Research of confocal 3D scanning method based on phase-only liquid crystal spatial light modulator

Confocal microscopy has been widely used in biomedicine, materials science, industrial testing and other areas for its unique optical sectioning property, high lateral resolution performance and nondestructive detection. Since confocal microscopy takes lateral detection point by point, which can only get the information at one spot a time, 3D scanning becomes necessary in the process of confocal measurement. The traditional methods of confocal scanning are mechanical means, of which the characteristics or mechanical driving technology limitations could not meet the requirements of live cell imaging and other application areas. Aiming at the shortcomings of mechanical scanning methods, the technology of controlling the three-dimensional position of focusing spot based on phase-only liquid crystal spatial light modulator (LCSLM) is researched, the confocal three-dimensional scanning system with no mechanical moving parts is designed, and the three-dimensional scanning of microscope objectives of focusing spot is realized. The main method is the modulation of the incident light on the phase and amplitude with liquid crystal spatial light modulator. The results prove that the scanning method can be achieved and the max-imum deflection angle is 0.021 rad, absolute error of beam deflection is |θ_error|<3.30×10^-8 rad≈1.89×10^-6, and the axial scanning range that can be realized is, [-55.6 mm, 55.6 mm].