Didelės energijos keturių lėkių Nd:YAG stiprintuvas su SBS impulso spūda interferenciniam struktūravimui /

Surface structuring allows for the creation of specific structures on the surface or volume of a material. The technique is widely used in electronics [1], biomedicine [2] and materials science [3]. Due to its versatility, high speed, precision and simplicity, lasers are often used in surface structuring. Direct Laser Interference Patterning (DLIP), is a laser-based technology that uses the physical principle of interference of high-intensity coherent laser beams, as well as laser ablation, to create functional periodic microstructures. Evident periodic microstructures can be produced in a very short time, with spacing ranging from sub-micrometres to 20 mm [5]. The structures produced can be of various types: lines, crosses, dots, depending on the number and positioning of the laser beams. Ceramics [6], metals [7] and polymers [6] can all be processed with this technique. This approach is also used for micromachining of biofunctional synthetic surfaces, biosensors and tissue engineering [8]. One of the applications of the periodic structures obtained by this technique is to impart hydrophobic properties to the surface being modified. Surface wettability modifications have potential applications in many different fields, such as self-cleaning materials [9], corrosion mitigation [10], and water resistance improvement. Picosecond laser pulses are the most relevant for material surface structuring due to their simplicity and versatility: 100 ps order laser pulses have enough intensity to create multi-photon absorption, and they do not induce plasmoid interactions, which makes the patterning much easier to control. The interaction of multiple coherent light beams can produce a variety of periodic structures whose shape and period depend on the number and arrangement of the beams. In a four-pass Nd:YAG amplifier configuration, we observed ~20 mJ energy at ~75 times gain. Although, laser beam of a minimum 3.91 mm diameter is required to achieve ~45 mJ maximum energy in order to prevent laser induced damage from optical elements. Using SBS-PCM, we could realize picosecond pulses from 1.05 nanosecond seed pulses, with average pulse duration of ~110 ps, and standard deviation of 5.4% and a range of only 28.3 picoseconds, which is fully sufficient for laser ablation in direct laser interference patterning. By increasing the beam to 4.2 mm, the wavefront distortion could be corrected using SBS-PCM, but more measurements are needed to find the optimal beam size, as the corrected beam shrunk to 3.2 mm. We were also able to compensate wavefront distortions caused by the amplification process and laser beam propagation through the optical elements, which allows us to obtain a higher-quality output beam [13] suitable for direct laser interference patterning. After splitting the output beam into two parts, we captured the interference lines with different periods. Comparison of the interference images obtained with nanosecond and SBS-compressed picosecond pulses showed no difference. By rotating the polarization of the linearly polarized fibers forming the interference lines, we can control the intensity distribution of the interference pattern.

Grantor dc:publisher

Institutional Repository of Vilnius University

Year dc:date

2024

Author dc:creator

• Klumbys, Domantas,

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

lit

Repository record dc:identifier

https://repository.vu.lt/VU:ELABAETD210580107&prefLang=en_US

OAI identifier oai:identifier

oai:vu.lt:elaba:210580107