Dual wavelength laser-induced damage threshold measurements of alumina/silica and hafnia/silica ultraviolet antireflective coatings

Mrohs, Marius; Jensen, Lars; Günster, Stefan; Alig, Thimotheus; Ristau, Detlev

doi:10.1364/ao.55.000104

Cited by 13 publications

(3 citation statements)

References 14 publications

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“…Laser-induced periodic surface structure (LIPSS) formation on metals [17,18], semiconductors [19] and dielectrics [20,21] has been intensively investigated by the two-colour (UV-IR) double-pulse femtosecond laser irradiation. The two-colour double-pulse irradiation has been used for laser-induced damage threshold (LIDT) testing of optical coatings [22][23][24][25], and has proved to reduce the damage threshold by 71% for Al 2 O 3 coating [26]. Better control in the energy deposition has been demonstrated during dual-wavelength double-pulse laser machining of dielectrics [27].…”

Section: Introductionmentioning

confidence: 99%

The behaviour of sapphire under intense two-colour excitation by picosecond laser

Gedvilas¹,

Stankevič²,

Račiukaitis³

2021

physics

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Ultrashort pulse lasers are evidencing their benefits in the processing of transparent materials. Sapphire is one of the most attractive engineering materials today. It is hard and, therefore, difficult to machine mechanically to the required shape. Laser dicing is one of the promising techniques for sapphire separation. Two-pulse two-colour irradiation was applied to initiate free-shape cutting of the material. Two collinear laser beams with wavelengths of 1064 and 355 nm, pulse duration of 10 ps and inter-pulse delay of 0.1 ns were combined to induce intra-volume modifications (directional cracks) in sapphire for wafer separation. The photon energy of both beams is well below the band gap, and various channels of the multi-photon excitation were involved in the process. Significant enhancement in the modification area was experimentally observed when intensities of focused infrared and ultraviolet beams were within narrow ranges. We discuss the resonant laser–sapphire interaction mechanisms, leading to up to four times higher excitation of the material involving multiple photons and energetic levels of intrinsic defects in the band-gap. The energy level schemes of colour centres involved in two-step multi-photon absorption in sapphire under intensive laser irradiation have been prepared.

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Section: Introductionmentioning

confidence: 99%

The behaviour of sapphire under intense two-colour excitation by picosecond laser

Gedvilas¹,

Stankevič²,

Račiukaitis³

2021

physics

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“…The laser-induced periodic surface structure (LIPSS) or ripple formation by the two-colour (UV-IR) double pulse femtosecond laser irradiation on conductors 20, 21 semiconductors 22 and dielectrics 23 has been intensively investigated 24 . The two-colour double-pulse irradiation has been used for laser induced damage thresholds (LIDT) of coatings 25–28 and has proved to reduce the damage threshold by 71% for Al 2 O 3 coating 29 . It has been demonstrated that dual-wavelength double pulse laser machining is an efficient way to improve the laser processing of dielectrics by providing a better control of the energy deposition process 30 .…”

Section: Introductionmentioning

confidence: 99%

Multi-photon absorption enhancement by dual-wavelength double-pulse laser irradiation for efficient dicing of sapphire wafers

Gedvilas

Mikšys

Berzinš

et al. 2017

Sci Rep

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The evidence of multi-photon absorption enhancement by the dual-wavelength double-pulse laser irradiation in transparent sapphire was demonstrated experimentally and explained theoretically for the first time. Two collinearly combined laser beams with the wavelengths of 1064 nm and 355 nm, inter-pulse delay of 0.1 ns, and pulse duration of 10 ps were used to induce intra-volume modifications in sapphire. The theoretical prediction of using a particular orientation angle of 15 degrees of the half-wave plate for the most efficient absorption of laser irradiation is in good agreement with the experimental data. The new innovative effect of multi-photon absorption enhancement by dual-wavelength double-pulse irradiation allowed utilisation of the laser energy up to four times more efficiently for initiation of internal modifications in sapphire. The new absorption enhancement effect has been used for efficient intra-volume dicing and singulation of transparent sapphire wafers. The dicing speed of 150 mm/s was achieved for the 430 μm thick sapphire wafer by using the laser power of 6.8 W at the repetition rate of 100 kHz. This method opens new opportunities for the manufacturers of the GaN-based light-emitting diodes by fast and precise separation of sapphire substrates.

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“…In modern laser systems, optical surfaces may be operated at different wavelengths simultaneously. Recent studies [52,53] imply a significant reduction of the damage thresholds at the individual wavelengths for such operation conditions. Consequently, the power handling capability of a specific component will be overestimated, if the threshold values for single wavelength operation are presumed for the design of laser systems.…”

mentioning

confidence: 99%

Standardization in Optics Characterization

Ristau¹

International Trends in Applied Optics

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An adapted quality management is a major prerequisite for the reliable production of optical components and coatings. Especially laser applications impose highest demands on modern optical systems and can be considered as a major pacemaker for the development of advanced quality management strategies. Therefore, most of the standardized concepts for the determination of the properties necessary for a comprehensive quality control, as for example losses and transfer functions as well as laser-induced damage thresholds or defect densities of optical surfaces, are based on laser systems. This contribution is intended to offer a brief review on the present status of optics characterization and the related standards often applied in the production of laser components. A selection of International Standards will be presented with focus on the determination of laser induced damage thresholds (ISO 21254), optical absorption (ISO 11551), and Total Scattering (ISO 13696). The corresponding measurement methods will be described and discussed before the background of recent developments in laser technology. Finally, some aspects of the future development and projects of international standardization activities will be discussed.

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Dual wavelength laser-induced damage threshold measurements of alumina/silica and hafnia/silica ultraviolet antireflective coatings

Cited by 13 publications

References 14 publications

The behaviour of sapphire under intense two-colour excitation by picosecond laser

The behaviour of sapphire under intense two-colour excitation by picosecond laser

Multi-photon absorption enhancement by dual-wavelength double-pulse laser irradiation for efficient dicing of sapphire wafers

Standardization in Optics Characterization

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