A novel tunable terahertz metamaterials polarization converter (PC) is presented in this paper, whose operating band can be extended by the innovative band splicing technology (combine different PCs with different bands to make the bands splice together) and adjusted into a broadband absorber via adjusting the temperature. Four different units are combined to form a supercell and the phases can be matched through the phase compensation optimization technology. It is a noteworthy finding that the working band becomes wider significantly as the four different working bands join together by the band splicing technology. At the same time, under the action of vanadium dioxide (VO₂), the amplitude of reflectance is regulated through the temperature field. The simulation results display that below the critical temperature of 341 K (68 °C), VO₂ is treated as an insulator (σ = 20 S/m), the cross-polarization conversion (CPC) can be achieved in the frequency range of 0.91–1.67 THz, whose relative bandwidth (RB) reaches 58.9%. The operating band is expanded compared with four single small units with similar basic structure but different parameters, whose bands are 1.11–1.714 THz, 1.08–1.68 THz, 1.13–1.7 THz, and 1.024–1.608 THz with polarization conversion ratios (PCRs) above 0.9. At high temperature which exceeds the critical temperature, VO₂ turns into metal (σ = 200,000 S/m) and the PC is switched into an ultra-broadband absorber with the operating band of 0.744–1.782 THz (the relative bandwidth (RB) of 82.1%), which is significantly different from that at low temperature. Without complex geometry, the reflected PC can broaden the bandwidth on the existing basis. Besides, this metamaterial structure builds a bridge between the polarization converter and the absorber by taking advantage of the non-contact control method, which strengthens the degree of freedom of the electromagnetic metamaterials that would further create a greatly fertile ground for their applications.

本文提出了一种新型的可调谐太赫兹超材料极化转换器（PC），其工作频带可以通过创新的频带拼接技术来扩展（将具有不同频带的不同PC组合在一起以使频带拼接在一起），并通过调整将其调整为宽带吸收器气温。四个不同的单元组合在一起形成一个超级单元，并且可以通过相位补偿优化技术对相位进行匹配。值得注意的发现是，随着四个不同的工作频带通过频带拼接技术连接在一起，工作频带显着变宽。同时，在二氧化钒（VO ₂），反射率的幅度是通过温度场来调节的。仿真结果表明，在341 K（68°C）的临界温度以下，VO ₂被视为绝缘体（σ  = 20 S / m），在以下频率范围内可以实现交叉极化转换（CPC）。 0.91–1.67 THz，其相对带宽（RB）达到58.9％。与具有相似基本结构但参数不同的四个单个小型装置相比，工作频带得到了扩展，其频带分别为1.11–1.714 THz，1.08–1.68 THz，1.13–1.7 THz和1.024–1.608 THz，且偏振转换比（PCR）高于0.9。在超过临界温度的高温下，VO ₂变成金属（σ = 200,000 S / m），并且将PC切换为工作频带为0.744–1.782 THz（相对带宽（RB）为82.1％）的超宽带吸收器，这与低温下的显着不同。无需复杂的几何结构，反射的PC可以在现有基础上扩展带宽。此外，这种超材料结构利用非接触控制方法在极化转换器和吸收器之间架起了一座桥梁，从而增强了电磁超材料的自由度，从而为它们的应用进一步创造了肥沃的土壤。