Observing exceptional point degeneracy of radiation with electrically pumped photonic crystal coupled-nanocavity lasers

抄録

<jats:p>Controlling gain and loss of coupled optical cavities can induce non-Hermitian degeneracies of eigenstates, called exceptional points (EPs). Various unconventional phenomena around EPs have been reported, and are expected to incorporate extra functionalities into photonic devices. The eigenmode exactly under EP degeneracy is also predicted to exhibit enhanced radiation. However, such responses have yet to be observed in on-chip lasers because of both the limited controllability of their gain and loss and the lifting of degeneracy by pump-induced cavity detuning. Here, we report, to the best of our knowledge, the first non-Hermitian nanophotonic platform based on two electrically pumped photonic crystal lasers and its spontaneous emission at EP degeneracy. Systematically tuned and independent current injection to our wavelength-scale active heterostructure cavities enables us to demonstrate the clear EP phase transition of their spontaneous emission, accompanied with the spectral coalescence of coupled modes and reversed pump dependence of the intensity. Furthermore, we find experimentally and confirm theoretically the peculiar squared Lorentzian emission spectrum very near the exact EP, which indicates a four-fold enhancement of the photonic local density of states induced purely by the degeneracy. Our results open a new pathway to engineer the light–matter interaction by non-Hermiticity and explore larger reconfigurable laser arrays for further non-Hermitian features and physics.</jats:p>

収録刊行物

  • Optica

    Optica 8 (2), 184-, 2021-02-03

    Optica Publishing Group

被引用文献 (5)*注記

もっと見る

参考文献 (53)*注記

もっと見る

関連プロジェクト

もっと見る

詳細情報 詳細情報について

問題の指摘

ページトップへ