Bound State in the Continuum in Nanoantenna-Coupled Slab Waveguide Enables Low-Threshold Quantum-Dot Lasing

Bound State in the Continuum in Nanoantenna-Coupled Slab Waveguide Enables Low-Threshold Quantum-Dot Lasing

Nano Letters

10.1021/acs.nanolett.1c03696

http://dx.doi.org/10.1021/acs.nanolett.1c03696

Mengfei Wu, Lu ding, Randy P. Sabatini, Laxmi Kishore Sagar, Golam Bappi, Ramón Paniagua-Domínguez, Edward H. Sargent, Arseniy I. Kuznetsov

15 November 2021

Wu, M., Ding, L., Sabatini, R. P., Sagar, L. K., Bappi, G., Paniagua-Domínguez, R., Sargent, E. H., & Kuznetsov, A. I. (2021). Bound State in the Continuum in Nanoantenna-Coupled Slab Waveguide Enables Low-Threshold Quantum-Dot Lasing. Nano Letters, 21(22), 9754–9760. https://doi.org/10.1021/acs.nanolett.1c03696

Colloidal quantum dots (CQDs) are a promising gain material for solution-processed, wavelength-tunable lasers, with potential application in displays, communications, and biomedical devices. In this work, we combine a CQD film with an array of nanoantennas, made of titanium dioxide cylinders, to achieve lasing via bound states in the continuum (BICs). Here, the BICs are symmetry-protected cavity modes with giant quality factors, arising from slab waveguide modes in the planar CQD film, coupled to the periodic nanoantenna array. We engineer the thickness of the CQD film and size of the nanoantennas to achieve a BIC with good spatial and spectral overlap with the CQDs, based on a 2nd-order TE-polarized waveguide mode. We obtain room-temperature lasing with a low threshold of approximately 11 kW/cm2 (peak intensity) under 5 ns-pulsed optical excitation. This work sheds light on the optical modes in solution-processed, distributed-feedback lasers, and highlights BICs as effective, versatile, surface-emitting lasing modes.

Publisher Copyright

This research / project is supported by the A*STAR - SERC Pharos programme
Grant Reference no. : 1527300025

This research / project is supported by the A*STAR - AME Programmatic Grant
Grant Reference no. : A18A7b0058

This research / project is supported by the National Research Foundation of Singapore - NRF Investigatorship
Grant Reference no. : NRF-NRFI2017-01

Overseas Funding:- Ontario Research FundResearch Excellence Program, the Natural Sciences and Engineering Research Council (NSERC) of Canada and Banting Postdoctoral Fellowship

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.nanolett.1c03696

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