Graphene oxide: preparation, functionalization, and electrochemical applications.

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.

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Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

Functional π-Gelators and Their Applications

and Applications of Fullerenes, Carbon Dots, Nanotubes, Graphene, Nanodiamonds, and Combined Superstructures Vasilios Georgakilas,† Jason A. Perman,‡ Jiri Tucek,‡ and Radek Zboril*,‡ †Material Science Department, University of Patras, 26504 Rio Patras, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University in Olomouc, 17 listopadu 1192/12, 771 46 Olomouc, Czech Republic

Broad family of carbon nanoallotropes: classification, chemistry, and applications of fullerenes, carbon dots, nanotubes, graphene, nanodiamonds, and combined superstructures.

This Review explains the concept of dissipative solitons and their application to high-energy mode-locked fibre laser cavities. Dynamics and effects such as dissipative soliton ‘explosions’ and ‘rain’ are summarized, and an outlook of the field is also provided.

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Dissipative solitons for mode-locked lasers

We report on an ytterbium-doped photonic-crystal-fiber–based chirped-pulse amplification system delivering 131?W average power 220?fs pulses at 1040?nm center wavelength in a diffraction-limited beam. The pulse repetition rate is 73?MHz, corresponding to a pulse energy of 1.8??J and a peak power as high as 8.2?MW.

131 W 220 fs fiber laser system.

We report on the generation of high-energy ultrashort pulses from a mode-locked Yb-doped large-mode-area fiber laser operating in the all-normal dispersion regime. The self-starting fiber laser emits 9 W of average output power at a pulse repetition rate of 9.7 MHz, corresponding to a pulse energy of 927 nJ. The laser produces positively chirped 8 ps output pulses, which are then compressed down to 711 fs. These compressed pulses exhibit megawatt-level peak powers. To our knowledge, this is the first time that a mode-locked fiber oscillator has generated femtosecond pulses with pulse energies approaching the microjoule level in combination with high average output power. Numerical simulations show excellent agreement with experimental results and reveal further scaling potential, which is discussed.

Approaching microjoule-level pulse energy with mode-locked femtosecond fiber lasers.

We report on the generation of self-similar pulses from an self-starting saturable absorber mirror (SAM) based environmentally stable fiber laser comprising only polarization maintaining (PM) fibers. Pulse energies of 1 nJ at a repetition rate of 17 MHz were obtained, which could be externally compressed to an autocorrelation width of 280 fs.

Self-starting self-similar all-polarization maintaining Yb-doped fiber laser

We report on a mode-locked high energy fiber laser operating in the dispersion compensation free regime. The sigma cavity is constructed with a saturable absorber mirror and short-length large-mode-area photonic crystal fiber. The laser generates positively-chirped pulses with an energy of 265 nJ at a repetition rate of 10.18 MHz in a stable and self-starting operation. The pulses are compressible down to 400 fs leading to a peak power of 500 kW. Numerical simulations accurately reflect the experimental results and reveal the mechanisms for self consistent intra-cavity pulse evolution. With this performance mode-locked fiber lasers can compete with state-of-the-art bulk femtosecond oscillators for the first time and pulse energy scaling beyond the µJ-level appears to be feasible.

High-energy femtosecond Yb-doped dispersion compensation free fiber laser

We report on ultrashort pulse generation from a passively mode-locked erbium fiber laser operating in the highly positive dispersion regime. Highly-chirped pulses with 5.3 ps duration and spectral bandwidth of 8.3 nm are generated. They are extra-cavity compressed down to 757 fs. Numerical simulations confirm the experimental results and show that these pulses could be interpreted as dissipative solitons.

Bülend Ortaç

Papers

131 W 220 fs fiber laser system.

Approaching microjoule-level pulse energy with mode-locked femtosecond fiber lasers.

Self-starting self-similar all-polarization maintaining Yb-doped fiber laser

High-energy femtosecond Yb-doped dispersion compensation free fiber laser

Dissipative solitons in a passively mode-locked Er-doped fiber with strong normal dispersion.