A preparation method of a liquid-free
zoom terahertz lens based on a superoleophobic-lipophilic surface, comprising the following steps: First step, select a
solid substrate with a high terahertz
transmittance, and etch induced microstructures on the
substrate surface; Second step, after the etched substrate is cleaned with
alcohol, it is immersed in a fluorosilane solution and then taken out and dried to carry out
chemical modification to reduce the surface free energy of the
solid substrate and construct the chemical components required for a superoleophobic surface; Third step, set a region where the
liquid lens is to be formed, and perform a
laser scan again on this set region with low power parameters to form a "lipophilic-superoleophobic" patterned
hybrid surface; Fourth step, inject oil droplets into the lipophilic region of the "lipophilic-superoleophobic" surface, and under the action of
surface tension, form a liquid terahertz lens with a uniform surface curvature. In the present invention, by slowly increasing or decreasing the liquid, the spherical curvature of the lens can be continuously changed, and stepless adjustment of the
focal length can be achieved.