Nomura Masahiro, Kumagai Naoto, Iwamoto Satoshi, Ota Yasutomo, Arakawa Yasuhiko
Institute for Nano Quantum Information Electronics, Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
Opt Express. 2009 Aug 31;17(18):15975-82. doi: 10.1364/OE.17.015975.
We demonstrate a photonic crystal nanocavity laser essentially driven by a self-assembled InAs/GaAs single quantum dot gain. The investigated nanocavities contain only 0.4 quantum dots on an average; an ultra-low density quantum dot sample (1.5 x 10(8) cm(-2)) is used so that a single quantum dot can be isolated from the surrounding quantum dots. Laser oscillation begins at a pump power of 42 nW under resonant condition, while the far-detuning conditions require ~145 nW for lasing. This spectral detuning dependence of laser threshold indicates substantial contribution of the single quantum dot to the total gain. Moreover, photon correlation measurements show a distinct transition from anti-bunching to Poissonian via bunching with the increase of the excitation power, which is also an evidence of laser oscillation using the single quantum dot gain.
我们展示了一种本质上由自组装InAs/GaAs单量子点增益驱动的光子晶体纳米腔激光器。所研究的纳米腔平均仅包含0.4个量子点；使用超低密度量子点样品（1.5×10⁸ cm⁻²），以便单个量子点能够与周围量子点隔离开来。在共振条件下，泵浦功率为42 nW时开始激光振荡，而在远失谐条件下，激光发射需要约145 nW。激光阈值的这种光谱失谐依赖性表明单量子点对总增益有显著贡献。此外，光子关联测量表明，随着激发功率的增加，通过聚束从反聚束到泊松分布有明显转变，这也是使用单量子点增益进行激光振荡的一个证据。
