2018年第79回応用物理学会秋季学術講演会

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3 光・フォトニクス » 3.11 フォトニック構造・現象

[18a-225B-1~9] 3.11 フォトニック構造・現象

2018年9月18日(火) 09:30 〜 11:45 225B (2Fラウンジ2)

野田 進(京大)

11:00 〜 11:15

[18a-225B-7] Towards Topological Laser Based on Dielectric Photonic Crystals

〇(P)Xiao-Chen Sun1、Xiao Hu1 (1.WPI-MANA,NIMS)

キーワード:photonic crystal, topological insulator, laser

The photonic topological insulators provide ideal platforms for photonic applications, which always require defect-tolerant properties to reduce losses. However, most photonic topological states work in the microwave frequency band, and require external magnetic field, which hinder their usages in applications.
Wu and Hu proposed a scheme to achieve topological photonic crystals by using dielectric materials. Starting from honeycomb structure, they adjust the locations of pillars and get a pair of topological edge states with opposite orbital angular momenta, which play the role of pseudospin, at the interface between topological and trivial photonic crystals. Because only dielectric materials are used, this scheme can be pushed to the optical frequency band and no external magnetic field is required.
In the present work, as the cavity for lasing, we construct the topological interface states achieved in the above scheme. We can write the equation of motion in a tight binding picture. By adjusting the real-valued hopping coefficients in the equation, we can design topological and trivial photonic crystals, between which there yield topological interface states.
By numerical solving the above equation, we successfully observe a pseudospin-dominated lasing behavior where the topological interface states are active. Single-mode lasing is confirmed in a considerable range of gain value.
To summarize, we have constructed a lasing system with the cavity composed by the topological interface channel in dielectric photonic crystals. Our system shows typical pseudospin-dominated lasing phenomena. We are going to explore the possibility of this scheme as a promising platform for laser design.