Micromachining bulk glass by use of femtosecond laser pulses with nanojoule energy

Schaffer, Chris B.; Brodeur, A.; Garcı́a, J.F.; Mazur, Eric

doi:10.1364/ol.26.000093

Cited by 713 publications

(329 citation statements)

References 15 publications

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“…Thereby, the use of the femtosecond laser has already become an essential technology in micromachining [3][4][5][6]. Nevertheless, the laser drilling of glass is still imperfect, mainly because precision processing is impaired by the irregular microscopic damage that occurs during drilling [7].…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of damage formation in glass in the process of femtosecond laser drilling

et al. 2018

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The development of femtosecond lasers has renovated micromachining technology, enabling the microdrilling of transparent materials at high speed. Although effective, this technique is still imperfect because irregular microscopic damage occurs during processing. Several factors in the formation of damage induced by a single laser pulse have been suggested; however, the entire mechanisms of damage formation in the process of drilling are not fully understood. Here we investigated the causes of microscopic damage both by experimentally carrying out laser drilling on chemically strengthened glass samples and by numerically analyzing the propagating stress wave and temperature distribution. We have revealed that the damage at the sidewall and bottom of a generated hole is mainly due to the stress wave, while the damage around the hole entrance is mainly due to relaxation of thermal stress. In particular, we have analyzed these processes quantitatively, demonstrating the time courses of the passage of the stress wave through the material and the temperature distribution generated by the excited electrons. Our analyses are useful in suggesting processing techniques, or suggesting glass materials suitable for laser drilling such as glass with high heat resistance, which may lead to an improvement in the quality of micromachining.

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Section: Introductionmentioning

confidence: 99%

Mechanisms of damage formation in glass in the process of femtosecond laser drilling

et al. 2018

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“…With the industrial need for precise modification of optical materials growing rapidly, the ultrashort laser pulse interaction with these materials is gaining increased attention [1][2][3][4][5][6][7][8][9][10][11][12]. It has been shown that the use of ultrashort laser pulses allows for a variety of modifications to highly localized regions both on the surface and in the bulk of transparent materials [13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Interaction of ultrashort-laser pulses with induced undercritical plasmas in fused silica

et al. 2012

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R. 2012. Interaction of ultrashort-laser pulses with induced undercritical plasmas in fused silica. Phys Rev A, 85(1):013808.PHYSICAL REVIEW A 85, 013808 (2012) Interaction of ultrashort-laser pulses with induced undercritical plasmas in fused silica Ultrafast light-material interactions near the damage threshold are often studied using postmortem analysis of damaged dielectric materials. Corresponding simulations of ultrashort pulse propagation through the material are frequently used to gain additional insight into the processes leading to such damage. However, comparison between such experimental and numerical results is often qualitative, and pulses near to but not exceeding the damage threshold leave no permanent changes in the material for postmortem analysis. In this article, a series of experiments is presented that measures the near-and far-field properties of a 140-fs laser pulse after propagation through a fused silica sample in which a noncritical electron plasma was generated. Concurrently, results from simulations in which the laser pulse was numerically constructed according to the nearfield beam profile and frequency resolved optical gating (FROG) trace are presented. It is found that to extract a quantitative comparison of such data, cylindrical symmetry of the laser pulse in simulations should be abandoned in favor of a fully 3 + 1D Cartesian representation. Further comparison of experimental and calculated damage thresholds shows that time-corrective effects predicted by the Drude model play a critical role in the physics of both pulse evolution and plasma formation. The influence of resulting spatiotemporal dependences of the pulse in far-field measurements leads to unretrievable FROG traces. However, it is shown through both simulation and experiment that the use of an appropriate beam aperture will eliminate this effect when measuring the temporal pulse amplitude.

