Controlled 1.3 – 1.55 µm coherent emission from micobelt-like optical cavities formed by rolled-up InAs quantum dot tubes

Abstract

High performance 1.3 and 1.55 µm micro- and nanoscale coherent light sources, with controlled emission wavelength, direction and polarization, are important for applications in chip-level optical communications, biosensing, and quantum information processing. However, an exact tailoring of the optical modes in conventional optical cavities, including photonic crystal, microdisks, and micropillars, is often difficult to achieve, due to the complicated top-down fabrication process. In this regard, a new class of optical cavities, with the use of rolled-up semiconductor tube structures, has been intensively investigated, which can exhibit directional emission, controlled polarization, and epitaxially smooth surface 1–4. In this work, we report on the achievement free-standing microbelt-like optical cavities by embedding a ridge-waveguide in a rolled-up tube structure, formed when a coherently strained InAs/GaAs or InAs/InP quantum dot (QD) layer is selectively released from the host substrate. We have achieved, for the first time, sharp polarized optical modes in the wavelength range of 1.3 – 1.55 µm from such nanoscale optical cavities at room temperature. An exact tailoring of the 3-dimensionally confined resonance modes is further demonstrated by varying the belt width using a single photolithography step.