Modeling and characterization of wavefront morphologies of laser induced damages on dielectric coating

Zheng, Yi; Liu, Zhichao; Luo, Jin; Pan, Feng; Wang, Jian; Xu, Qiao

doi:10.1016/j.optcom.2017.07.030

Cited by 3 publications

(4 citation statements)

References 17 publications

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“…Equation (12) shows that the highest intensification is generated by structures for which all the elements interfere constructively. It corresponds to the case of a pure phase object (transmittances equal to 1), which cannot generate higher intensifications than (1 + 2m) 2 . This limit is very large and, in most cases, it will not be reached.…”

Section: Field Decomposition In Light-blocking Disksmentioning

confidence: 99%

“…Applying Eq. (13) to a structure with phase differences of π leads to the intensification limit I str ≤ (1 + 2m) 2 . This result can be interpreted with the Fresnel zones [29].…”

Section: Field Decomposition In Light-blocking Disksmentioning

confidence: 99%

“…Generally, defects in optical components feature much more complex shapes than the light-blocking disk considered in Arago's seminal experiment [2]. In this paper, we extend the concept of opaque disk diffraction by considering multiple disks that model defects with complex morphology.…”

Section: Introductionmentioning

confidence: 99%

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Strong Light Intensifications Yielded by Arbitrary Defects: Fresnel Diffraction Theory Applied to a Set of Opaque Disks

et al. 2019

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Two centuries ago, Fresnel, Poisson, and Arago showed how the wave nature of light induces a bright spot behind an opaque disk. We develop an analytical model based on the Fresnel diffraction theory to show how small perturbations such as digs or scratches can yield intense light enhancements on the downstream axis. The impact of defects with complex morphology on light diffraction is shown to be accurately modeled by the Fresnel theory applied to a set of opaque disks characterized by phase shift and transmittance. This model can be used either to define the geometry of the defects that optimizes the light enhancement or to improve the defect specification on the surface of the optical components. We explain why partial information of the defect morphology can suffice to specify a safety distance beyond which light intensifications are not dangerous. The validity of this analytical approach is studied by measuring the intensifications created by three different microdefects.

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Section: Field Decomposition In Light-blocking Disksmentioning

confidence: 99%

“…Applying Eq. (13) to a structure with phase differences of π leads to the intensification limit I str ≤ (1 + 2m) 2 . This result can be interpreted with the Fresnel zones [29].…”

Section: Field Decomposition In Light-blocking Disksmentioning

confidence: 99%

See 1 more Smart Citation

Strong Light Intensifications Yielded by Arbitrary Defects: Fresnel Diffraction Theory Applied to a Set of Opaque Disks

et al. 2019

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“…Based on Fresnel diffraction theory, Tournemenne et al [19] developed an analytical model to show how small perturbations, such as digs or scratches, can yield intense light enhancements on the downstream axis. Zheng et al [20] also discovered that a special configuration of the laser damaged coating causes wave-front modulation, which affects the downstream light field propagation. However, there are few studies on how surface mitigated contours on KDP crystals affect downstream light field propagation.…”

Section: Introductionmentioning

confidence: 99%

Application of light diffraction theory to qualify the downstream light field modulation property of mitigated KDP crystals

Yang

Cheng

Liu

et al. 2021

Optics & Laser Technology

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Characterization of surface defects using a phase retrieval technique in a high-power laser system

et al. 2022

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In the framework of high-power lasers, surface defects on optics can generate strong light intensification and induce damage sites on downstream optics. To evaluate this intensification during high-energy laser shots, a three-step method is proposed. First, a dedicated measurement bench is designed to measure the intensification induced by defects on a wide variety of optics, including amplifier slabs, KDP crystals, mirrors, gratings, and vacuum windows, for propagation distances up to 2000 mm. A multi-resolution single-beam multiple-intensity reconstruction phase retrieval algorithm is then used to reconstruct a model of the defect, in both amplitude and phase, from a set of intensification measurements. Finally, the impact of the modeled defect on downstream optics is evaluated with a simulation of the high-power laser system. This method is experimentally validated through a case study of damage identified on one of the Laser Mégajoule (LMJ) beams, characterized with the method presented in this paper. The long-distance impact on the LMJ beam is estimated by simulation and compared to a direct near-field measurement.

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Modeling and characterization of wavefront morphologies of laser induced damages on dielectric coating

Cited by 3 publications

References 17 publications

Strong Light Intensifications Yielded by Arbitrary Defects: Fresnel Diffraction Theory Applied to a Set of Opaque Disks

Strong Light Intensifications Yielded by Arbitrary Defects: Fresnel Diffraction Theory Applied to a Set of Opaque Disks

Application of light diffraction theory to qualify the downstream light field modulation property of mitigated KDP crystals

Characterization of surface defects using a phase retrieval technique in a high-power laser system

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