Laser processing of sapphire and fabrication of diffractive optical elements

Gottumukkala, Narayana Raju; Gupta, Mool C.

doi:10.1364/ao.452810

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…Microrelief diffraction optical elements (DOEs) are formed on sapphire substrates, designed to function at high radiation powers and temperatures [4][5][6]. To create the microrelief diffraction optical elements on the surface of sapphire substrates, both photolithography methods [4] and the method of laser ablation with femtosecond pulses of ultraviolet radiation are used [5,6]. The micro-profiled sapphire substrates are also proposed to be used to create media for long-term data storage.…”

Section: Analysis Of the State Of The Problemmentioning

confidence: 99%

Formation of submicron relief structures on the surface of sapphire substrates

Petrov

Kryuchyn

Gorbov

et al. 2023

Phys. Chem. Solid St.

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An analysis of technologies that allow creating microrelief structures on the surface of sapphire substrates has been carried out. It is shown that the most effective method of forming relief structures with submicron dimensions is ion beam etching through a protective mask formed by photolithography. The main problems in creating a microrelief on the surface of sapphire substrates are the removal of static electric charge in the process of ion beam etching of the substrates, as well as obtaining a protective mask with windows of specified sizes, through which etching of the sapphire substrate is performed.

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Section: Analysis Of the State Of The Problemmentioning

confidence: 99%

Formation of submicron relief structures on the surface of sapphire substrates

Petrov

Kryuchyn

Gorbov

et al. 2023

Phys. Chem. Solid St.

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“…To improve the quality of laser-processed surfaces, ablation could be combined with additional processes such as laser-induced plasma-assisted ablation [ 8 , 9 ] or laser-induced backside wet etching [ 10 , 11 , 12 ]. By using ablation in combination with additional thermal processing [ 13 ] or direct laser writing in combination with chemical post-processing, optical components such as lenses [ 14 , 15 ] or diffractive optical elements [ 16 , 17 , 18 ] could be made. Nevertheless, these technologies are limited to the microprocessing and achievement of 2D geometries, and most cannot produce arbitrary-shaped 3D structures.…”

Section: Introductionmentioning

confidence: 99%

Sapphire Selective Laser Etching Dependence on Radiation Wavelength and Etchant

et al. 2022

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Transparent and high-hardness materials have become the object of wide interest due to their optical and mechanical properties; most notably, concerning technical glasses and crystals. A notable example is sapphire—one of the most rigid materials having impressive mechanical stability, high melting point and a wide transparency window reaching into the UV range, together with impressive laser-induced damage thresholds. Nonetheless, using this material for 3D micro-fabrication is not straightforward due to its brittle nature. On the microscale, selective laser etching (SLE) technology is an appropriate approach for such media. Therefore, we present our research on C-cut crystalline sapphire microprocessing by using femtosecond radiation-induced SLE. Here, we demonstrate a comparison between different wavelength radiation (1030 nm, 515 nm, 343 nm) usage for material modification and various etchants (hydrofluoric acid, sodium hydroxide, potassium hydroxide and sulphuric and phosphoric acid mixture) comparison. Due to the inability to etch crystalline sapphire, regular SLE etchants, such as hydrofluoric acid or potassium hydroxide, have limited adoption in sapphire selective laser etching. Meanwhile, a 78% sulphuric and 22% phosphoric acid mixture at 270 °C temperature is a good alternative for this process. We present the changes in the material after the separate processing steps. After comparing different processing protocols, the perspective is demonstrated for sapphire structure formation.

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“…Because of their ultrashort pulse widths and ultrahigh peak power, femtosecond lasers are suitable for processing almost any material, especially hard and brittle materials [8][9][10][11]. Femtosecond laser processing has many advantages, such as a small heat-affected zone, high precision and high efficiency [12,13].…”

Section: Introductionmentioning

confidence: 99%

Prediction Model for Liquid-Assisted Femtosecond Laser Micro Milling of Quartz without Taper

Yuan

Chen

et al. 2022

Micromachines

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The strong nonlinear absorption effect and “cold” processing characteristics of femtosecond lasers make them uniquely advantageous and promising for the micro- and nanoprocessing of hard and brittle materials, such as quartz. Traditional methods for studying the effects of femtosecond laser parameters on the quality of the processed structure mainly use univariate analysis methods, which require large mounts of experiments to predict and achieve the desired experimental results. The method of design of experiments (DOE) provides a way to predict desirable experimental results through smaller experimental scales, shorter experimental periods and lower experimental costs. In this study, a DOE program was designed to investigate the effects of a serious of parameters (laser repetition frequency, pulse energy, scan speed, scan distance, scan mode, scan times and laser focus position) on the depth and roughness (Ra) of the fabricated structure through the liquid-assisted femtosecond laser processing of quartz. A prediction model between the response variables and the main parameters was defined and validated. Finally, several blind holes with a size of 50 ×50m2 and a depth of 200m were fabricated by the prediction model, which demonstrated the good consistency of the prediction model.

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Laser processing of sapphire and fabrication of diffractive optical elements

Cited by 5 publications

References 28 publications

Formation of submicron relief structures on the surface of sapphire substrates

Formation of submicron relief structures on the surface of sapphire substrates

Sapphire Selective Laser Etching Dependence on Radiation Wavelength and Etchant

Prediction Model for Liquid-Assisted Femtosecond Laser Micro Milling of Quartz without Taper

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