Provided is a broadband photomixer technology that is a core to generate continuous frequency variable and pulsed terahertz waves. It is possible to enhance light absorptance by applying the transmittance characteristic of a 2D light crystal structure and it is possible to increase the generation efficiency of terahertz waves accordingly. Moreover, it is possible to implement a wide area array type terahertz photomixer by applying an interdigit structure and spatially properly arranging a light crystal structure having various cycles. Accordingly, it is possible to solve difficulty in thermal characteristic and light alignment by mitigating the high light density of a light absorption unit and low photoelectric conversion efficiency is drastically improved. In addition, the radiation pattern of terahertz waves may be electrically controlled through the present invention.