Broadband ultrafast nonlinear absorption and nonlinear refraction of layered molybdenum dichalcogenide semiconductors
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2014Access:
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Wang,Kangpeng K., Feng,Yanyan Y., Chang,Chunxia C., Zhan,Jingxin J., Wang,Chengwei C., Zhao,Quanzhong Q., Coleman,Jonathan N. J.N., Zhang,Long L., Blau,Werner Josef W.J., Wang,Jun J., Broadband ultrafast nonlinear absorption and nonlinear refraction of layered molybdenum dichalcogenide semiconductors, Nanoscale, 6, 18, 2014, 10530-10535Download Item:
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Abstract:
A series of layered molybdenum dichalcogenides,
i.e.
,MoX
2
(X
¼
S, Se
and Te), were prepared in cyclohexyl pyrrolidinone by a liquid-phase
exfoliation technique. The high quality of the two-dimensional
nanostructures was veri
fi
ed by transmission electron microscopy and
absorption spectroscopy. Open- and closed-aperture
Z
-scans were
employed to study the nonlinear absorption and nonlinear refraction
of the MoX
2
dispersions, respectively. All the three-layered nano-
structures exhibit prominent ultrafast saturable absorption (SA) for
both femtosecond (fs) and picosecond (ps) laser pulses over a broad
wavelength range from the visible to the near infrared. While the
dispersions treated with low-speed centrifugation (1500 rpm) have an
SA response, and the MoS
2
and MoSe
2
dispersions after higher speed
centrifugation (10 000 rpm) possess two-photon absorption for fs
pulses at 1030 nm, which is due to the signi
fi
cant reduction of the
average thickness of the nanosheets; hence, the broadening of band
gap. In addition, all dispersions show obvious nonlinear self-defo-
cusing for ps pulses at both 1064 nm and 532 nm, resulting from the
thermally-induced nonlinear refractive index. The versatile ultrafast
nonlinear properties imply a huge potential of the layered MoX
2
semiconductors in the development of nanophotonic devices, such as
mode-lockers, optical limiters, optical switches,
etc
Sponsor
Grant Number
Science Foundation Ireland (SFI)
2/IA/1306
Author's Homepage:
http://people.tcd.ie/colemajhttp://people.tcd.ie/wblau
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Nanoscale6
18
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Full text availableKeywords:
nanophotonic devicesDOI:
http://dx.doi.org/10.1039/c4nr02634aISSN:
20403364Licences: