biomedicine, [2,3] tribology, [4] photonics, [5] and electrocatalysis, [6] among others. Significant progress has been made recently in fabricating and functionalizing 2D nanosheets of transition metal dichalcogenides. [7] This progress has focused on the functionalization of mono-or few-layer nanosheets with lateral dimensions greater than 100 nm by combining chemical exfoliation, [8][9][10][11][12] micromechanical exfoliation, [13] or liquid exfoliation [14] with the reaction of functionalities. The formation and functionalization of smaller 2D nanoparticles or quantum dots, on the other hand, is still in its infancy.In what has been cited as the first direct evidence of covalent functionalization of a nanoscale transition metal dichalcogenide, Tuxen et al. produced MoS 2 monolayer nanoclusters in ultrahigh vacuum on a gold substrate and attached dibenzothiophene molecules to the clusters via controlled vapor exposure. [15,16] Beyond substrate-supported nanoclusters, the functionalization of nongraphene 2D nanoparticles suspended in solution was reported last year. Atkin et al. combined ultrasonication of WS 2 with microwave treatment in a citric acid-containing solution to produce monolayer WS 2 nanosheets ≈20-80 nm in diameter decorated with 2-5 nm carbon dots. [6] Jung et al. impinged BN flakes with super-heated nanoparticles then exposed them to water vapor to produce edge-hydroxylated BN quantum dots with 8 nm lateral size. [2] These techniques for fabricating and functionalizing 2D nanosheets and smaller nanoparticles are relatively slow (in some cases requiring several days), often require dangerous chemicals and elevated temperatures, and their demonstration has been material specific. In the case of functionalized 2D nanoparticles other than graphene, such as functionalized MoS 2 , WS 2 , and BN quantum dots, potentially exciting multifunctional optical properties have not been realized. The ability to produce a variety of hybrid 2D nanoparticles that possess the optical properties of both the host 2D material and functional groups would be extremely valuable for many of the aforementioned applications.We introduce a rapid femtosecond laser technique that simultaneously reduces the dimensions of flakes of 2D materials to a few nanometers and dissociates solvent molecules to bond with the edges of the freshly cleaved 2D sheets, in order to produce functionalized nanoparticles of 2D materials. Etha nol, a common and inexpensive solvent, is used to facilitate functionalization A general, rapid technique is introduced to simultaneously fabricate and functionalize nanoparticles of 2D materials. A femtosecond laser is used to irradiate flakes of 2D materials in an ethanol-containing solvent. The highly energetic laser pulses exfoliate and cleave the flakes into nanosheets with diameters of ≈3 nm and simultaneously dissociate the solvent molecules. The dissociated carbon and oxygen atoms bond with the freshly cleaved 2D nanoparticles to satisfy edge sites, resulting in the formation of hybrid 2D nanoparticles...

We report on the first demonstration of an optical waveguide amplifier in phospho-tellurite glass providing net gain at 1.5 μm. The device was fabricated using a high repetition rate femtosecond laser and exhibited internal gain across 100-nm bandwidth covering the entire C + L telecom bands.

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Localized Surface Plasmon Resonance (LSPR) sensors have potential applications in essential and important areas such as bio-sensor technology, especially in medical applications and gas sensors in environmental monitoring applications. Figure of Merit (FOM) and Sensitivity (S) measurements are two ways to assess the performance of an LSPR sensor. However, LSPR sensors suffer low FOM compared to the conventional Surface Plasmon Resonance (SPR) sensor due to high losses resulting from radiative damping of LSPs waves. Different methodologies have been utilized to enhance the performance of LSPR sensors, including various geometrical and material parameters, plasmonic wave coupling from different structures, and integration of noble metals with graphene, which is the focus of this report. Recent studies of metal-graphene hybrid plasmonic systems have shown its capability of promoting the performance of the LSPR sensor to a level that enhances its chance for commercialization. In this review, fundamental physics, the operation principle, and performance assessment of the LSPR sensor are presented followed by a discussion of plasmonic materials and a summary of methods used to optimize the sensor’s performance. A focused review on metal-graphene hybrid nanostructure and a discussion of its role in promoting the performance of the LSPR sensor follow.

Graphene and its functionalized derivatives are unique and multifaceted novel materials with a wide range of applications in chemistry, healthcare, and optoelectronic engineering. 3D graphene materials exhibit several advantages over 2D (monolayer) graphene for a variety of devices applications. Here a novel and effective room temperature technique is introduced to convert an aqueous graphene oxide solution into a reduced graphene oxide gel with tunable physical and chemical properties comparable to a monolayer graphene sheet, without the need for any additives or chemical agents. The femtogel is synthesized by exposing an ultrahigh concentration graphene oxide solution with single‐layer flakes to high intensity femtosecond laser pulses. The femtosecond laser beam is focused on the air/aqueous solution interface to enhance the vaporization of functional groups and water, enabling femtogel formation. By controlling the pulsed laser intensity, beam focal parameters, and pulse duration, it is possible to produce several milliliters of femtogel in as little as 8 min. Through initial optimization of the irradiation parameters, a thin film is produced from a femtogel that demonstrates a surface roughness less than 6 nm, and more than 95% reduction in OH absorbance, as compared to a thin film produced from the unexposed graphene oxide solution.

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