squier, Jeffrey A.; Rudd, J. V.; Du, D.; Mourou, G.

doi:10.1016/0030-4018(94)00585-i

Cited by 456 publications

(227 citation statements)

References 4 publications

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“…The depth of such holes (0.5 m in diameter) was measured to be 50 nm with atomic force microscopy. Similar results have been observed by others (9,12,29). This depth is on the order of 30 nm, the skin depth corresponding to ionization of all Ϸ10 23 ͞cm 3 valence electrons, and we conclude that all valence electrons are ionized at breakdown.…”

Section: The Depth Of Features Indicates That Damage Occurs When All supporting

confidence: 92%

“…1a). This effect allows fabrication of submicrometer features (7)(8)(9)(10)(11)), and we demonstrate that even nanoscale features can be produced with ultrahigh precision (Fig. 1 b- For pulses longer than Ϸ10 ps, the threshold fluence for optically induced dielectric breakdown depends strongly on the pulse duration and scales with T 1/2 , where T is the pulse duration (e.g., ref.…”

Section: Laser-matter Interaction At Critical Intensitymentioning

confidence: 63%

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Optics at critical intensity: Applications to nanomorphing

Joglekar

Liu

Meyhöfer

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

251

173

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Laser-induced optical breakdown by femtosecond pulses is extraordinarily precise when the energy is near threshold. Despite numerous applications, the basis for this deterministic nature has not been determined. We present experiments that shed light on the basic mechanisms of light-matter interactions in this regime, which we term ''optics at critical intensity.'' We find that the remarkably sharp threshold for laser-induced material damage enables the structure or properties of materials to be modified with nanometer precision. Through detailed study of the minimum ablation size and the effects of polarization, we propose a fundamental framework for describing light-matter interactions in this regime. In surprising contrast to accepted damage theory, multiphoton ionization does not play a significant role. Our results also reject the use of the Keldysh parameter in predicting the role of multiphoton effects. We find that the dominant mechanism is Zener ionization followed by a combination of Zener and Zenerseeded avalanche ionization. We predict that the minimum feature size ultimately depends on the valence electron density, which is sufficiently high and uniform, to confer deterministic behavior on the damage threshold even at the nanoscale. This behavior enables nanomachining with high precision, which we demonstrate by machining highly reproducible nanometer-sized holes and grooves in dielectrics.

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Section: The Depth Of Features Indicates That Damage Occurs When All supporting

confidence: 92%

Section: Laser-matter Interaction At Critical Intensitymentioning

confidence: 63%

Optics at critical intensity: Applications to nanomorphing

Joglekar

Liu

Meyhöfer

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

251

173

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“…Femtosecond micromachining of metals began in the early nineties; holes were drilled into metals, such as nickel, copper, silver and gold [27,[31][32][33]. Microcolumns on silicon, which were already known to be produced by long pulsed lasers (such as nanosecond lasers), were also fabricated by fs laser machining in 1995 [28].…”

Section: Brief History Of Surface Structuring With Femtosecond Lasersmentioning

confidence: 99%

Fabrication of Micro/Nano Structures on Metals by Femtosecond Laser Micromachining

2014

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Abstract:Femtosecond laser micromachining has emerged in recent years as a new technique for micro/nano structure fabrication because of its applicability to virtually all kinds of materials in an easy one-step process that is scalable. In the past, much research on femtosecond laser micromachining was carried out to understand the complex ablation mechanism, whereas recent works are mostly concerned with the fabrication of surface structures because of their numerous possible applications. The state-of-the-art knowledge on the fabrication of these structures on metals with direct femtosecond laser micromachining is reviewed in this article. The effect of various parameters, such as fluence, number of pulses, laser beam polarization, wavelength, incident angle, scan velocity, number of scans, and environment, on the formation of different structures is discussed in detail wherever possible. Furthermore, a guideline for surface structures optimization is provided. The authors' experimental work on laser-inscribed regular pattern fabrication is presented to give a complete picture of micromachining processes. Finally, possible applications of laser-machined surface structures in different fields are briefly reviewed.

