Abstract: An optical device is provided. The optical device includes a substrate that has a top surface and a bottom surface. The optical device also includes a cover layer disposed on the substrate, and the cover layer has a top surface and a bottom surface. The top surface of the cover layer faces the bottom surface of the substrate. The optical device further includes a first meta structure disposed on the bottom surface of the substrate and a second meta structure disposed on the top surface of the cover layer. Moreover, the optical device includes a detector disposed on the bottom surface of the cover layer.

Abstract: An optical device is provided. The optical device includes a substrate, a waveguide layer, a first input grating, a first fold grating, and an isolation layer. The waveguide layer is disposed on the substrate. The first input grating is disposed in the waveguide layer. A first incident light passes through the first input grating to form a first light. The first fold grating is disposed in the waveguide layer. The first light passes through the first fold grating to form a first diffracted light in a first direction and a second diffracted light in a second direction. The isolation layer includes a first well array and is disposed on the waveguide layer. When the first diffracted light in the first direction travels to a first top portion corresponding to the first well array of the waveguide layer, the first diffracted light further passes through the first well array.