Concave microlens arrays produced by femtosecond laser with HF acid etching

The concave microlens arrays were fabricated on K9 optical glasses using the technology of femtosecond laser and hydrofluoric acid etching on the surface of optical glass. This concave MLA as mold can achieve lots of convex MLAs by replication. The surface micromorphology and optical diffraction characteristics of the concave microlens array were analyzed respectively by the phase contrast electronic microscope and the scanning electron microscope. The process was parameter-controllable and implemented simply. Those concave microlens arrays can be applied to the field of light splitting, beam smoothing and parallel photolithography etc.