▎ 摘　　要

NOVELTY - The modulator has a quartz substrate (1), a silicon thin film (2) i.e. N-type silicon thin film, a silicon nano-needle array structure (3) and a graphene thin film (4) arranged in sequence manner. Thickness of the quartz substrate is about 300-500 pm. Thickness of the silicon thin film is about 80-200 pm. Resistivity of the silicon thin film is about 1000-5000 Qm. Diameter of nano needles of the silicon nano-needle array structure is about 100-300 nm. Length of the nano needles is about 3-8 pm. The graphene thin film is formed as P-type graphene. USE - Optically controlled terahertz modulator. ADVANTAGE - The modulator reduces insertion loss of terahertz wave by a device substrate and power consumption rate, and improves utilization rate of pump light by forming the silicon thin film on a surface of the quartz substrate and preparing the silicon nano-needle array structure, and takes a contact part of the silicon nano-needle array structure and graphene thin film as a working source area under stimulation of the pump light, and realizes effective regulation of the terahertz wave. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for an optically controlled terahertz modulator preparing method. DESCRIPTION OF DRAWING(S) - The drawing shows a front view of an optically controlled terahertz modulator. 1Quartz substrate 2Silicon thin film 3Silicon nano-needle array structure 4Graphene thin film