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Your search keyword '"Adamu, Abubakar I."' showing total 42 results
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42 results on '"Adamu, Abubakar I."'

1. Multi-wavelength high energy gas-filled fiber Raman laser spanning from 1.53 um to 2.4 um

Author

Adamu, Abubakar I., Wang, Yazhou, Habib, MD. Selim, Dasa, Manoj. K., Antonio-Lopez, J. E, Amezcua-Correa, Rodrigo, Bang, Ole, and Markos, Christos

Subjects
Physics - Optics
Abstract

In this work, we present a high pulse energy multi-wavelength Raman laser spanning from 1.53 um up to 2.4 um by employing the cascaded rotational stimulated Raman scattering (SRS) effect in a 5-m hydrogen (H2) -filled nested anti-resonant fiber (NARF), pumped by a linearly polarized Er/Yb fiber laser with a peak power of ~13 kW and pulse duration of ~7 ns in the C-band. The developed Raman laser has distinct lines at 1683 nm, 1868 nm, 2100 nm, and 2400 nm, with pulse energies as high as 18.25 uJ, 14.4 uJ, 14.1 uJ, and 8.2 uJ, respectively. We demonstrate how the energy in the Raman lines can be controlled by tuning the H2 pressure from 1 bar to 20 bar

Published
2020
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2. Noise and spectral stability of deep-UV gas-filled fiber-based supercontinuum sources driven by ultrafast mid-IR pulses

Author

Adamu, Abubakar I., Habib, Md. Selim, Lopez, J. Enrique Antonio, Jepsen, Peter Uhd, Amezcua-Correa, Rodrigo, Bang, Ole, and Markos, Christos

Subjects
Physics - Optics
Abstract

Deep-UV (DUV) supercontinuum (SC) sources based on gas-filled hollow-core fibers constitute perhaps the most viable solution towards ultrafast, compact, and tunable lasers in the UV spectral region. Noise and spectral stability of such broadband sources are key parameters that define their true potential and suitability towards real-world applications. In order to investigate the spectral stability and noise levels in these fiber-based DUV sources, we generate an SC spectrum that extends from 180 nm (through phase-matched dispersive waves - DWs) to 4 {\mu}m by pumping an argon-filled hollow-core anti-resonant fiber at a wavelength of 2.45 {\mu}m. We characterize the long-term stability of the source over several days and the pulse-to-pulse relative intensity (RIN) noise of the strongest DW at 275 nm. The results indicate no sign of spectral degradation over 110 hours, but the RIN of the DW pulses at 275 nm is found to be as high as 33.3%. Numerical simulations were carried out to investigate the spectral distribution of the RIN and the results confirm the experimental measurements and that the poor noise performance is due to the RIN of the pump laser, which was hitherto not considered in numerical modelling of these sources. The results presented herein provide an important step towards an understanding of the noise mechanism underlying such complex light-gas nonlinear interactions and demonstrate the need for pump laser stabilization.

Published
2019
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3. Deep-UV to mid-IR supercontinuum generation driven by mid-IR ultrashort pulses in a gas-filled fiber

Author

Adamu, Abubakar I., Habib, Md. Selim, Petersen, Christian R., Antonio-Lopez, J. Enrique, Zhou, Binbin, Schülzgen, Axel, Amezcua-Correa, Rodrigo, Bang, Ole, and Markos, Christos

Subjects
Physics - Optics
Abstract

Supercontinuum (SC) generation based on ultrashort pulse compression constitutes one of the most promising technologies towards an ultra-wide bandwidth, high-brightness and spatially coherent light sources for applications such as spectroscopy and microscopy. Here, multi-octave SC generation in a gas-filled hollow-core antiresonant fiber (HC-ARF) is reported spanning from 200 nm in the deep ultraviolet (DUV) to 4000 nm in the mid-infrared (mid-IR). A measured average output power of 5 mW was obtained by pumping at the center wavelength of the first anti-resonance transmission window (2460 nm) with ~100 fs pulses and an injected pulse energy of ~7-8 {\mu}J. The mechanism behind the extreme spectral broadening relies upon intense soliton-plasma nonlinear dynamics which leads to efficient soliton self-compression and phase-matched dispersive wave (DW) emission in the DUV region. The strongest DW is observed at 275 nm having an estimated pulse energy of 1.42 {\mu}J, corresponding to 28.4 % of the total output energy. Furthermore, the effect of changing the pump pulse energy and gas pressure on the nonlinear dynamics and their direct impact on SC generation was investigated. The current work paves a new way towards novel investigations of gas-based ultrafast nonlinear optics in the emerging mid-IR spectral regime.

