2019/04/25 by Xuefan Yin, Jicheng Jin, Yin, Xuefan +7
Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystals and Applications #Photonic and Optical Devices
paper · pdf · doi:10.48550/arxiv.1904.11464
openalex publication_date 2019/04/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Unidirectional radiation is important for a variety of optoelectronic\napplications. Many unidirectional emitters exist, but they all rely on the use\nof materials or structures that forbid outgoing waves, i.e. mirrors. Here, we\ntheoretically propose and experimentally demonstrate a class of resonances in\nphotonic crystal slabs, which only radiate towards a single side with no mirror\nplaced on the other side - we call them ``unidirectional bound states in the\ncontinuum". These resonances are found to emerge when a pair of half-integer\ntopological charges in the polarization field bounce into each other in the\nmomentum space. We experimentally demonstrate such resonances in the\ntelecommunication regime, where we achieve single-sided quality factor as high\nas 1.6e5, equivalent to a radiation asymmetry ratio of 27.7 dB. Our work\nrepresents a vivid example of applying topological principles to improve\noptoelectronic devices. Possible applications of our work include grating\ncouplers, photoniccrystal surface-emitting lasers, and antennas for light\ndetection and ranging.\n