近日，中国科学院长春光学精密机械与物理研究所的佟存柱及其研究小组取得一项新进展。经过不懈努力，他们首次演示1550nm低阈值三晶格光子晶体表面发射激光器的连续波工作。相关研究成果已于2024年2月5日在国际知名学术期刊《光：科学与应用》上发表。

本文中，研究人员首次展示了使用“三点阵光子晶体谐振器”实现的1.55μm光子晶体表面发射激光器的连续波工作。这种谐振器设计独特，通过叠加三个晶格点群来增强面内光反馈的强度。研究人员运用这种几何结构，与普通单晶格结构相比，面内180°耦合能力提升了三倍。经过详细的理论和实验研究，他们发现，与“单晶格”和“双晶格”光子晶体谐振器相比，这种新结构的阈值电流密度显著降低，从而验证了其设计原理的有效性。这一发现为光子晶体激光器的小型化提供了一种新的策略，对于推动光子晶体激光器在未来高速应用中的发展具有重大意义。

据悉，光子晶体表面发射激光器得益于窄光束发散，有望在日益发展的光通信和光探测与测距领域发挥重要作用。波长为1.55μm的激光器因其最小的光纤损耗和高的人眼安全阈值而受到特别关注。然而，在1.55μm波长处，高带间吸收显著降低了它们的性能。因此，需要更强的光反馈来降低其阈值，从而提高输出功率。为了实现这一目标，经常使用具有深孔和高介电对比度的光子晶体谐振器。然而，高对比度光子晶体的相关技术不可避免地使制造复杂化并降低了最终产量。

附：英文原文

Title: Continuous-wave operation of 1550 nm low-threshold triple-lattice photonic-crystal surface-emitting lasers

Author: Wang, Ziye, Liu, Xia, Wang, Pinyao, Lu, Huanyu, Meng, Bo, Zhang, Wei, Wang, Lijie, Wang, Yanjing, Tong, Cunzhu

Issue&Volume: 2024-02-05

Abstract: Benefitting from narrow beam divergence, photonic crystal surface-emitting lasers are expected to play an essential role in the ever-growing fields of optical communication and light detection and ranging. Lasers operating with 1.55μm wavelengths have attracted particular attention due to their minimum fiber loss and high eye-safe threshold. However, high interband absorption significantly decreases their performance at this 1.55μm wavelength. Therefore, stronger optical feedback is needed to reduce their threshold and thus improve the output power. Toward this goal, photonic-crystal resonators with deep holes and high dielectric contrast are often used. Nevertheless, the relevant techniques for high-contrast photonic crystals inevitably complicate fabrication and reduce the final yield. In this paper, we demonstrate the first continuous-wave operation of 1.55μm photonic-crystal surface-emitting lasers by using a ‘triple-lattice photonic-crystal resonator’, which superimposes three lattice point groups to increase the strength of in-plane optical feedback. Using this geometry, the in-plane 180° coupling can be enhanced threefold compared to the normal single-lattice structure. Detailed theoretical and experimental investigations demonstrate the much lower threshold current density of this structure compared to ‘single-lattice’ and ‘double-lattice’ photonic-crystal resonators, verifying our design principles. Our findings provide a new strategy for photonic crystal laser miniaturization, which is crucial for realizing their use in future high-speed applications.

DOI: 10.1038/s41377-024-01387-4

Source: https://www.nature.com/articles/s41377-024-01387-4