AI 中文总结
本文提出利用分布式布拉格反射镜腔激活胶体CdSe-CdS纳米片的轻空穴激子发射，通过腔共振匹配实现低激发功率下的轻空穴耦合发射，建立了腔工程获取辐射抑制光学态的通用方法。
AI 中文摘要
轻空穴（LH）激子可提供量子光子学和手性光-物质相互作用核心的明确定义的偏振和自旋自由度，但实现轻空穴发射极具挑战，因为轻空穴态能量不利且通常以非辐射方式弛豫。现有获取轻空穴激子的策略依赖于通过应变、形状各向异性或压电场修改电子带结构，这些方法具有材料特异性且合成后可调性有限。本文展示了一种全光学方法，利用分布式布拉格反射镜（DBR）腔激活胶体CdSe-CdS纳米片（NPLs）中的轻空穴激子发射，无需改变基础带结构。在无微腔模式时，低激发功率下系统呈现重空穴（HH）态的放大自发发射，无检测到的轻空穴发射；通过将腔共振与轻空穴激子光谱匹配，轻空穴耦合发射在显著更低的激发功率下出现。温度相关光谱显示，通过激子-腔失谐可实现轻空穴与重空穴耦合发射之间的可逆切换，而偏振分辨和光谱分辨时间分辨光致发光测量提供了区分腔耦合轻空穴与重空穴发射通道的独立证据。这些发现确立了腔工程作为一种通用材料层面方法，用于获取辐射抑制的光学态。
英文摘要
Light-hole (LH) excitons provide access to well-defined polarization and spin degrees of freedom that are central to quantum photonics and chiral light-matter interactions. Achieving LH emission is challenging because LH states are energetically unfavoured and typically relax non-radiatively. Existing strategies to access LH excitons rely on modifying the electronic band structure through strain, shape anisotropy, or piezoelectric fields, approaches that are material-specific and offer limited post-synthesis tunability. Here we demonstrate an all-photonic route to activate LH exciton emission in colloidal CdSe-CdS nanoplatelets (NPLs) using a distributed Bragg reflector (DBR) cavity, without altering the underlying band structure. In the absence of a cavity mode, the system exhibits amplified spontaneous emission from heavy-hole (HH) states without detectable LH emission at low excitation powers. By spectrally matching a cavity resonance to the LH exciton, cavity-coupled LH emission emerges at significantly lower excitation powers. Temperature-dependent spectroscopy reveals reversible switching between LH- and HH-coupled emission through exciton-cavity detuning, while polarization-resolved and spectrally resolved time-resolved photoluminescence measurements provide independent evidence distinguishing the cavity-coupled LH and HH emission channels. These findings establish cavity engineering as a general materials-level approach for accessing radiatively suppressed optical states.
