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Ultrathin Colloidal Quantum Dot Films for Optical Amplification: The Role of Modal Confinement and Heat Dissipation
Author(s) -
Koh Weonkyu,
Lee Jaesoong,
Cho KyungSang,
Roh YoungGeun
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201700726
Subject(s) - quantum dot , lasing threshold , materials science , optoelectronics , waveguide , photonics , dielectric , laser , quantum dot laser , plasmon , active laser medium , optics , semiconductor laser theory , physics , semiconductor , laser power scaling , wavelength
We demonstrate optical pumping lasers based on colloidal quantum dots, with a very thin geometry consisting of a ≈20 nm thick film. Obstacles in ultrasmall laser devices come from the limitation of gain materials and the size of cavities for lasing modes, which requires a minimum thickness of the gain media (typically greater than 50–100 nm). Here we introduce dielectric waveguide structures with a high refractive index, in order to reduce the thickness of quantum dot gain media as well as their threshold energy (≈39 % compared to the original gain medium). Finite‐difference time‐domain simulations show that the modal confinement factor of thinner quantum dot films can be improved by the presence of an adjacent waveguide layer. We also discuss the possible role of dielectric waveguide layers for efficient heat dissipation during optical pumping. Integrating an extremely thin colloidal quantum dot gain medium into optical waveguides is a promising platform for downscaling on‐chip photonic integrated devices, as well as investigating extreme interactions between light and matter such as surface plasmon–photon coupling.