Rapid fabrication of spiral phase plate on fused silica by laser-induced microplasma

Spiral phase plate is the most commonly used optical element for generating an optical vortex beam. It is widely applied due to its higher efficiency and less complex structure compared to other optical elements used for this purpose. The paper presents a simple, reliable and high-performance technology for manufacturing of a spiral phase plate on fused silica to generate an annular beam at a wavelength of 632.8 nm. The spiral phase plate is formed with the laser-induced microplasma processing method. In this case, the fabrication step takes no more than 7 min. We have performed and compared annealing in a furnace and chemical etching in an alkali solution as an additional treatment to significantly decrease surface roughness in the area of plasma plume action. Testing confirmed the working ability of the spiral phase plate according to the standard registering procedure of the ring intensity distribution in the far field.