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“…The cooling rates can be even higher, in excess of 10 13 K/s [9], when the laser energy deposition is confined not only within the thin surface layer of the irradiated target but also in the lateral dimensions, creating conditions for even faster two-or three-dimensional heat transfer from the absorption region. The laterally localized laser energy deposition can be achieved by using tightly focused laser beams [10][11] or taking advantage of the local field enhancement in the vicinity of a tip of a scanning probe microscope [12,13]. Since the number of highly non-equilibrium interrelated processes above can be involved into the material response to a short laser pulse irradiation and since those processes can take place on a wide spatial and time scales, it can be difficult, or sometimes impossible, to treat the obtained experimental data with a definite confidence.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale structures generation within the surface layer of metals with short UV laser pulses

Сергеевич¹,

Andreas²,

Барбель³

et al. 2017

Naučno-teh. vestn. inf. tehnol. meh. opt.

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Article in EnglishFor citation: Ivanov D.S., Blumenstein A., Rethfeld B., Veiko V.P., Yakovlev E.B., Garcia M.E., Simon P., Ihlemann J. Nanoscale structures generation within the surface layer of metals with short UV laser pulses. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2017, vol. 17, no. 1, pp. 1-15. doi: 10.17586/2226-1494-2017 Abstract We have completed modeling of a laser pulse influence on a gold target. We have applied a hybrid atomistic-continuum model to analyze the physical mechanisms responsible for the process of nanostructuring. The model combines the advantages of Molecular Dynamics and Two Temperature Model. We have carried out a direct comparison of the modeling results and experimental data on nano-modification due to a single ps laser pulse at the energy densities significantly exceeding the melting threshold. The experimental data is obtained due to a laser pulse irradiation at the wavelength of 248 nm and duration of 1.6 ps. The mask projection (diffraction grating) creates the sinusoidal intensity distribution on a gold surface with periods of 270 nm, 350 nm, and 500 nm. The experimental data and modeling results have demonstrated a good match subject to complex interrelations between a fast material response to the laser excitation, generation of crystal defects, phase transitions and hydrodynamic motion of matter under condition of strong laser-induced non-equilibrium. The performed work confirms the proposed approach as a powerful tool for revealing the physical mechanisms underlying the process of nanostructuring of metal surfaces. Detailed understanding of the dynamics of these processes gives the possibility for designing the topology of functional surfaces on nano-and micro-scales. Keywords UV laser pulses, nanostructuring, simulations, molecular dynamics Acknowledgements The reported study was supported partially by the Ministry of Education and Science of Russia, research agreement No.14.578.21.0197 (RFMEFI57816X0197, by RFBR grant No. 14-29-07227 OFI-M, and the Government of the Russian Federation Grant No. 074-U01, and DFG grants IV 122/1-1, IV 122/1-2, and IH 17/18-1. Аннотация Выполнено моделирование воздействия лазерного импульса на золотую мишень. С этой целью применена гибридная модель, сочетающая молекулярную динамику и анализ на основе непрерывной (континуальной) двухтемпературной модели, способная проанализировать механизмы, ответственные за процесс наноструктурирования. Проведено прямое сравнение данных моделирования и экспериментальных результатов по наномодификации поверхности одним лазерным импульсом пикосекундной длительности при плотностях энергии, значительно превышающих порог плавления. Экспериментальные результаты получены при воздействии лазерного излучения с длиной волны 248 нм и длительностью импульса 1,6 пс. Проекция маски (дифракционной решетки) на поверхность золота создает распределение интенсивности синусоидальной формы с периодом 500 нм. Продемонстрировано хорошее совпадение экспериментальных данных с результата...

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Machining of sub-micron holes using a femtosecond laser at 800 nm

Cited by 456 publications

References 4 publications

Optics at critical intensity: Applications to nanomorphing

Optics at critical intensity: Applications to nanomorphing

Fabrication of Micro/Nano Structures on Metals by Femtosecond Laser Micromachining

Nanoscale structures generation within the surface layer of metals with short UV laser pulses

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