Surface plasmon polariton direction change device, read/write head, laser-assisted magnetic recording apparatus, and optical circuit

Abstract

This invention provides a surface plasmon polariton direction change device (1) for changing a propagation direction of a surface plasmon polariton (5). The surface plasmon polariton direction change device (1) includes a metal film support member (2), and a first metal film (3) and a second metal film (4) which are provided on a predetermined surface of the metal film support member (2), are provided adjacently to each other, and are different from each other in effective refractive index. The surface plasmon polariton direction change device (1) is characterized in that the first metal film (3) and the second metal film (4) are provided so that, in at least a part of a boundary between the first metal film (3) and the second metal film (4), an angle θ formed between (i) a line perpendicular to the boundary and (ii) the propagation direction of the surface plasmon polariton (5) satisfies 0°<θ<90° or −90°<θ<0°, and (i) a surface of the first metal film (3) which is opposite to a surface in contact with the metal film support member (2) and (ii) a surface of the second metal film (4) which is opposite to a surface in contact with the metal film support member (2) are flush with each other.

Dependencies are inferred from the claim text.