Browsing by Author "Firstov, Sergei"

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Bismuth-doped fiber laser at 1.32 μm mode-locked by single-walled carbon nanotubes
(2018-09-03) Khegai, Aleksandr; Melkumov, Mikhail; Firstov, Sergei; Riumkin, Konstantin; Gladush, Yury; Alyshev, Sergey; Lobanov, Alexey; Khopin, Vladimir; Afanasiev, Fedor; Nasibulin, Albert G.; Dianov, Evgeny
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Bismuth-doped fiber is a promising active media for pulsed lasers operating in various spectral regions. In this paper, we report on a picosecond mode-locked laser at a wavelength of 1.32 μm, based on a phosphosilicate fiber doped with bismuth. Stable self-starting generation of dissipative solitons, using single-walled carbon nanotubes (SWCNT) as a saturable absorber, was achieved. Evolution of the pulsed regime, depending on pump power, and stability of the pulsing were investigated.
Real-time HCl gas detection at parts-per-billion level concentrations utilising a diode laser and a bismuth-doped fibre amplifier
(2021-05) Panu, Hildén; Timo, Rajamaki; Thomas, Fordell; Makkonen, Jarkko; Alyshev, Sergei; Kharakhordin, Alexandr; Firstov, Sergei
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
HCl measurements in a cleanroom environment are carried out using a cavity ring-down analyser in order to get an estimate of the HCl concentrations that can be expected to be present in semiconductor manufacturing. HCl is a reactive gas and the materials used for gas sampling and transportation have a significant effect on the measurement response time; hence, data on HCl adsorption to different materials is also provided. Finally, a light source operating at 1742 nm that can be used for HCl detection in a multi-gas analyser based on multipass photo-acoustic spectroscopy is presented. Preliminary results indicate that sub-ppb detection levels are achievable using this approach even for HCl.