Imperial College London
Alternate

ProfessorRupertOulton

Faculty of Natural Sciences, Department of Physics

Professor of Nanophotonics
 
 
 
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Contact

 

+44 (0)20 7594 7576r.oulton

 
 
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Location

 

914Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Ren:2022:rs.3.rs-2312053/v1,
author = {Ren, T and Wang, J and Kumar, A and Han, K and Kang, Y and Zhang, G and Wang, Z and Oulton, R and Eda, G and Gong, X},
doi = {rs.3.rs-2312053/v1},
title = {Optical gain spectrum and confinement factor of a monolayer semiconductor in an ultrahigh quality cavity},
url = {http://dx.doi.org/10.21203/rs.3.rs-2312053/v1},
year = {2022}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - <jats:title>Abstract</jats:title>        <jats:p>Two-dimensional (2D) semiconductors have attracted great attention as a novel class of gain materials for low-threshold on-chip coherent light sources. Due to their atomically thin scale, these materials exhibit distinct gain characteristics and associated emitter-to-cavity coupling when integrated into a cavity. Despite several experimental reports on lasing, the underlying gain mechanism of 2D materials remains elusive due to a lack of key information, including modal gain and confinement factor. Here, we demonstrate a novel approach to directly determine the absorption coefficient of monolayer WS<jats:sub>2</jats:sub> by characterizing the whispering gallery modes in a van der Waals microdisk cavity. By exploiting the cavity’s high intrinsic quality factor of 2.5×10<jats:sup>4</jats:sup>, the absorption coefficient spectrum is experimentally resolved with unprecedented accuracy. We show that the excitonic gain signal and confinement factor can be assessed by analyzing the quality factors near the exciton resonance. The excitonic gain reduces the WS<jats:sub>2</jats:sub> absorption coefficient by 2×10<jats:sup>4</jats:sup> cm<jats:sup>− 1</jats:sup> at room temperature, indicating a local population inversion described in the excitonic two-band model. These results are essential for unveiling the gain mechanism in emergent low-threshold 2D-semiconductor-based laser devices.</jats:p>
AU  - Ren,T
AU  - Wang,J
AU  - Kumar,A
AU  - Han,K
AU  - Kang,Y
AU  - Zhang,G
AU  - Wang,Z
AU  - Oulton,R
AU  - Eda,G
AU  - Gong,X
DO  - rs.3.rs-2312053/v1
PY  - 2022///
TI  - Optical gain spectrum and confinement factor of a monolayer semiconductor in an ultrahigh quality cavity
UR  - http://dx.doi.org/10.21203/rs.3.rs-2312053/v1
ER  -
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