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“…So far, pressures in excess of 0.1 TPa have been obtained using a diamond anvil in stationary conditions, while transient pressures behind shock waves generated by chemical or nuclear explosions or generated using powerful lasers up to 50 TPa have been reported [1,2]. Here we present experimental evidence that one can create TPa pressures, many times the strength of any material, using low energy pulses from a conventional tabletop laser.Recent studies have demonstrated [3][4][5][6][7][8] that sub-ps laser pulses tightly focused inside transparent dielectrics (glasses, crystals, and polymers) can produce detectable sub-micrometer-sized structural modifications, including voids. This requires intensities in excess of 10 14 W=cm 2 which results in a highly nonlinear light-matter interaction with most dielectrics being ionized early in the laser pulse.…”

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confidence: 99%

Laser-Induced Microexplosion Confined in the Bulk of a Sapphire Crystal: Evidence of Multimegabar Pressures

et al. 2006

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Extremely high pressures ( 10 TPa) and temperatures (5 10 5 K) have been produced using a single laser pulse (100 nJ, 800 nm, 200 fs) focused inside a sapphire crystal. The laser pulse creates an intensity over 10 14 W=cm 2 converting material within the absorbing volume of 0:2 m 3 into plasma in a few fs. A pressure of 10 TPa, far exceeding the strength of any material, is created generating strong shock and rarefaction waves. This results in the formation of a nanovoid surrounded by a shell of shock-affected material inside undamaged crystal. Analysis of the size of the void and the shock-affected zone versus the deposited energy shows that the experimental results can be understood on the basis of conservation laws and be modeled by plasma hydrodynamics. Matter subjected to record heating and cooling rates of 10 18 K=s can, thus, be studied in a well-controlled laboratory environment. DOI: 10.1103/PhysRevLett.96.166101 PACS numbers: 81.07.ÿb, 47.40.Nm, 62.50.+p, 81.40.ÿz The study of matter in conditions of extreme pressure and temperature is an exciting area of condensed matter physics relevant to the formation of new materials and modeling the state of matter inside stars and planets. Creation of such extreme conditions in the laboratory is, however, a formidable experimental task. So far, pressures in excess of 0.1 TPa have been obtained using a diamond anvil in stationary conditions, while transient pressures behind shock waves generated by chemical or nuclear explosions or generated using powerful lasers up to 50 TPa have been reported [1,2]. Here we present experimental evidence that one can create TPa pressures, many times the strength of any material, using low energy pulses from a conventional tabletop laser.Recent studies have demonstrated [3][4][5][6][7][8] that sub-ps laser pulses tightly focused inside transparent dielectrics (glasses, crystals, and polymers) can produce detectable sub-micrometer-sized structural modifications, including voids. This requires intensities in excess of 10 14 W=cm 2 which results in a highly nonlinear light-matter interaction with most dielectrics being ionized early in the laser pulse. To achieve such high intensities the laser beam should be tightly focused using high numerical aperture optics into a spot whose dimensions are of the order of the laser wavelength ( ).Previously the formation of voids in silica was associated with self-focusing of the laser beam [3]. In fact void formation can occur in conditions favorable for selffocusing if the beam is weakly focused into the sample [9]. Previously, however, there has been no systematic study of void formation by single fs pulses in conditions when self-focusing cannot occur. We demonstrate here that in such conditions nanovoids are formed by the extreme temperatures and pressures created by optical breakdown and these drive shock and rarefaction waves in the surrounding material. It is possible that new materials [10 -12] with altered chemical properties [13] could be formed by such micro-explosions.The inte...

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Micromachining bulk glass by use of femtosecond laser pulses with nanojoule energy

Cited by 713 publications

References 15 publications

Mechanisms of damage formation in glass in the process of femtosecond laser drilling

Mechanisms of damage formation in glass in the process of femtosecond laser drilling

Interaction of ultrashort-laser pulses with induced undercritical plasmas in fused silica

Laser-Induced Microexplosion Confined in the Bulk of a Sapphire Crystal: Evidence of Multimegabar Pressures

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