Laser microplasma as a tool to fabricate phase grating applied for laser beam splitting

•Fabrication of having sinusoidal profile.•NIR laser radiation is used.•Main optical characteristics of formed gratings were investigated.•Phase grating used in the scheme of laser beam interference as a beam splitter.

In this paper, we present the method of phase gratings (PGs) formation on the fused silica by laser-induced black body heating (LIBBH) technology with irradiation of ytterbium fiber laser (λ=1.064 µm, τ ~ 4-200 ns, ν ~ 10-100 kHz). Formed PGs have sinusoidal profile with possible depth modulation of 0.5-2 µm. The PGs formation time, depending on its size and the period, ranged between 1 and 5 min. The optical characteristics of the PGs are studied and gained results are compared with the diffraction theory. This result shows that it is possible to fabricate different PGs with necessary optical characteristics by LIBBH technology. The potential application of such optical elements is beam splitting. Thus, the experiment with interference of laser beams has also been carried out in this work. The result of metal film processing by interference pattern is presented in the article.