The present disclosure relates to a single OPA (optical phased array) device including a light source; a waveguide which extends from the light source to allow light incident from the light source to pass through; a plurality of modulators which is disposed in the waveguide to modulate a phase of light in the waveguide; a two-dimensional material layer which passes or absorbs light incident from the light source; and an electrode which supplies charges to the two-dimensional material layer, in which the light incident from the light source passes through the two-dimensional material layer, the waveguide, and the modulator and is reflected by an external target of the single OPA device to pass through the modulator and the waveguide, and then absorbed by the two-dimensional material layer.