Cong Longqing, Han Jiaguang, Zhang Weili, Singh Ranjan
Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, 300072, China.
Nat Commun. 2021 Nov 26;12(1):6940. doi: 10.1038/s41467-021-27014-z.
Losses are ubiquitous and unavoidable in nature inhibiting the performance of most optical processes. Manipulating losses to adjust the dissipation of photons is analogous to braking a running car that is as important as populating photons via a gain medium. Here, we introduce the transient loss boundary into a photon populated cavity that functions as a 'photon brake' and probe photon dynamics by engineering the 'brake timing' and 'brake strength'. Coupled cavity photons can be distinguished by stripping one photonic mode through controlling the loss boundary, which enables the transition from a coupled to an uncoupled state. We interpret the transient boundary as a perturbation by considering both real and imaginary parts of permittivity, and the dynamic process is modeled with a temporal two-dipole oscillator: one with the natural resonant polarization and the other with a frequency-shift polarization. The model unravels the underlying mechanism of concomitant coherent spectral oscillations and generation of tone-tuning cavity photons in the braking process. By synthesizing the temporal loss boundary into a photon populated cavity, a plethora of interesting phenomena and applications are envisioned such as the observation of quantum squeezed states, low-loss nonreciprocal waveguides and ultrafast beam scanning devices.
损耗在自然界中无处不在且不可避免，会抑制大多数光学过程的性能。操控损耗以调节光子的耗散，类似于给行驶中的汽车刹车，这与通过增益介质填充光子一样重要。在此，我们将瞬态损耗边界引入充满光子的腔中，该腔起到“光子刹车”的作用，并通过设计“刹车时机”和“刹车强度”来探测光子动力学。通过控制损耗边界去除一个光子模式，可以区分耦合腔光子，这使得从耦合状态转变为非耦合状态成为可能。我们通过考虑介电常数的实部和虚部，将瞬态边界解释为一种微扰，并使用时间双偶极子振荡器对动态过程进行建模：一个具有自然共振极化，另一个具有频移极化。该模型揭示了制动过程中伴随的相干光谱振荡和调谐腔光子产生的潜在机制。通过将时间损耗边界合成到充满光子的腔中，可以设想出大量有趣的现象和应用，例如量子压缩态的观测、低损耗非互易波导和超快光束扫描装置。
