To bypass this unresolved problem, many calculations of femtosecond laser ablation of nonmetals have been based on free electron density distribution without the actual consideration of the phase change mechanism. May 22, 2015 in the aim of performing pumpprobe experiments with a high temporal accuracy, the determination of the perfect temporal overlap of the two incoming pulses is crucial. Introduction femtosecond laser induced breakdown in transparent materials has attracted much attention in recent years. In particular, many media are transparent at low or moderate optical intensities, but become strongly absorbing once the threshold for laserinduced breakdown is. The physical mechanisms and ensuing material modification associated with laserinduced damage in multilayer dielectric high reflectors is.
Recently, a new laser micromachining technique using multiple femtosecond pulses with a picosecondtonanosecond separation as a train group has demonstrated the ability to increase the ablation quality of dielectrics and semiconductors. Laser induced damage of dielectrics down to few cycle pulse. Femtosecond laserinduced refractive index changes at the. Nanosecondto femtosecond laserinduced breakdown in dielectrics. In order to more exactly predict femtosecond pulse laser induced damage threshold, an accurate theoretical model taking into account photoionization, avalanche ionization and decay of electrons is proposed by comparing respectively several combined ionization models with the published experimental measurements. Measurement of femtosecond laserinduced damage and. This paper reports the physical phenomenon of the temporal overlapping double femtosecond laser induced ablation enhancement at different time delays. The target surface is illuminated with incoherent grazing red light stocker yale specbright led spotlight centered at 630 nm, so that the imaging system is the equivalent of an in situ dark. The formation of laserinduced periodic surface structures lipss in different materials metals, semiconductors, and dielectrics upon irradiation with linearly polarized fslaser pulses. Therefore, we investigate the laser resistance of different dielectrics of. A theoretical model is constructed to explain the femtosecond laserinduced damage initiation mechanism on the mmdg, and the model can simulate the evolution of the electron density in the conduction band and the change of the dielectric constants of hfo 2 and sio 2 in the sandwiched grating structure. Femtosecond laser induced damage of pulse compression. In this paper, we report on the characterization of electronbeamdeposited dielectrics, namely, al 2 o 3, y 2 o 3, sc 2 o 3, hfo 2, ta 2 o 5, tio 2, and sio 2.
We report extensive laserinduced damage threshold measurements on dielectric materials at wavelengths of 1053 and 526 nm for pulse durations tau ranging from 140 fs to 1 ns. Box 808, l493, livermore, ca 94550 abstract we report extensive laserinduced damage threshold measurements on pure and multilayer. Chemical stoichiometric geass glasses were prepared, and their thermal properties, refractive index n, optical bandgap, raman gain, and femtosecond laser damage were examined. This article deals with the recent advances in photochemistry in optical materials induced by femtosecond laser pulses. Calculation of femtosecond pulse laser induced damage. High temporal resolution and calibration in pumpprobe. We calculate the transient freeelectron density in laserirradiated dielectrics with two different approaches, both considering the energy distribution of excited electrons. Femtosecond laserinduced damage threshold of electron beam deposited dielectrics for 1m class optics adrien hervy, a,b,c laurent gallais, b, gilles cheriaux, c and daniel mouricaud a. The damage in dielectrics under femtosecond laser irradiation can be explained by formation of selftrapped electrons, coulomb explosion and melting or evaporating. The grating ridge of this type of mmdg consists of a layer of hfo 2 sandwiched between two sio 2 layers. Imaging system with one objective obj1 inside the vacuum chamber, and a second objective obj2 outside of the chamber, imaging the target on a ccd camera with magni.
Although the damage is mdest in lattice changes, the coupling with the laser pulse occurs through electrons. Pdf femtosecond laser induced coulomb explosion from. The time it takes to switch on and off electric current determines the rate at which signals can be processed and sampled in modern information technology 1,2,3,4. Femtosecond selfrecon guration of laserinduced plasma patterns in dielectrics jeanluc d eziel,1 louis j. Here, we present an experimental approach to overcome this.
Osa enhancement of femtosecond laserinduced surface. We defined surface damage as a sudden change in surface damage morphology, i. Jan 14, 2009 read measurement of femtosecond laser induced damage and ablation thresholds in dielectrics, applied physics a. Using micrometer scale manual stages, the specimen is able to translate about. For nanosecond and longer pulses, however, nondeterministic damage is often observed, where the probability of damage increases smoothly around the threshold. Related content femtosecond laser ablation dynamics of dielectrics.
