TECHNOLOGY FOCUS - POLYMERS - Preferred Method: Each of the pores is formed via laser perforation of the slab or laser drilling of the slab, where a surface of the slab is coupled to a mask, and the mask is locally transparent to electromagnetic radiation emitted from a laser in a predefined manner that enables laser perforation of the slab through the areas of the mask that are transparent to the electromagnetic radiation. The method further comprises arranging the slab in proximity of a porous thin film, where the porous thin film is formed from a process that is different from the process used to form the porous slab. Preferred Components: The transmission of the laser light is measured according to ASTM D1003-00, procedure A, using D65 illumination, 10 degrees observer. The slab is formed from a polymer (P1) comprising at least one of polymethyl methacrylate, polystyrene, polyethylene, polypropylene, PTFE, polyvinylidene fluoride, polycarbonate, poly(4-methylpentene), cyclic olefin copolymers, polyamide, aromatic polyamide, poly(amide-imide), polyoxymethylene, polyphthalamide, polysulfone, polyethersulfone, polyphenylsulfone, liquid crystalline polymers, polyetherimide, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyphenylene oxide, polyimide, polyketone, polyetherketone, polyetheretherketone and/or polyphenylene sulfide, or their copolymer. The polymer (P1) comprises at least one of a UV absorbing additive comprising hydroxybenzophenones, hydroxybenzotriazoles, hydroxy benzotriazines, cyanoacrylates, oxanilides, benzoxazinones, benzylidene malonates, hindered amine light stabilizers and/or nanoscale inorganics. The slab: is formed from a material containing at least one a polymeric component or a component that absorbs electromagnetic radiation having wavelengths below 400 nm; has a total hole area of 10-80%; comprises many material layers; and is integrated as high temperature separator for lithium ion battery, a separator for an electrolytic supercapacitor, or a support membrane for a fuel cell membrane. The porous thin film: comprises the polymer (P1); and is based on polyethylene and melts at temperatures of 100-130 degrees C, thus providing a shutdown mechanism, where the porous thin film has a thickness of at least 5 mu .