Zeng Jianhua, Zhou Yu, Fu Xiang, Yang Jianrong, Chen Yuxin, Hong Weiyi
Opt Express. 2025 Jun 30;33(13):27014-27025. doi: 10.1364/OE.566464.
The realization of switchable high- factors with intrinsic chirality is of paramount importance for various applications involving active and nonlinear metadevices that exhibit chiral responses. Here, we present a chiral metasurface that employs amorphous phase-change material, which enables the formation of quasi-bound states in the continuum characterized by inherent optical chirality. By simultaneously breaking both in-plane and out-of-plane symmetries, the metasurface supports multiple high- resonances that produce pronounced circular dichroism responses. Through eigenmode simulations and multipolar decomposition analysis, we demonstrate that the quasi-bound states in the continuum originate from various multipolar contributions. These modes are distinguished by sharp spectral features and circular dichroism values nearing unity, indicating near-perfect polarization selectivity. Furthermore, we illustrate that the intrinsic chirality and high- response can be actively deactivated by inducing the phase transition in the GeSbTe material to its crystalline state, which leads to significant optical losses and the suppression of the quasi-bound states in the continuum. Our findings establish a versatile and tunable photonic platform for dynamically reconfigurable chiroptical devices, offering promising prospects for applications in optical communication, biosensing, and quantum photonics.
对于涉及呈现手性响应的有源和非线性超材料器件的各种应用而言，实现具有本征手性的可切换高因子至关重要。在此，我们展示了一种采用非晶态相变材料的手性超表面，其能够形成以固有光学手性为特征的连续谱中的准束缚态。通过同时打破面内和面外对称性，该超表面支持多个高共振，从而产生明显的圆二色性响应。通过本征模模拟和多极分解分析，我们证明连续谱中的准束缚态源自各种多极贡献。这些模式的特征在于尖锐的光谱特征和接近1的圆二色性值，表明近乎完美的偏振选择性。此外，我们表明通过将GeSbTe材料诱导到其结晶态的相变，可以主动消除本征手性和高响应，这会导致显著的光学损耗并抑制连续谱中的准束缚态。我们的研究结果建立了一个用于动态可重构手性光学器件的通用且可调谐的光子平台，为光通信、生物传感和量子光子学中的应用提供了广阔前景。
