Lin Xiao, Hu Hao, Easo Sajan, Yang Yi, Shen Yichen, Yin Kezhen, Blago Michele Piero, Kaminer Ido, Zhang Baile, Chen Hongsheng, Joannopoulos John, Soljačić Marin, Luo Yu
Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, ZJU-Hangzhou Global Science and Technology Innovation Center, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China.
International Joint Innovation Center, ZJU-UIUC Institute, Zhejiang University, Haining, 314400, China.
Nat Commun. 2021 Sep 21;12(1):5554. doi: 10.1038/s41467-021-25822-x.
Cherenkov detectors enable a valuable tool to identify high-energy particles. However, their sensitivity and momentum coverage are limited by the refractive index of host materials. Especially, identifying particles with energy above multiple gigaelectronvolts requires host materials with a near-unity refractive index, which are limited to bulky gas chambers. Overcoming this fundamental material limit is important for future particle detectors yet remains a long-standing challenge. Here, we propose a different paradigm for Cherenkov detectors that utilizes the broadband angular filter made from stacks of variable one-dimensional photonic crystals. Owing to the Brewster effect, the angular filter is transparent only to Cherenkov photons from a precise incident angle. Particle identification is achieved by mapping each Cherenkov angle to the peak-intensity position of transmitted photons in the detection plane. Such angular filtering effect, although decreases the photon number collected in the detection plane, enables the realization of a non-dispersive pseudo refractive index over the entire visible spectrum. Moreover, the pseudo refractive index can be flexibly designed to different values close to unity. Our angular-selective Brewster paradigm offers a feasible solution to implement compact and highly sensitive Cherenkov detectors especially in beam lines with a small angular divergence using regular dielectrics.
切伦科夫探测器是识别高能粒子的重要工具。然而，其灵敏度和动量覆盖范围受主体材料折射率的限制。特别是，识别能量高于多个吉电子伏特的粒子需要折射率接近1的主体材料，而这类材料仅限于大型气室。克服这一基本材料限制对未来的粒子探测器至关重要，但仍是一个长期挑战。在此，我们为切伦科夫探测器提出了一种不同的范例，即利用由可变一维光子晶体堆叠制成的宽带角度滤波器。由于布儒斯特效应，该角度滤波器仅对来自精确入射角的切伦科夫光子透明。通过将每个切伦科夫角映射到检测平面中透射光子的峰值强度位置来实现粒子识别。这种角度滤波效应虽然会减少检测平面中收集的光子数量，但能在整个可见光谱范围内实现非色散伪折射率。此外，伪折射率可以灵活设计为接近1的不同值。我们的角度选择性布儒斯特范例为实现紧凑且高灵敏度的切伦科夫探测器提供了可行的解决方案，特别是在使用常规电介质、角发散较小的束流线上。
