Type

Journal Article

Authors

Jonathan Nesbit Coleman
Jonathan Coleman
Werner Blau

Subjects

Physics

Topics
refractive index near infrared two dimensional nanophotonic devices broadband absorption optical switches absorption spectroscopy two photon absorption

Broadband ultrafast nonlinear absorption and nonlinear refraction of layered molybdenum dichalcogenide semiconductors (2014)

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
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Full list of authors on original publication

Jonathan Nesbit Coleman, Jonathan Coleman, Werner Blau

Experts in our system

1
Jonathan Coleman
Trinity College Dublin
Total Publications: 217
 
2
Werner Blau
Trinity College Dublin
Total Publications: 109