Telecommunications and polarimetry both require the active control of the polarization of light. Currently, this is done by combining intrinsically anisotropic materials with tunable isotropic materials into heterostructures using complicated fabrication techniques owing to the lack of scalable materials that possess both properties. Tunable birefringent and dichromic materials are scarce and rarely available in high-quality thin films over wafer scales. Here we report semiconducting, highly aligned, single-walled carbon nanotubes (SWCNTs) over 4″ wafers with normalized birefringence and dichroism values of 0.09 and 0.58, respectively. The real and imaginary parts of the refractive index of these SWCNT films are tuned by up to 5.9% and 14.3% in the infrared at 2,200 nm and 1,660 nm, respectively, using electrostatic doping. Our results suggest that aligned SWCNTs are among the most anisotropic and tunable optical materials known and open new avenues for their application in integrated photonics and telecommunications.

电信和偏振测量都需要主动控制光的偏振。目前，这是通过使用复杂的制造技术将本质各向异性材料与可调各向同性材料组合成异质结构来实现的，因为缺乏具有这两种特性的可扩展材料。可调谐双折射和二色性材料很稀缺，并且很少可用于晶圆级的高质量薄膜。在这里，我们报告了 4 英寸晶圆上的半导体、高度排列、单壁碳纳米管 (SWCNT)，其归一化双折射和二色性值分别为 0.09 和 0.58。使用静电掺杂，这些 SWCNT 薄膜在 2,200 nm 和 1,660 nm 红外波段的折射率实部和虚部分别调节高达 5.9% 和 14.3%。我们的研究结果表明，排列好的单壁碳纳米管是已知的各向异性和可调性最强的光学材料之一，并为其在集成光子学和电信领域的应用开辟了新的途径。