Structures for a polarizer and methods of forming a structure for a polarizer. A first slotted waveguide component is positioned over a first waveguide core, and a second slotted waveguide component positioned over the first slotted waveguide component. The first slotted waveguide component includes a second waveguide core and a third waveguide core separated by a first slot, and the second slotted waveguide component includes a fourth waveguide core and a fifth waveguide core separated by a second slot. The first waveguide core is laterally aligned with the first slot and the second slot.