Choi Jihoon, Hong Young Ki, Noh Heeso
Department of Physics, Kookmin University, Seoul 02707, Republic of Korea.
Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea.
Nanophotonics. 2024 Jan 25;13(3):377-385. doi: 10.1515/nanoph-2023-0788. eCollection 2024 Feb.
Coherent perfect absorption (CPA) has been studied in various fields, such as metasurface, photonics, and acoustics, because of its ability to perfectly absorb light at a specific wavelength. However, the narrow bandwidth of CPA makes its application to on-chip photonics challenging. This limitation can be overcome by using a broadband resonator. Here, we demonstrate the coherent perfect loss (CPL) with respect to a single and broadband resonator at photonic crystal nanobeam. By using the finite element method, both cases of the CPL were simulated and optimized for the single and broadband resonators. In the optimized structure, a CPL occurs for both resonators. These results confirm that the perfect loss region for the broadband resonator is wider than that for the single resonator. These results are experimentally verified by fabricating both cases of CPL cases on a silicon-on-insulator by using electron beam lithography. An almost perfect loss of more than 95 % is observed for both single and broadband CPLs. Furthermore, the almost perfect loss region at the broadband resonator broadens more than that at the single resonator. The optimized structure for CPL has the potential for easy applications to on-chip photonics, such as optical switches, modulators, sensors, and logic gates.
由于相干完美吸收（CPA）能够在特定波长下完美吸收光，因此已在超表面、光子学和声学等各个领域得到研究。然而，CPA的窄带宽使其在片上光子学中的应用面临挑战。通过使用宽带谐振器可以克服这一限制。在这里，我们展示了光子晶体纳米光束中关于单个和宽带谐振器的相干完美损耗（CPL）。通过使用有限元方法，对单个和宽带谐振器的CPL情况进行了模拟和优化。在优化结构中，两个谐振器都出现了CPL。这些结果证实，宽带谐振器的完美损耗区域比单个谐振器的更宽。通过使用电子束光刻在绝缘体上硅上制造这两种CPL情况，对这些结果进行了实验验证。对于单个和宽带CPL，都观察到了超过95%的几乎完美的损耗。此外，宽带谐振器处的几乎完美损耗区域比单个谐振器处的更宽。CPL的优化结构具有易于应用于片上光子学的潜力，如光开关、调制器、传感器和逻辑门。