This role can be both negative a factor which limits laser intensity in highpower laser systems or material under study and positive providing a tool for material processing and modification. Femtosecond laserinduced damage threshold in snow micro. Numerous studies have investigated the role of photoionization in ultrafast laser induced damage of bulk dielectrics. Laser induced damage of aucoated gratings acg and metal multilayer dielectric gratings mmdg for pulse compression were measured using 800 35 nm femtolaser with pulse width of 30. Measurement of femtosecond laserinduced damage and ablation thresholds in dielectrics fig. We report on extensive femtosecond laser damage threshold measurements of. Femtosecond laserinduced damage threshold of electron beam. Laser induced damage damage produced by pulsed lasers in transparent dielectrics begins with the conversion of electromagnetic energy into kinetic energy of electrons. Laserinduced damage in sio 2 and caf 2 with picosecond and femtosecond laser pulses. Osa raman gain and femtosecond laser induced damage of ge. When addressing laserdielectrics interaction, this time zero is often estimated from the dynamics of interest itself e.
We present the tests results of the intrinsic materials and the evolution of the laser induced damage threshold lidt with the increase of the number of pulses for different materials. It was also developed a formalism that explains the damage processes. We show that different damage characterization techniques and data treatment procedures from a single experiment provide complementary physical results characterizing lasermatter interaction. Pdf laserinduced damage in dielectrics with nanosecond to. We report extensive laser induced damage threshold measurements on pure and multilayer dielectrics at 1053 and 526 nm for pulse durations, 2, ranging from 140 fs to 1 ns. Analysis of damage thresholds of laser scanning mirrors using. Femtosecond laser induced density changes in geo2 and sio2.
A theoretical model is constructed to explain the femtosecond laser induced damage initiation mechanism on the mmdg, and the model can simulate the evolution of the electron density in the conduction band and the change of the dielectric constants of hfo 2 and sio 2 in the sandwiched grating structure. Jun 10, 2015 an experimental and numerical study of the laser induced damage of the surface of optical material in the femtosecond regime is presented. Pdf we report extensive laserinduced damage threshold measurements on dielectric materials at wavelengths of 1053 and 526 nm for pulse durations tau. We report extensive laser induced damage threshold measurements on dielectric materials at wavelengths of 1053 and 526 nm for. Femtosecond laserinduced periodic surface structures.
Our proposal was employed on glass gratings to show the effectiveness of the method and its potential to design transmission gratings with enhanced laser induced damage threshold. Laserinduced damage lid in optical materials plays a significant role in lasermatter interaction phenomena. Theoretical considerations have been done to assess the impact of contributing ionization phenomena in order to find a valid description for laserinduced damage in the femtosecond fs domain. Laser induced damage of dielectrics down to few cycle. The kinetic approach solves a system of complete boltzmann collision integrals describing different excitation and relaxation processes in detail. Some effects affecting laserinduced damage of solid. Femtosecond laserinduced damage threshold of electron beam deposited dielectrics for 1m class optics. Laserinduced damage in sio2 and caf2 with picosecond and femtosecond laser pulses. The temperature dependence of the laserinduced damage threshold on optical coatings was studied in detail for laser pulses from 123 k to 473 k at different temperature. Laserinduced breakdown and damage in bulk transparent materials induced by tightly focused femtosecond laser pulses to cite this article. The initial damage position is on the hfo 2 layer of the. Subsequently, a special set of sample has been designed to verify these considerations via iso certified laser damage testing.
Pdf measurement of femtosecond laserinduced damage and. Detailed thermodynamic modeling demonstrates the ablation enhancement is highly dependent on the first pulses laser fluence. Frequency dependence in the initiation of ultrafast laser. Materials science processing on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. This paper reports the physical phenomenon of the temporal overlapping double femtosecond laserinduced ablation enhancement at different time delays. To produce damage, energy deposited with electrons must be. Sa crystals in single shot mode in the femtosecond regime down to few optical cycles damage in dielectrics with nanosecond to subpicosecond pulses l experimental b.
