1064-nm, nanosecond laser mirror thin film damage competition

Negres, Raluca A.; Stolz, Christopher J.; Thomas, Michael; Caputo, Mark

doi:10.1117/12.2324022

Cited by 5 publications

(2 citation statements)

References 8 publications

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“…Apart from the pulse duration, it has been found that the coating deposition method also plays a key role in the optical performance of the coatings. For instance, the coatings deposited by electron beam evaporation produce relatively porous films and contain low internal stress [21]. Therefore, these coatings were found to be highly resistant for high-energy nanosecond laser applications.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond Laser-Induced Damage Characterization of Multilayer Dielectric Coatings

Velpula¹,

Kramer²,

Rus³

2020

Coatings

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The laser-induced damage threshold (LIDT) of optical components is one of the major constraints in developing high-power ultrafast laser systems. Multi-layer dielectric (MLD) coatings-based optical components are key parts of high-power laser systems because of their high damage resistance. Therefore, understanding and characterizing the laser-induced damage of MLD coatings are of paramount importance for developing ultrahigh-intensity laser systems. In this article, we overview the possible femtosecond laser damage mechanisms through damage morphologies in various MLD optical coatings tested in our facility. To evaluate the major contributions to the coating failure, different LIDT test methods (R-on-1, ISO S-on-1 and Raster Scan) were carried out for a high reflective hybrid Ta2O5/HfO2/SiO2 MLD mirror coating at a pulse duration of 37 fs. Different LIDT test methods were compared due to the fact that each test method exposes the different underlying damage mechanisms. For instance, the ISO S-on-1 test at a higher number of laser pulses can bring out the fatigue effects, whereas the Raster Scan method can reveal the non-uniform defect clusters in the optical coating. The measured LIDT values on the sample surface for the tested coating in three test methods are 1.1 J/cm2 (R-on-1), 0.9 J/cm2 (100k-on-1) and 0.6 J/cm2 (Raster Scan) at an angle of incidence of 45 deg. The presented results reveal that the performance of the tested sample is limited by coating defects rather than fatigue effects. Hence, the Raster Scan method is found to be most accurate for the tested coating in evaluating the damage threshold for practical applications. Importantly, this study demonstrates that the testing of different LIDT test protocols is necessary in femtosecond regime to assess the key mechanisms to the coating failure.

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Section: Introductionmentioning

confidence: 99%

Femtosecond Laser-Induced Damage Characterization of Multilayer Dielectric Coatings

Velpula¹,

Kramer²,

Rus³

2020

Coatings

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show abstract

“…In general, metal oxides (SiO 2 , Al 2 O 3 , HfO 2 , Ta 2 O 5 , Nb 2 O 5 , and TiO 2 ) and metal fluorides (MgF 2 and Na 3 AlF 6 ) are common layer materials applied for coating design in the visible and near-infrared spectral range. Conventional electron-beam evaporation (EBE) remains the preferred vacuum coating technology for nanosecond pulsed laser devices [1,2]. Plasma ion-assisted deposition (PIAD) and magnetron sputtering (MS) have been successfully employed for femtosecond laser systems [3,4].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Ultralow Stress TiO2/SiO2 Optical Coatings by Plasma Ion-Assisted Deposition

Guo

Kong

2020

Coatings

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Optical and mechanical properties of multilayer coatings depend on the selected layer materials and the deposition technology; therefore, knowledge of the performances of thin films is essential. In the present work, titanium dioxide (TiO2) and silicon dioxide (SiO2) thin films have been prepared by plasma ion-assisted deposition (PIAD). The optical, structural, and mechanical properties of thin films have been investigated using spectrometer/ellipsometer, X-ray diffraction (XRD), atomic force microscopy (AFM), and laser interferometer. The results show that TiO2 film fabricated by PIAD induces a high refractive index, wide optical band gap, amorphous structure, smooth surface, and tensile stress. In the case of SiO2 film, high bias voltage leads to dense structure and compressive stress. As an application, a three-wavelength high reflectance at 632.8, 808, and 1550 nm was optimized and deposited. The dependence of total stress in the multilayer on the substrate temperature was studied as well. In conclusion, it was demonstrated that PIAD is an effective method for the preparation of ultralow stress TiO2/SiO2 multilayer films. The achieved stress was as low as 1.4 MPa. The result could provide guidance to the stress optimization of most optical components without prefiguring, backside coating, and postdeposition treatments.

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Study of short-wavelength pass dichroic laser mirror coatings with hafnia–silica mixture layers

Sun,

Zhao,

Zhu

et al. 2024

Optics & Laser Technology

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1064-nm, nanosecond laser mirror thin film damage competition

Cited by 5 publications

References 8 publications

Femtosecond Laser-Induced Damage Characterization of Multilayer Dielectric Coatings

Femtosecond Laser-Induced Damage Characterization of Multilayer Dielectric Coatings

Fabrication of Ultralow Stress TiO2/SiO2 Optical Coatings by Plasma Ion-Assisted Deposition

Study of short-wavelength pass dichroic laser mirror coatings with hafnia–silica mixture layers

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