Manufacturing method of spatially modulated waveplates

Method for manufacturing of spatially variant waveplates, including:

• focusing of linearly polarised ultrashort pulse laser radiation (USPLR) beam (2) with Gaussian intensity distribution in the material of a workpiece (5) that is transparent to USPLR beam (2),
• performing controlled displacement of the transparent material workpiece (5) with respect to a focused focal point of the USPLR beam (2) in accordance with the predetermined rule, while simultaneously changing a direction of USPLR polarization in the workpiece material, depending on the USPLR beam (2) focal point coordinates in the workpiece (5), wherein
• formation of nano-plates in spots of the workpiece (5) material affected by the focused USPLR beam (2) and their self-organization into periodic structures with a period shorter than USPLR wavelength take place, wherein the formed periodic structures are oriented perpendicularly to the USPLR polarization and covers a region in the workpiece material along the direction of the USPLR propagation, that is longer than the said wavelength of the USPLR more than 100 times,
• selecting of the focused USPLR beam focal area, a frequency of pulse repetition, energy thereof, and the workpiece (5) moving velocity so that the formed nano-plate structures (6) would position in the workpiece material space and function as birefringent optical elements with their characteristic phase delay, characterized in that a pulse duration of the USPLR pulses focused in the workpiece (5) material is from 500 fs to 2000 fs, their repetition period is from 1 μs to 50 μs, wherein
• a density of the focused USPLR pulse energy exceeds the threshold (10) determined by properties of the affected material only in the part of the focal area, the linearly polarized pulses of USPLR beam are delivered into the workpiece in sequences, wherein number of pulses in a sequence (16) is chosen to ensure the formation of the nano-plate structure (6) in the workpiece material.