Nonablative mechanism of femtosecond laser drilling of bulk dielectrics is proposed which is assuming concentrating and condensation of lasergenerated vacancies into a void in a center of a laser waist at presence of picosecond photo. Femtosecond laserinduced damage threshold of electron beam deposited dielectrics for 1m class optics adrien hervy, a,b, c laurent gallais, b, gilles cheriaux, c and daniel mouricaud a. Sem, the laser induced surface damage morphologies and ablation of the crystalline silicon wafers were analyzed. Read measurement of femtosecond laserinduced damage and ablation thresholds in dielectrics, applied physics a. We report extensive laserinduced damage threshold measurements on dielectric materials at. Femtosecond laser damage and ablation of dielectrics. The paper is focused on the importance of accurate determination of surface damage ablation threshold of a dielectric material irradiated with femtosecond laser pulses. Perry laserinduced damage in dielectrics with nanosecond to subpicosecond pulses ii. Femtosecond laser induced surface swelling in polymethyl methacrylate farhana baset, konstantin popov, ana villafranca, jeanmichel guay, zeinab alrekabi, andrew e.
Femtosecond laserinduced damage of dielectrics request pdf. It remains a big challenge to theoretically predict the material removals mechanism in femtosecond laser ablation. Dec 19, 2016 ultrashort pulse laser ablation of dielectrics. Band gap energy and refractive index dependence of. Laserinduced damage in sio2 and caf2 with picosecond and femtosecond. Dynamics of femtosecond laserinduced breakdown in water from. In addition, we examine the respective role of ionization and avalanche ionization in femtosecond laser induced damage. Femtosecond laserinduced damage threshold in snow microstructured targets 3 figure 2. The objective of this work is to investigate the different. Interaction of dielectrics with femtosecond laser pulses.
Pdf femtosecond laserinduced damage threshold of electron. Reliability of laser safety eye wear in the femtosecond regime. We measure the laserinduced damage threshold lidt fluence under single shot at the surface of sapphire samples prepared following the standards of two methods yielding to different surface. Femtosecond laserinduced damage threshold of electron beam deposited dielectrics for 1m class optics article pdf available in optical engineering 561.
The formation mechanisms of laserinduced color centers, nanoclusters, nanoparticles and. This temperature dependence was reversed for pulses shorter than a. Multiphoton absorption mechanism is assumed to provide main contribution to the femtosecond damage behavior of dielectric thin films. A novel, compact model for the calculation of ultrafast laser induced damage threshold in terms of the thin film refractive index and band gap energy is achieved in the present research.
Mechanisms of femtosecond laserinduced breakdown and. For example, one may have quite deterministic laser induced damage for femtosecond pulses, which reliably sets in when the damage threshold is reached. Fundamental mechanisms of laserinduced damage in optical. This study examines the role of spectral width and instantaneous laser frequency in laser induced damage using a frequency dependent multiphoton ionization model and numerical simulation of an 800 nm laser pulse propagating through fused silica. Femtosecond laser induced damage characterization of. We report on an experimental study of the laserdamage resistance and other optical properties of coating materials deposited in a 1m class coating chamber. Femtosecondlaserinduced damage initiation mechanism on. Midinfrared femtosecond laserinduced damages in as 2 s 3. Laserinduced damage in dielectrics with nanosecond to. Pdf nanosecondtofemtosecond laserinduced breakdown in. F c, where f c is the laserinduced breakdown fluence. Femtosecond pulse s on 1 lidt in dielectric materials.
In order to transport multipetawatt pw femtosecond laser beams with large spectral bandwidth, specific mirrors have to be designed and manufactured. We present the tests results of the intrinsic materials and the evolution of the laserinduced damage threshold lidt with the increase of the number of pulses for different materials. Lutherdavies1 1research school of physical science and engineering, australian national university, canberra, act 0200 australia 2p. Measurement of femtosecond laserinduced damage and ablation thresholds in dielectrics a high magni. Femtosecond laser processing of crystalline silicon. There have been many studies of femtosecond laserinduced breakdown and damage in transparent dielectrics and applications in micromachining. Pdf the paper is focused on the importance of accurate determination of surface damageablation threshold of a dielectric material irradiated with. Qualitative differences in the morphology of damage and a departure from the diffusiondominated 2112. Mechanisms of picosecond laserinduced damage in common. A series of microthermocouples, deposited onto the surface, was used to measure heatings at the millisecond scale, at typically 50. Osa calculations and experimental demonstration of multi. Since the invention of lasers in early 60s, material ablation with various laser sources has been one of the most demanded technologies for drilling micronanoholes in various materials, cutting, formation of trenches and other surface and volume relief structures, and material funtionalization 1,2,3,4,5.
