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
Abstract:
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.
License type:
Publisher Copyright
Funding Info:
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