Laser damage growth with picosecond pulses

Sozet, Martin; Néauport, Jérôme; Lavastre, Éric; Roquin, Nadja; Gallais, Laurent; Lamaignère, Laurent

doi:10.1364/ol.41.002342

Cited by 31 publications

(12 citation statements)

References 20 publications

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“…We have investigated the growth behavior of laser damage sites on HR mirrors at the wavelength of 1.030µm in the sub-picosecond pulse duration regime. We confirm that damage areas evolve linearly with the number of shots as follow 0 n S n S α = × + as shown in [14]. The growth coefficient α is proportional to the fluence and is modified by the polarization of the incoming beam.…”

Section: Resultssupporting

confidence: 79%

“…This linear growth evolves as 0 n S n S α = × + , where 0 S and n S are the initial damage area and the damage area after n laser pulses, respectively. α is the linear growth coefficient, increasing with the fluence set during growth sequence [14]. In this work, we investigate more deeply the growth behavior in the sub-picosecond regime in an attempt to identify the physical phenomena in place during growth.…”

Section: Introductionmentioning

confidence: 99%

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Sub-picosecond laser damage growth on high reflective coatings for high power applications

et al. 2017

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Growth of laser damage on High Reflection (HR) thin film coatings is investigated at the wavelength of 1.030µm in the sub-picosecond regime. An experimental laser damage setup in a pump / probe configuration is used to study the growth behavior of engineered damage sites as well as laser damage sites. Results demonstrate that engineered sites and laser damage sites grow identically which indicates that the growth phenomenon is intrinsic to materials and stack design. In order to analyze the experimental results, we have developed a numerical model to simulate growth. Using FEM simulations, we demonstrate that growth is governed by the evolution of the electric field distribution in the mirror stack under the successive laser shots, which is supported by time-resolved observations of damage growth events. Eventually the results are compared to laser damage observations made on of full scale PETAL mirrors, which fully support the approach.

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Section: Resultssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Sub-picosecond laser damage growth on high reflective coatings for high power applications

et al. 2017

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“…According to the ISO standard, 20 it corresponds to the energy density at the top of the Gaussian transverse beam intensity profile, and we calculate it as the ratio of the total energy in the beam to the effective beam area (set as the area at 1∕e for a Gaussian beam). 21 In all cases in Fig. 8, the transition of the damage probability from 1 to 0 is very sharp, indicating that the damage is primarily intrinsic, governed by the coating materials' electronic properties rather than by structural or nanoscale defects in the coating.…”

Section: Lidt Tests Of the Bbhr Coating Of Run 072mentioning

confidence: 83%

“…For ps and sub-ps pulses, coating defects play a role in nonpropagating damage behavior to a lesser extent or not at all, 21,25 and propagating damage primarily results from intrinsic damage mechanisms based on direct interaction of the laser radiation with the coating layer materials. Figure 12 shows the 800-and 8-ps pulse NIF-MEL LIDT results in the form of a plot of cumulative number of nonpropagating damage sites versus fluence, with arrows indicating the fluences at which propagating damage occurs.…”

Section: Lidt Tests Of the Bbhr Coating Of Run 071mentioning

confidence: 99%

Analysis of laser damage tests on coatings designed for broad bandwidth high reflection of femtosecond pulses

et al. 2016

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Abstract. We designed an optical coating based on TiO 2 ∕SiO 2 layer pairs for broad bandwidth high reflection (BBHR) at 45-deg angle of incidence (AOI), P polarization of femtosecond (fs) laser pulses of 900-nm center wavelength, and produced the coatings in Sandia's large optics coater by reactive, ion-assisted e-beam evaporation. This paper reports on laser-induced damage threshold (LIDT) tests of these coatings. The broad HR bands of BBHR coatings pose challenges to LIDT tests. An ideal test would be in a vacuum environment appropriate to a high energy, fs-pulse, petawatt-class laser, with pulses identical to its fs pulses. Short of this would be tests over portions of the HR band using nanosecond or sub-picosecond pulses produced by tunable lasers. Such tests could, e.g., sample 10-nm-wide wavelength intervals with center wavelengths tunable over the broad HR band. Alternatively, the coating's HR band could be adjusted by means of wavelength shifts due to changing the AOI of the LIDT tests or due to the coating absorbing moisture under ambient conditions. We had LIDT tests performed on the BBHR coatings at selected AOIs to gain insight into their laser damage properties and analyze how the results of the different LIDT tests compare.

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“…The density of growing damage sites is in fact the main parameter that must be evaluated to qualify an Continued on next page 10.1117/2.1201607.006548 Page 2/3 optical component. 5 The bandgap of the material ultimately limits the damage threshold (and bandgap and refractive index are interrelated). Thus, there is also a clear correlation between the refractive index and the LIDT 6 (see Figure 2).…”

Section: Laurent Gallaismentioning

confidence: 99%