Publications by authors named "Mohammed Al Araimi"

5 Publications

  • Page 1 of 1

Nonlinearity managed passively harmonic mode-locked Er-doped fiber laser based on carbon nanotube film.

Opt Lett 2021 Jun;46(11):2638-2641

We examine the implication of intracavity nonlinearity for harmonic mode locking (HML) by exploiting highly nonlinear fiber in a carbon nanotube film mode-locked Er-doped fiber laser. It is found that the reasonably large nonlinearity is of benefit to increase the extent of harmonic order while the excessive nonlinearity leads to some peculiar multi-pulse patterns such as noise-like pulse and soliton rain. Via appropriate nonlinearity management, nearly 4 GHz repetition rate pulses at the 91st harmonic with 936 fs pulse duration are delivered under the pump power of 280 mW. The pulse stability is evidenced by the super-mode suppression ratio of 35.6 dB. To the best of our knowledge, it is the highest repetition rate yet reported for a passively HML fiber laser based on a film-type physical saturable absorber. Furthermore, the laser exhibits steep pumping efficiency slope of ${\gt}{19}\;{\rm MHz/mW}$, which is also a record among all of the passively HML fiber lasers.
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http://dx.doi.org/10.1364/OL.425898DOI Listing
June 2021

Revealing the nature of morphological changes in carbon nanotube-polymer saturable absorber under high-power laser irradiation.

Sci Rep 2018 May 10;8(1):7491. Epub 2018 May 10.

Nanotechnology Research Group and Aston Institute of Photonic Technologies, Aston University, Birmingham, B4 7ET, UK.

Composites of single-walled carbon nanotubes (SWNTs) and water-soluble polymers (WSP) are the focus of significant worldwide research due to a number of applications in biotechnology and photonics, particularly for ultrashort pulse generation. Despite the unique possibility of constructing non-linear optical SWNT-WSP composites with controlled optical properties, their thermal degradation threshold and limit of operational power remain unexplored. In this study, we discover the nature of the SWNT-polyvinyl alcohol (PVA) film thermal degradation and evaluate the modification of the composite properties under continuous high-power ultrashort pulse laser operation. Using high-precision optical microscopy and micro-Raman spectroscopy, we have examined SWNT-PVA films before and after continuous laser radiation exposure (up to 40 hours) with a maximum optical fluence of 2.3 mJ·cm. We demonstrate that high-intensity laser radiation results in measurable changes in the composition and morphology of the SWNT-PVA film due to efficient heat transfer from SWNTs to the polymer matrix. The saturable absorber modification does not affect the laser operational performance. We anticipate our work to be a starting point for more sophisticated research aimed at the enhancement of SWNT-PVA films fabrication for their operation as reliable saturable absorbers in high-power ultrafast lasers.
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http://dx.doi.org/10.1038/s41598-018-24734-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5945804PMC
May 2018

Double-Wall Carbon Nanotube Hybrid Mode-Locker in Tm-doped Fibre Laser: A Novel Mechanism for Robust Bound-State Solitons Generation.

Sci Rep 2017 03 13;7:44314. Epub 2017 Mar 13.

Nanoscience Research Group and Aston Institute of Photonics Technologies Aston University, Aston triangle Birmingham, B4 7ET, UK.

The complex nonlinear dynamics of mode-locked fibre lasers, including a broad variety of dissipative structures and self-organization effects, have drawn significant research interest. Around the 2 μm band, conventional saturable absorbers (SAs) possess small modulation depth and slow relaxation time and, therefore, are incapable of ensuring complex inter-pulse dynamics and bound-state soliton generation. We present observation of multi-soliton complex generation in mode-locked thulium (Tm)-doped fibre laser, using double-wall carbon nanotubes (DWNT-SA) and nonlinear polarisation evolution (NPE). The rigid structure of DWNTs ensures high modulation depth (64%), fast relaxation (1.25 ps) and high thermal damage threshold. This enables formation of 560-fs soliton pulses; two-soliton bound-state with 560 fs pulse duration and 1.37 ps separation; and singlet+doublet soliton structures with 1.8 ps duration and 6 ps separation. Numerical simulations based on the vectorial nonlinear Schr¨odinger equation demonstrate a transition from single-pulse to two-soliton bound-states generation. The results imply that DWNTs are an excellent SA for the formation of steady single- and multi-soliton structures around 2 μm region, which could not be supported by single-wall carbon nanotubes (SWNTs). The combination of the potential bandwidth resource around 2 μm with the soliton molecule concept for encoding two bits of data per clock period opens exciting opportunities for data-carrying capacity enhancement.
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http://dx.doi.org/10.1038/srep44314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5347134PMC
March 2017

A dioxaborine cyanine dye as a photoluminescence probe for sensing carbon nanotubes.

Beilstein J Nanotechnol 2016 14;7:1991-1999. Epub 2016 Dec 14.

Engineering Department, Al Musanna College of Technology, Muladdah Musanna, P.O. Box 191, P.C. 314, Sultanate of Oman.

The unique properties of carbon nanotubes have made them the material of choice for many current and future industrial applications. As a consequence of the increasing development of nanotechnology, carbon nanotubes show potential threat to health and environment. Therefore, development of efficient method for detection of carbon nanotubes is required. In this work, we have studied the interaction of indopentamethinedioxaborine dye (DOB-719) and single-walled carbon nanotubes (SWNTs) using absorption and photoluminescence (PL) spectroscopy. In the mixture of the dye and the SWNTs we have revealed new optical features in the spectral range of the intrinsic excitation of the dye due to resonance energy transfer from DOB-719 to SWNTs. Specifically, we have observed an emergence of new PL peaks at the excitation wavelength of 735 nm and a redshift of the intrinsic PL peaks of SWNT emission (up to 40 nm) in the near-infrared range. The possible mechanism of the interaction between DOB-719 and SWNTs has been proposed. Thus, it can be concluded that DOB-719 dye has promising applications for designing efficient and tailorable optical probes for the detection of SWNTs.
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http://dx.doi.org/10.3762/bjnano.7.190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5238636PMC
December 2016

Isolator-free switchable uni- and bidirectional hybrid mode-locked erbium-doped fiber laser.

Opt Express 2016 Jul;24(14):15721-9

An Erbium-doped fibre ring laser hybrid mode-locked with single-wall carbon nanotubes (SWNT) and nonlinear polarisation evolution (NPE) without an optical isolator has been investigated for various cavity conditions. Precise control of the state of polarisation (SOP) in the cavity ensures different losses for counter-propagating optical fields. As the result, the laser operates in quasi-unidirectional regime in both clockwise (CW) and counter-clockwise (CCW) directions with the emission strengths difference of the directions of 22 dB. Furthermore, by adjusting the net birefringence in the cavity, the laser can operate in a bidirectional generation. In this case, a laser pumped with 75 mW power at 980 nm generates almost identical 790 and 570 fs soliton pulses with an average power of 1.17 and 1.11 mW. The operation stability and pulse quality of the soliton pulses in both unidirectional regimes are highly competitive with those generated in conventional ring fibre lasers with isolator in the cavity. Demonstrated bidirectional laser operation can find vital applications in gyroscopes or precision rotation sensing technologies.
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http://dx.doi.org/10.1364/OE.24.015721DOI Listing
July 2016
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