Fig. 4: Experimental results on focusing.

a Focusing assessment system. b Beam spot patterns acquired at various distances when a laser with a wavelength of 632.8 nm is incident on a single-layer Pancharatnam-Berry lens for a designed wavelength of 632.8 nm and a focal length of 320 mm. c Beam profile patterns at the designed focal position for incident beams with wavelengths of 1064, 632.8, and 532.8 nm after passing through a three-layer cascade liquid crystal Pancharatnam-Berry lens (CLCPBL). d Photographs of multiple focal points generated by 632 nm light at different positions after passing through a three-layer CLCPBL. e Photograph of focused spot at the focal point with 532 nm light. f Photograph depicting the variation in focal intensity of a 405 nm laser incident on the CLCPBL as the voltage is modulated.