March 2021
Spotlight Summary by Andrey Kuzmin
Ultrafast 3.5 µm fiber laser
Ultrafast mid-infrared (mid-IR) laser sources have drawn attention due to irreplaceable applications in molecular spectroscopy, mid-IR non-linear conversion processes and bio-diagnostics. Limited availability of gain materials in the mid-IR region for passively mode-locked laser sources, and high cost of optical parametric oscillators and amplifiers used for traditional mid-IR laser sources, push the investigators to apply new technologies and innovations in laser design.
The authors of this publication in Optics Letters have designed the first mode-locked fiber laser to operate in the femtosecond regime well beyond 3 μm. The design is based on laser diode pumped erbium-doped zirconium fluoride fiber and non-linear polarization rotation technique. In contrast to the well-known way of direct pumping of the upper laser level, the authors have used a double-wavelength pumping scheme to decrease population build-up in a metastable "virtual ground state." This design enabled an increase in efficiency of laser emission almost three times and to produce 3.5 μm wavelength pulses with minimum duration of 580 fs at a repetition rate of 68 MHz. The pulse energy was 3.2 nJ, corresponding to a peak power of 5.5 kW.
Hopefully this novel design will open new opportunities for a diverse range of optical mid-IR applications.
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The authors of this publication in Optics Letters have designed the first mode-locked fiber laser to operate in the femtosecond regime well beyond 3 μm. The design is based on laser diode pumped erbium-doped zirconium fluoride fiber and non-linear polarization rotation technique. In contrast to the well-known way of direct pumping of the upper laser level, the authors have used a double-wavelength pumping scheme to decrease population build-up in a metastable "virtual ground state." This design enabled an increase in efficiency of laser emission almost three times and to produce 3.5 μm wavelength pulses with minimum duration of 580 fs at a repetition rate of 68 MHz. The pulse energy was 3.2 nJ, corresponding to a peak power of 5.5 kW.
Hopefully this novel design will open new opportunities for a diverse range of optical mid-IR applications.
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Article Information
Ultrafast 3.5 µm fiber laser
Nathaniel Bawden, Ori Henderson-Sapir, Stuart D. Jackson, and David J. Ottaway
Opt. Lett. 46(7) 1636-1639 (2021) View: Abstract | HTML | PDF