Patent ID: 8345527

Claim:
A controller comprising a control element so that a phase of incident light applied to the control element is controlled, wherein the control element includes a metal structure composed of a single member having different sizes in a first direction and a second direction respectively, the second direction being perpendicular to the first direction within an electric-field vibration plane of the incident light; a wavelength of the incident light includes a plasmon resonance wavelength possessed by the metal structure; and the incident light is linearly polarized light, wherein a transmission spectrum of the linearly polarized light is based on one of a major axis and a minor axis in which the linearly polarized light is applied to, wherein when the plasmon resonance wavelength in the first direction is shorter than the plasmon resonance wavelength in the second direction, a polarization axis of the incident light rotates at a wavelength near the plasmon resonance wavelength in the first direction, which is shorter than the plasmon resonance wavelength in the first direction and at which the phase difference becomes zero, or a wavelength near the plasmon resonance wavelength in the second direction, which is longer than the plasmon resonance wavelength in the second direction and at which the phase difference becomes zero.