Showing papers by "Aleksandra Krajewska published in 2013"
TL;DR: This is the shortest reported pulse duration achieved from a Tm-doped laser mode-locked by graphene saturable absorber and such cost-effective and stable fiber lasers might be considered as sources for mid-infrared spectroscopy and remote sensing.
Abstract: We report an all-fiber Tm-doped fiber laser mode-locked by graphene saturable absorber. The laser emits 1.2 ps pulses at 1884 nm center wavelength with 4 nm of bandwidth and 20.5 MHz mode spacing. The graphene layers were grown on copper foils by chemical vapor deposition (CVD) and transferred onto the fiber connector end. Up to date this is the shortest reported pulse duration achieved from a Tm-doped laser mode-locked by graphene saturable absorber. Such cost-effective and stable fiber lasers might be considered as sources for mid-infrared spectroscopy and remote sensing.
113 citations
TL;DR: In this article, the electrical characterization and Raman spectroscopy of chemical vapor deposition copper-grown graphene transferred onto a Si/SiO2 substrate by high-speed (1 mm/s) electrochemical delamination were reported.
Abstract: We report on the electrical characterization and Raman spectroscopy of chemical vapor deposition copper-grown graphene transferred onto a Si/SiO2 substrate by high-speed (1 mm/s) electrochemical delamination. We determine graphene’s sheet resistance, carrier mobility, and concentration as well as its physical quality as a function of the electolyte concentration. Graphene’s electrical properties are investigated with standard Hall measurements in van der Pauw geometry and a contactless method that employs a single-post dielectric resonator operating at microwave frequencies. These properties are related to the widely used copper etching technique. The results prove that the high-speed electrochemical delamination provides good-quality graphene within a short time scale.
77 citations
TL;DR: The reported experiment unambiguously confirms one of the biggest advantage of the carbon nanomaterial (in this case graphene) SAs over semiconductor saturable absorption mirrors (SESAM), which is broadband operation range, allowing to mode-lock two lasers spectrally separated by almost 400 nm.
Abstract: We present for the first time to the best of our knowledge an all-fiber thulium (Tm) and erbium (Er) doped fiber laser simultaneously mode-locked by a common graphene saturable absorber. The laser consists of two ring resonators combined with a common saturable absorber (SA). The generated optical solitons have a full width at half maximum (FWHM) of 3.9 nm and 4.2 nm for Tm- and Er-doped laser, respectively. The used graphene layers were grown on copper foils by chemical vapor deposition (CVD) and transferred onto the fiber connector end. Broadband and flat absorption spectrum of used SA supports mode-locked operation at 1565 nm and 1944 nm. The repetition frequency of the resonator with Er-doped fiber was 20.19 MHz while the Tm-doped resonator was around 1 m longer and resulted with repetition rate of 18.43 MHz. The reported experiment unambiguously confirms one of the biggest advantage of the carbon nanomaterial (in this case graphene) SAs over semiconductor saturable absorption mirrors (SESAM), which is broadband operation range, allowing to mode-lock two lasers spectrally separated by almost 400 nm.
63 citations