Qualitative differences in the morphology of damage and a departure from the diffusiondominated. Extending our previous work on the dynamics of femtosecond laser ablation from dielectrics, we concentrate in this contribution on calcium fluoride 111 surfaces. We report extensive laserinduced damage threshold measurements on dielectric materials at wavelengths of 1053 and 526 nm for pulse durations. The 1st order diffraction efficiency of the acg is over 90% in wavelength range from 700 to nm. Messaddeq,2 youn es messaddeq,2 and charles varin1,3,4. Laser induced damage in multilayer dielectric gratings due. Results of laser induced damage threshold lidt of fused silica, sapphire and ti. Pdf laserinduced damage in dielectrics with nanosecond. Nanosecondto femtosecond laser induced breakdown in dielectrics. Femtosecond laser induced density changes in geo 2 and sio 2 glasses. Optilayer thin film software manual, optilayer gmbh 2015. A modified rate equation is used to numerically calculate damage in dielectrics.
Femtosecond laserinduced damage in dielectrics core. Femtosecond laserinduced damage threshold of electron. The formation of laserinduced periodic surface structures lipss in different materials metals, semiconductors, and dielectrics upon irradiation with linearly polarized fslaser pulses s 30150 fs, k 800 nm in air environment is studied experimentally and theoretically. Femtosecond laserinduced refractive index changes at the surface of dielectrics. The field of investigation of this paper is limited to bulk solid isotropic transparent materials glasses and polymers, specifically tailored with photoactive agents. Rp photonics encyclopedia laserinduced damage, optical. When addressing laser dielectrics interaction, this time zero is often estimated from the dynamics of interest itself e.
We find that present results are in quantitative agreement with those of earlier study. Laserinduced damage has been studied since the early days of the laser 12, but damage caused by femtosecond laser pulses is fundamentally different from damage caused by laser pulses with a. Femtosecond selfrecon guration of laser induced plasma patterns in dielectrics jeanluc d eziel,1 louis j. Importance of surface topography on pulsed laserinduced. Robust optimization of the laser induced damage threshold of. Femtosecond selfrecon guration of laserinduced plasma. Laserinduced damage threshold measurements were performed on homogeneous and multilayer dielectrics and goldcoated optics at 1053 and 526 nm for pulse durations. Femtosecond laser induced surface swelling in polymethyl. Optical damage in nonmetals dielectrics may severely affect the performance of highpower laser systems as well as the efficiency of optical systems based on.
Read femtosecond laser damage and ablation of dielectrics. Measuring thermal effects in femtosecond laserinduced. Optical damage in nonmetals dielectrics may severely affect the performance of highpower laser systems as well as the efficiency of optical systems based on nonlinear processes and has therefore been subject to extensive research for some 30 years. Jan 14, 2009 the paper is focused on the importance of accurate determination of surface damageablation threshold of a dielectric material irradiated with femtosecond laser pulses. For pulses longer than a few picoseconds, the laserinduced damage threshold of coated substrates increased with decreasing temperature. A series of laser induced damage threshold experiments are carried out at various wavelengths. Jul 30, 2002 a quartz sample was submitted to femtosecond laser pulses with fluences up to 6. Materials removals during femtosecond laser nonthermal. The femtosecondlaserinduced damage behaviors of metal multilayer dielectric gratings mmdg for pulse compression are explored. Measurement of femtosecond laserinduced damage and ablation. Nonlinear absorption of tightlyfocused femtosecond laser pulses inside transparent materials creates a hightemperature plasma at the laser focus, providing. For instance, commercial picosecond and femtosecond laser systems can reach pulse. Laserinduced damage in dielectrics with nanosecond to subpicosecond pulses. Laser induced breakdown and damage in bulk transparent materials induced by tightly focused femtosecond laser pulses to cite this article.
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