title: Light propagation in a Penrose unilluminable room.
abstract: Using the finite-difference time-domain method, propagation of light waves is studied in a Penrose unilluminable room. Such a room always has dark (unilluminated) regions, regardless of the position of a point source in it. However, in contrast to the predictions of ray dynamical simulations, a small amount of light propagates into the unilluminated regions via diffraction. We conjecture that this diffraction effect becomes more prominent as the size of the room decreases.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Fukushima
authors.forename: Koichiro
authors.initials: K
authors.lastname: Sakaguchi
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Tokuda