[19p-225B-1~15] 3.11 Photonic structures and phenomena

[19p-225B-10] Room temperature current injection continuous-wave nanolaser utilized by ultrahigh-Q few-cell photonic crystal nanocavities

〇Eiichi Kuramochi^1,2, Masato Takiguchi^1,2, Koji Takeda^1,3, Takuro Fujii^1,3, Kengo Nozaki^1,2, Akihiko Shinya^1,2, Shinji Matsuo^1,3, Masaya Notomi^1,2 (1.NTT-NPC, 2.NTT-BRL, 3.NTT-DTL)

Keywords:photonic crystal, laser diode, nanolaser

Few-cell point-defect photonic crystal (PhC) nanocavities (such as L_x and H1 type cavities), have several unique characteristics including an ultra-small mode volume (V_m), a small device footprint advantageous for dense integration, and a large mode spacing advantageous for high spontaneous-emission coupling coefficient (β), which are promising for energy-efficient densely-integratable on-chip laser light sources enhanced by the cavity QED effect. To achieve this goal, a high quality factor (Q) is essential, but conventional few-cell point-defect cavities do not have a sufficiently high Q. Here we adopt a series of modified designs of L_x cavities with a buried heterostructure (BH) multi-quantum-well (MQW) active region that can achieve a high Q while maintaining their original advantages and fabricate current-injection laser devices. We have successfully observed continuous-wave (CW) lasing in InP-based L1, L2, L3 and L5 PhC nanocavities at room temparature with DC current injection lower than 10 µA. This is the first room-temperature current-injection CW lasing from any types of few-cell point-defect PhC nanocavities (L_x or H1 types). Our report marks an important step towards realizing a nanolaser diode with a high cavity-QED effect.