Published
2018
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13. Ultraviolet to mid-infrared gas-filled anti-resonant hollow-core fiber lasers

Author

Wang, Yazhou, primary, Adamu, Abubakar I., additional, Habib, Md. Selim, additional, Dasa, Manoj K., additional, Petersen, Christian R., additional, Antonio-Lopez, J. Enrique, additional, Zhou, Binbin, additional, Jepsen, Peter Uhd ., additional, Schülzgen, Axel, additional, Bache, Morten, additional, Amezcua Correa, Rodrigo, additional, Bang, Ole, additional, and Markos, Christos, additional

Published
2021
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20. Comprehensive Performance Evaluation on Multiplication of Matrices using MPI

Author

Adamu Abubakar I, Oyku A, and Mehmet K | Amina M. Tako

Subjects
Message Passing Inteface, Matrix multiplication and Efficiency, Performance evaluation, Electrical Engineering
Abstract

In Matrix multiplication we refer to a concept that is used in technology applications such as digital image processing, digital signal processing and graph problem solving. Multiplication of huge matrices requires a lot of computing time as its complexity is O n3 . Because most engineering science applications require higher computational throughput with minimum time, many sequential and analogue algorithms are developed. In this paper, methods of matrix multiplication are elect, implemented, and analyzed. A performance analysis is evaluated, and some recommendations are given when using open MP and MPI methods of parallel of latitude computing. Adamu Abubakar I | Oyku A | Mehmet K | Amina M. Tako "Comprehensive Performance Evaluation on Multiplication of Matrices using MPI" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020, URL: https://www.ijtsrd.com/papers/ijtsrd30015.pdf

Published
2020
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35. Multi-wavelength high-energy gas-filled fiber Raman laser spanning from 1.53??µm to 2.4??µm

Author

Adamu, Abubakar I., Wang, Yazhou, Habib, Md. Selim, Dasa, Manoj. K., Antonio-Lopez, J. E., Amezcua-Correa, Rodrigo, Bang, Ole, and Markos, Christos

Abstract

In this work, we present a high-pulse-energy multi-wavelength Raman laser spanning from 1.53 µm up to 2.4 µm by employing the cascaded rotational stimulated Raman scattering effect in a 5 m hydrogen (H_2)-filled nested anti-resonant fiber, pumped by a linearly polarized Er/Yb fiber laser with a peak power of ∼13kW and pulse duration of ∼7ns in the C-band. The developed Raman laser has distinct lines at 1683 nm, 1868 nm, 2100 nm, and 2400 nm, with pulse energies as high as 18.25 µJ, 14.4 µJ, 14.1 µJ, and 8.2 µJ, respectively. We demonstrate how the energy in the Raman lines can be controlled by tuning the H_2 pressure from 1 bar to 20 bar.

Published
2021

42. High pulse energy and quantum efficiency mid-infrared gas Raman fiber laser targeting CO 2 absorption at 4.2  µm.

Author

Wang Y, Dasa MK, Adamu AI, Antonio-Lopez JE, Habib MS, Amezcua-Correa R, Bang O, and Markos C

Abstract

In this Letter, we demonstrate a high pulse energy and linearly polarized mid-infrared Raman fiber laser targeting the strongest absorption line of ${\rm CO}_2$CO 2 at $\sim{4.2}\;\unicode {x00B5} {\rm m}$∼4.2µm. This laser was generated from a hydrogen (${\rm H}_2$H 2 )-filled antiresonant hollow-core fiber, pumped by a custom-made 1532.8 nm Er-doped fiber laser delivering 6.9 ns pulses and 11.6 kW peak power. A quantum efficiency as high as 74% was achieved, to yield 17.6 µJ pulse energy at 4.22 µm. Less than 20 bar ${\rm H}_2$H 2 pressure was required to maximize the pulse energy since the transient Raman regime was efficiently suppressed by the long pump pulses.

Published
2020
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