Broadband emission centered at ∼1 µm with a Gaussian‐like spectrum by stacking In‐flushed QD layers

Abstract

AbstractWe have grown a stack of In‐flushed InAs quantum dot (QD) layers to realize a broadband emission centered at ∼1 µm with a Gaussian‐like spectrum as a light source for optical coherence tomography (OCT). The In‐flush process, which enables control of the height of the QD, was optimized to control the emission wavelength and intensity of self‐assembled InAs/GaAs QDs. A partial capping layer of GaAs was deposited on as‐grown InAs/GaAs QDs with various thicknesses (dcap), and a rapid annealing of the sample was executed with the proper annealing temperature. By optimizing dcap and the annealing temperature for each QD layer, a broadband Gaussian‐like spectrum with a 102‐nm‐bandwidth was obtained. The coherence function of the emission spectrum exhibits a 4.5‐µm axial resolution for OCT images without distinct side lobes. These results demonstrate the effectiveness of the In‐flushed QDs as a light source to obtain high‐quality OCT images. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)