标题： 宽带偶极子在色散光子时间晶体中的吸收 显示英文标题

标题： Broadband Dipole Absorption in Dispersive Photonic Time Crystals

摘要： 在时间上周期性调制的光子介质，称为光子时间晶体（PTCs），因其能够开启承载放大模式的动量带隙而引起了广泛关注。然而，这些动量带隙通常仅在系统的参数共振条件下出现，这限制了由放大产生的许多特性仅存在于一个狭窄的频率带宽内。此外，它们伴随着奇异点（EPs），使得其分析更加复杂。在此，我们表明，仔细考虑色散和吸收可以克服这些问题。通过研究嵌入色散和吸收性PTC中的点偶极子的耗散功率，我们揭示了时间调制能够在无EPs的宽带频率窗口内将偶极子发射转换为偶极子吸收。我们证明这种效应是普遍的，从弱调制强度到低调制频率都会发生，并且可以在各种材料平台上实现。此外，我们展示了根据调制参数的不同，可以实现宽带抑制和耗散功率的大幅增加的可能性。 显示英文摘要

摘要： Photonic media modulated periodically in time, termed photonic time crystals (PTCs), have attracted considerable attention for their ability to open momentum bandgaps hosting amplifying modes. These momentum gaps, however, generally appear only at the system's parametric resonance condition which constrain many features derived from amplification to a narrow frequency band. Moreover, they are accompanied by exceptional points (EPs) that render their analysis more intricate. Here, we show that a careful consideration of dispersion and absorption can overcome these issues. By investigating the dissipated power of a point-dipole embedded in a dispersive and absorptive PTC, we unveil that temporal modulation enables the conversion of dipole emission into dipole absorption within a broadband frequency window free of EPs. We demonstrate that this effect is general and occurs from weak modulation strengths to low modulation frequencies, and can be achieved for various material platforms. Moreover, we show the possibility of both broadband inhibition and large increase of dissipated power, depending on the modulated parameter.