Non-invasive, high-throughput spectroscopic techniques can identify chiral indices (n,m) of carbon nanotubes down to the single-tube level^1,2,3,4,5,6. Yet, for complete characterization and to unlock full functionality, the handedness, the structural property associated with mirror symmetry breaking, also needs to be identified accurately and efficiently^{7,8,9,10,11,12,13,14}. So far, optical methods fail in the handedness characterization of single nanotubes because of the extremely weak chiroptical signals (roughly 10⁻⁷) compared with the excitation light^15,16. Here we demonstrate the complete structure identification of single nanotubes in terms of both chiral indices and handedness by Rayleigh scattering circular dichroism. Our method is based on the background-free feature of Rayleigh scattering collected at an oblique angle, which enhances the nanotube’s chiroptical signal by three to four orders of magnitude compared with conventional absorption circular dichroism. We measured a total of 30 single-walled carbon nanotubes including both semiconducting and metallic nanotubes and found that their absolute chiroptical signals show a distinct structure dependence, which can be qualitatively understood through tight-binding calculations. Our strategy enables the exploration of handedness-related functionality of single nanotubes and provides a facile platform for chiral discrimination and chiral device exploration at the level of individual nanomaterials.

非侵入性、高通量光谱技术可以识别碳纳米管的手性指数 ( n , m ) 低至单管水平^1,2,3,4,5,6。然而，为了完整的表征和解锁全部功能，还需要准确有效地识别与镜像对称破坏相关的手性，即结构特性^{7,8,9,10,11,12,13,14}。到目前为止，由于手性光信号（大约 10 ^-7）与激发光^{15,16相比极其微弱，因此光学方法无法对单个纳米管进行旋向性表征}. 在这里，我们通过瑞利散射圆二色性证明了单纳米管在手性指数和手性方面的完整结构识别。我们的方法基于以斜角收集的瑞利散射的无背景特征，与传统的吸收圆二色性相比，该方法将纳米管的手性信号增强了三到四个数量级。我们测量了总共 30 个单壁碳纳米管，包括半导体和金属纳米管，发现它们的绝对手性信号显示出明显的结构依赖性，这可以通过紧束缚计算来定性地理解。