Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating

Since optical gain was observed from colloidal quantum dots (CQDs), research on CQD lasing has been focused on the CQDs themselves as gain materials and their coupling with optical resonators. Combining the advantages of a CQD gain medium and optical microcavity in a laser device is desirable. Here,...

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Main Authors: Gao, Yuan, Tobing, Landobasa Yosef Mario, Kiffer, Aurélien, Zhang, Dao Hua, Dang, Cuong, Demir, Hilmi Volkan
Other Authors: School of Electrical and Electronic Engineering
Format: Article
Language:English
Published: 2017
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Online Access:https://hdl.handle.net/10356/84891
http://hdl.handle.net/10220/43490
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-848912023-02-28T20:02:37Z Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating Gao, Yuan Tobing, Landobasa Yosef Mario Kiffer, Aurélien Zhang, Dao Hua Dang, Cuong Demir, Hilmi Volkan School of Electrical and Electronic Engineering School of Physical and Mathematical Sciences LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays CNRS International NTU THALES Research Alliances Colloidal quantum dot Lasing Since optical gain was observed from colloidal quantum dots (CQDs), research on CQD lasing has been focused on the CQDs themselves as gain materials and their coupling with optical resonators. Combining the advantages of a CQD gain medium and optical microcavity in a laser device is desirable. Here, we show concentric circular Bragg gratings intimately incorporating CdSe/CdZnS/ZnS gradient shell CQDs. Because of the strong circularly symmetric optical confinement in two dimensions, the output beam CQD-based circular grating distributed feedback laser is found to be highly spatially coherent and azimuthally polarized with a donut-like cross section. We also observe the strong modification of the photoluminescence spectrum by the grating structures, which is associated with modification of optical density of states. This effect confirmed the high quality of the resonator that we fabricated and the spectral overlap between the optical transitions of the emitter and resonance of the cavity. Single mode lasing has been achieved under a quasi-continuous pumping regime, while the position of the lasing mode can be conveniently tuned via adjusting the thickness of the CQD layer. Moreover, a unidirectional output beam can be observed as a bright circular spot on a screen without any collimation optics, presenting a direct proof of its high spatial coherence. NRF (Natl Research Foundation, S’pore) ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore) EDB (Economic Devt. Board, S’pore) Accepted version 2017-07-28T03:15:17Z 2019-12-06T15:53:09Z 2017-07-28T03:15:17Z 2019-12-06T15:53:09Z 2016 Journal Article Gao, Y., Tobing, L. Y. M., Kiffer, A., Zhang, D. H., Dang, C., & Demir, H. V. (2016). Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating. ACS Photonics, 3(12), 2255-2261. https://hdl.handle.net/10356/84891 http://hdl.handle.net/10220/43490 10.1021/acsphotonics.6b00712 en ACS Photonics © 2016 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by ACS Photonics, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1021/acsphotonics.6b00712]. 13 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Colloidal quantum dot
Lasing
spellingShingle Colloidal quantum dot
Lasing
Gao, Yuan
Tobing, Landobasa Yosef Mario
Kiffer, Aurélien
Zhang, Dao Hua
Dang, Cuong
Demir, Hilmi Volkan
Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating
description Since optical gain was observed from colloidal quantum dots (CQDs), research on CQD lasing has been focused on the CQDs themselves as gain materials and their coupling with optical resonators. Combining the advantages of a CQD gain medium and optical microcavity in a laser device is desirable. Here, we show concentric circular Bragg gratings intimately incorporating CdSe/CdZnS/ZnS gradient shell CQDs. Because of the strong circularly symmetric optical confinement in two dimensions, the output beam CQD-based circular grating distributed feedback laser is found to be highly spatially coherent and azimuthally polarized with a donut-like cross section. We also observe the strong modification of the photoluminescence spectrum by the grating structures, which is associated with modification of optical density of states. This effect confirmed the high quality of the resonator that we fabricated and the spectral overlap between the optical transitions of the emitter and resonance of the cavity. Single mode lasing has been achieved under a quasi-continuous pumping regime, while the position of the lasing mode can be conveniently tuned via adjusting the thickness of the CQD layer. Moreover, a unidirectional output beam can be observed as a bright circular spot on a screen without any collimation optics, presenting a direct proof of its high spatial coherence.
author2 School of Electrical and Electronic Engineering
author_facet School of Electrical and Electronic Engineering
Gao, Yuan
Tobing, Landobasa Yosef Mario
Kiffer, Aurélien
Zhang, Dao Hua
Dang, Cuong
Demir, Hilmi Volkan
format Article
author Gao, Yuan
Tobing, Landobasa Yosef Mario
Kiffer, Aurélien
Zhang, Dao Hua
Dang, Cuong
Demir, Hilmi Volkan
author_sort Gao, Yuan
title Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating
title_short Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating
title_full Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating
title_fullStr Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating
title_full_unstemmed Azimuthally Polarized, Circular Colloidal Quantum Dot Laser Beam Enabled by a Concentric Grating
title_sort azimuthally polarized, circular colloidal quantum dot laser beam enabled by a concentric grating
publishDate 2017
url https://hdl.handle.net/10356/84891
http://hdl.handle.net/10220/43490
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