On-chip polarization-sensitive photodetectors offer unique opportunities for next-generation ultra-compact polarimeters. So far, mainstream approaches have relied on the anisotropic absorption of natural materials or artificial structures. However, such a model is inherently restricted by correlation between the polarization ratio (PR) and diattenuation, leading to small PR values (1 < PR < 10). Here, we report nanoantenna-mediated semimetal photodetectors, which enable configurable polarity transition by exploiting the vectorial and non-local photoresponse in semimetals. By tuning the orientation of nanoantennas, PR values vary from positive (unipolar regime) to negative (bipolar regime), covering all possible numbers (1 → ∞/−∞ → −1). In particular, the PR values at the polarity-transition point could approach infinity. Such a polarity transition hereby transcends the conventional PR–diattenuation relationship. Furthermore, our device allows the subtle measurement of polarization-angle perturbation down to 0.02° Hz^−1/2 in the mid-infrared range. Our findings highlight the potential of semimetals as a promising material platform for miniaturized polarimetry.

片上偏振敏感光电探测器为下一代超紧凑型偏振计提供了独特的机会。到目前为止，主流方法依赖于天然材料或人造结构的各向异性吸收。然而，这种模型本质上受到偏振比 (PR) 和衰减之间的相关性的限制，导致 PR 值较小 (1 < PR < 10)。在这里，我们报告了纳米天线介导的半金属光电探测器，它通过利用半金属中的矢量和非局部光响应来实现可配置的极性转换。通过调整纳米天线的方向，PR 值从正（单极状态）到负（双极状态）变化，涵盖所有可能的数字（1 → ∞/-∞ → -1）。特别是，极性转换点的 PR 值可能接近无穷大。这种极性转变因此超越了传统的 PR-衰减关系。此外，我们的设备允许对低至 0.02° Hz 的偏振角扰动进行精细测量^-1/2在中红外范围内。我们的研究结果突出了半金属作为微型偏振测量的有前途的材料平台的潜力。