Broadband waveplate device based on optical phase modulation and fabrication method therefor

A method of fabrication a broadband waveplate device, the method comprising:

• forming, on a substrate, a multiple-quantum-well layer in which well layers and barrier layers are alternately stacked;
• forming a first conductive layer on the multiple-quantum-well layer;
• removing the substrate;
• forming a temporary conductive layer on a surface of the multiple-quantum-well layer in a direction away from the first conductive layer;
• forming a sacrificial layer on the temporary conductive layer;
• forming, in the sacrificial layer, a plurality of openings parallel to one another;
• forming an antenna layer having a shape of a plurality of stripes parallel to one another, by removing portions of the temporary conductive layer exposed through the plurality of openings of the sacrificial layer;
• and
• removing the sacrificial layer.

A broadband waveplate device comprising:

• a first conductive layer;
• a multiple-quantum-well layer in which well layers and barrier layers are alternately stacked, disposed on the first conductive layer;
• an antenna layer disposed on the multiple-quantum-well layer and having a shape of a plurality of stripes parallel to one another;
• and
• an actuator located such that the first conductive layer is interposed between the actuator and the multiple-quantum-well layer, the actuator capable of adjusting a direction of the plurality of stripes of the antenna layer with respect to incident light.