Two-dimensional Photonic Crystal Nanocavities Research Articles

Nano-engineering approaches to self-assembled InAs quantum dot laser medium

A number of nano-engineering methods are proposed and tested to improve optical properties of a laser gain medium using the self-assembled InAs quantum dot (QD) ensemble. The laser characteristics of concern include higher gain, larger modulation bandwidth, higher efficiency at elevated temperatures, higher thermal stability, and enhanced reliability. The focus of this paper is on the management of QD properties through design and molecular beam epitaxial growth and modification of QD heterostructures. This includes digital alloys as high-quality wide-bandgap barrier; under- and overlayers with various compositions to control the dynamics of QD formation and evolution on the surface; shape engineering of QDs to improve electron-hole overlap and reduce inhomogeneous broadening; band engineering of QD heterostructures to enhance the carrier localization by reduction of thermal escape from dots; as well as tunnel injection from quantum wells (QWs) to accelerate carrier transfer to the lasing state. Beneficial properties of the developed QD media are demonstrated at room temperature in laser diodes with unsurpassed thermal stability with a characteristic temperature of 380 K, high waveguide modal gain >50 cm−1, unsurpassed defect tolerance over two orders of magnitude higher than that of QWs typically used in lasers, and efficient emission from a two-dimensional (2-D) photonic crystal nanocavity.

Optical Characteristics of Two-Dimensional Photonic Crystal Slab Nanocavities with Self-Assembled InAs Quantum Dots for 1.3 µm Light Emission

We reported the fabrication and optical characteristics of two-dimensional photonic crystal slab nanocavities with a single defect containing self-assembled InAs quantum dots for 1.3 µm light emission. We observed an enhanced luminescence and three sharp peaks from a single defect of a two-dimensional photonic crystal slab nanocavity simultaneously at one measurement step by using self-assembled InAs quantum dots as the active materials. Comparison of the experimental results with the calculation results shows that the observed three sharp peaks originate from the defect modes with different symmetries in a single defect of the two-dimensional photonic crystal slab.

Optical characterization of two-dimensional photonic crystal cavities with indium arsenide quantum dot emitters

We have characterized the modes within two-dimensional photonic crystal nanocavities with self-organized indium arsenide quantum dots as an active material. Highly localized donor mode resonances with 3 to 5 nm linewidth were observed when spatially selective optical pumping the cavities. These modes could be lithographically tuned from 1100 to 1300 nm. Other, more extended modes, were also characterized and exhibited narrower resonance linewidths ranging from 0.6 to 2 nm.