Inkjet-printed random coding metal particles for modulation enhancement of an optical-controlled terahertz wave modulator

The modulation enhancement performance of inkjet-printed random coding metal particles lattice is studied in this paper. By optimizing duty ratio of metal particles lattice, the modulation depth of optical-controlled terahertz wave modulators can reach to 62 and 83 % with periodic configuration and random coding structure, respectively. Their optimized modulation depths are nearly 1.3 times and 1.7 times of reference device, respectively. The random coding device has better performance mainly because the random distribution lattice leads more incident pumping light to be absorbed by substrate material due to the multiple scattering. Besides, the influence of different solvent heating treatments on modulation depth is also studied in this paper. The heating treatment with hotplate has more opportunity to form high quality metal particles and greatly improves the performance of modulator. Our study not only provides an alternative route to develop high performance optical-controlled terahertz wave modulators, but also brings an alternative way to other research area such as terahertz antenna, solar cell, etc.