Terms Of Nonlinear Optical Properties Research Articles

Computational exploration of the structure-photophysical property relationship of 2,6-dicyanoaniline derivatives for optoelectronic applications

Design and development of 2,6-Dicyanoaniline based multifunctional organic molecules with an acceptor-donor-acceptor (A-D-A) framework is gaining momentum in recent years. However, identifying the suitable donor, acceptor and π-linkers remains challenging and necessitates a thorough understanding of the structure-property relationship. In this context, to enhance their properties, two experimentally reported dicyanoaniline (DCA) derivatives are subjected to structural modifications using four electron-releasing groups: OMe, NH2, NHMe, and NMe2, employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. Our findings reveal that all the designed molecules exhibit higher reactivity compared to the reference molecules, with NMe2 showing the most promising attributes, including a lower HOMO-LUMO gap. Percentage contribution analysis reveals that the strength of electron releasing groups significantly alter the stabilization of HOMO. Absorption and emission spectra are obtained from TD-DFT calculations in dimethyl formamide solvent. Moreover, calculations are performed to explore the Nonlinear Optical (NLO) performance of the designed molecules, indicating that all the designed molecules outperform the reference molecules in terms of NLO properties. In summary, this study offers valuable guidance for the development of efficient 2,6-Dicyanoaniline derivatives with great potential for optoelectronic and NLO applications.

Impact of photoinduced energy transfer and LSPR of Au and Ag nanoparticles on nonlinear optical response of methyl orange

In order to realize effective optical limiting (OL), it is necessary to utilize materials that exhibit distinct traits, such as a large and rapid nonlinear optical (NLO) response, high photothermal stability, and cost-effectiveness. In this work, the NLO properties of methyl orange (MO), a popular pH indicator, a potential nonlinear material, and an azo dye of great industrial importance are modulated by forming nanohybrids with Ag and Au nanoparticles. The NLO properties of the samples were investigated via the Z-scan technique using 7 ns laser pulses at a wavelength of 532 nm. A huge enhancement is observed in the nonlinear absorption (NLA) and OL performance MO-Ag and MO-Au nanohybrid compared to its constituent compounds, and it is attributable to photoinduced energy transfer between MO and metal NPs as well as the local field effect of NPs. The mechanisms responsible for the NLA and OL activity are primarily Excited State Absorption (ESA) with contributions from a weak Two-Photon Absorption (TPA). Notably, the nanohybrid system incorporating Au NPs outperforms the one with Ag NPs in terms of nonlinear optical properties under 532 nm excitation, primarily due to the better resonant energy transfer of Au compared to the Ag nanoparticle and intense local field effects of Au on exciting at 532 nm due to resonant absorption. The Closed Aperture (CA) Z-scan measurements were employed to investigate the nonlinear refraction property of the compounds, and both the pristine MO and its nanohybrid exhibited negative nonlinear refraction. These findings indicate that forming nanohybrids is an efficient way to modify the NLO response of MO. It also suggests MO has the potential for a diverse array of nonlinear optical applications, including but not limited to optical limiting.

Pure and Yb-Doped LaxYySc4-x-y(BO3)4 Crystals: A Review of Recent Advances

This paper reviews the progress in developing the LaxYySc4-x-y(BO3)4-LYSB and Yb-doped LaxYySc4-x-y(BO3)4-LYSB:Yb huntite-type crystals grown by the Czochralski method as new candidates for the next generation of nonlinear optical (NLO) and/or laser crystals. Considering the incongruent melting of these crystals, the initial compositions of the melt and the pulling and rotation rates were optimized. Additionally, a special thermal setup was engineered to grow LYSB-type crystals by the Czochralski crystal growth method. The chemical compositions of the LYSB and LYSB:Yb grown crystals were found to be La0.78Y0.32Sc2.90(BO3)4 and La0.78Y0.32Yb0.04Sc2.86(BO3)4, respectively. Therefore, for the LYSB:Yb crystal, the doping concentration of Yb3+ ions was considered to be 4 at.% with respect to the nonstoichiometric (La1-xYx)1.25Sc2.75(BO3)4 undoped compounds, i.e., LYSB:Yb (4 at.%). In terms of NLO properties, the obtained results demonstrate that LYSB and LYSB:Yb (4 at.%) crystals possess remarkable properties specific to huntite-type crystals. The main advantage of these crystals consists in the fact that they may be obtained with large dimensions and excellent optical quality by the Czochralski method, which recommends them as a new class of highly efficient crystals for different NLO applications, including second harmonic generation (SHG) of high-power or high-energy laser beams. The laser performances of the LYSB:Yb (4 at.%) crystal prove its favorable intrinsic properties to generate laser emissions in the 1 µm range with high efficiency. The efficient laser emission at ~1028 nm together with good NLO characteristics to convert its own emission into emission at ~514 nm via SHG make the LYSB:Yb (4 at.%) crystal a very promising active medium to be used in self-frequency doubling configuration.

Two‐Photon Absorption Enhancement by the Inclusion of a Tropone Ring in Distorted Nanographene Ribbons

A new family of distorted ribbon-shaped nanographenes was designed, synthesized, and their optical and electrochemical properties were evaluated, pointing out an unprecedented correlation between their structural characteristics and the two-photon absorption (TPA) responses and electrochemical band gaps. Three nanographene ribbons have been prepared: a seven-membered-ring-containing nanographene presenting a tropone moiety at the edge, its full-carbon analogue, and a purely hexagonal one. We have found that the TPA cross-sections and the electrochemical band gaps of the seven-membered-ring-containing compounds are higher and lower, respectively, than those of the fully hexagonal polycyclic aromatic hydrocarbon (PAH). Interestingly, the inclusion of additional curvature has a positive effect in terms of non-linear optical properties of those ribbons.

Graphene-Coated Nanowire Waveguides and Their Applications.

In recent years, graphene-coated nanowires (GCNWs) have attracted considerable research interest due to the unprecedented optical properties of graphene in terahertz (THz) and mid-infrared bands. Graphene plasmons in GCNWs have become an attractive platform for nanoscale applications in subwavelength waveguides, polarizers, modulators, nonlinear devices, etc. Here, we provide a comprehensive overview of the surface conductivity of graphene, GCNW-based plasmon waveguides, and applications of GCNWs in optical devices, nonlinear optics, and other intriguing fields. In terms of nonlinear optical properties, the focus is on saturable absorption. We also discuss some limitations of the GCNWs. It is believed that the research of GCNWs in the field of nanophotonics will continue to deepen, thus laying a solid foundation for its practical application.

2D Layered Materials: Synthesis, Nonlinear Optical Properties, and Device Applications

AbstractIn recent years, 2D layered materials, including graphene, topological insulators, transition metal dichalcogenides, black phosphorus, MXenes, graphitic carbon nitride, and metal‐organic frameworks, have attracted considerable interest due to their potential applications in the fields of physics, chemistry, biology, and energy. Their rise in the field of nonlinear photonics began around 2009 and has become an important research direction. Here, the synthesis techniques, nonlinear optical properties, integration strategies, and device applications of layered materials are reviewed. In terms of nonlinear optical properties, the focus is on saturable absorption and Kerr nonlinearity. On this basis, their applications in various pulsed lasers, including fiber lasers, solid‐state lasers, waveguide lasers, and related nonlinear optical phenomenon, are summarized. In addition, novel optical devices using layered materials, such as optical modulators, optical polarizers, optical switchers, and even all‐optical device, are also involved. It is believed that the development of 2D layered materials in the field of photonics will continue to deepen, thus laying a good foundation for its practical application.