Polymer composites are one of the most attractive near‐term means to exploit the unique properties of carbon nanotubes and graphene. This is particularly true for composites aimed at electronics and ...photonics, where a number of promising applications have already been demonstrated. One such example is nanotube‐based saturable absorbers. These can be used as all‐optical switches, optical amplifier noise suppressors, or mode‐lockers to generate ultrashort laser pulses. Here, we review various aspects of fabrication, characterization, device implementation and operation of nanotube‐polymer composites to be used in photonic applications. We also summarize recent results on graphene‐based saturable absorbers for ultrafast lasers.
Carbon nanotube–polymer composites offer a flexible and cheap wet‐chemistry‐based route to photonic device fabrication. These are prepared by dispersing nanotubes, which are ideal saturable absorbers, in solvents compatible with the target host polymer. These composites can then be used to generate ultrashort laser pulses by passive mode‐locking in fiber‐laser cavities.
Graphene, a two-dimensional hexagonal honeycomb carbon structure, is widely used in membrane technologies thanks to its unique optical, electrical, mechanical, thermal, chemical and photoelectric ...properties. The light weight, mechanical strength, anti-bacterial effect, and pollution-adsorption properties of graphene membranes are valuable in water treatment studies. Incorporation of nanoparticles like carbon nanotubes (CNTs) and metal oxide into the graphene filtering nanocomposite membrane structure can provide an improved photocatalysis process in a water treatment system. With the rapid development of graphene nanocomposites and graphene nanocomposite membrane-based acoustically supported filtering systems, including CNTs and visible-light active metal oxide photocatalyst, it is necessary to develop the researches of sustainable and environmentally friendly applications that can lead to new and groundbreaking water treatment systems. In this review, characteristic properties of graphene and graphene nanocomposites are examined, various methods for the synthesis and dispersion processes of graphene, CNTs, metal oxide and polymer nanocomposites and membrane fabrication and characterization techniques are discussed in details with using literature reports and our laboratory experimental results. Recent membrane developments in water treatment applications and graphene-based membranes are reviewed, and the current challenges and future prospects of membrane technology are discussed.
We report experimental observation of new tightly and loosely bound state vector solitons with locked and precessing states of polarization in a carbon nanotube mode locked fiber laser in the ...anomalous dispersion regime.
Carbon nanotube polycarbonate composites with controlled nanotube‐bundle size are prepared by dispersion with conjugated polymers followed by blending with polycarbonate. The composite has uniform ...sub‐micrometer nanotube bundles in high concentration, shows strong nonlinear optical absorption, and generates 193 fs pulses when used as passive mode‐locker in a fiber laser.
Semiconductor quantum dots of the A
B
group and organic semiconductors have been widely studied and applied in optoelectronics. This study aims to combine CdTe quantum dots and perylene-based dye ...molecules into advanced nanostructure system targeting to improve their functional properties. In such systems, new electronic states, a mixture of Wannier-Mott excitons with charge-transfer excitons, have appeared at the interface of CdTe quantum dots and the perylene dye. The nature of such new states has been analyzed by absorption and photoluminescence spectroscopy with picosecond time resolution. Furthermore, aggregation of perylene dye on the CdTe has been elucidated, and contribution of Förster resonant energy transfer has been observed between aggregated forms of the dye and CdTe quantum dots in the hybrid CdTe-perylene nanostructures. The studied nanostructures have strongly quenched emission of quantum dots enabling potential application of such systems in dissociative sensing.
Ultrafast fiber sources having short pulses, broad bandwidth, high energy, and low amplitude fluctuations have widespread applications. Stretched-pulse fiber lasers, incorporating segments of normal ...and anomalous dispersion fibers, are a preferred means to generate such pulses. We realize a stretched-pulse fiber laser based on a nanotube saturable absorber, with 113 fs pulses, 33.5 nm spectral width and ˜0.07% amplitude fluctuation, outperforming current nanotube-based designs.
A free-standing film made of a single-wall carbon nanotube (SWCNT)–polyvinylalchol (PVA) composite material was fabricated by pretreatment of SWCNTs with ultrasonication in water with the aid of a ...surfactant that promotes unbundling of aggregated SWNCTs. Characterizations using optical absorption spectroscopy, optical microscopy, and micro-Raman spectroscopy revealed that the film has an optical absorption at approximately 1.5 μm, suitable for the occurrence of saturable absorption (a promising nonlinear optical effect) in optical telecommunication wavelengths, and that SWCNTs in the film are dispersed uniformly with a low scattering loss. The saturable absorption properties of the film at 1.56 μm measured using the Z-scan method was basically similar to those of the SWCNTs deposited on quartz glass, indicating that the free-standing SWCNT–PVA film is as promising as the SWCNT film deposited directly on a substrate.
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