2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/165942Based on the transformation media theory, the authors propose a way to replace a wide window with a narrow slit filled with designed metamaterial to achieve the same transmittance as the one of the window. Numerical simulations for a two dimensional case are given to illustrate the ideas and the performance of the design.10 pages, 3 figuresOpticstext