Exceptional Nonlinear Optical Properties Research Articles

Predesigned perovskite crystal waveguides for room-temperature exciton-polariton condensation and edge lasing.

Perovskite crystals-with their exceptional nonlinear optical properties, lasing and waveguiding capabilities-offer a promising platform for integrated photonic circuitry within the strong-coupling regime at room temperature. Here we demonstrate a versatile template-assisted method to efficiently fabricate large-scale waveguiding perovskite crystals of arbitrarily predefined geometry such as microwires, couplers and splitters. We non-resonantly stimulate a condensate of waveguided exciton-polaritons resulting in bright polariton lasing from the transverse interfaces and corners of our perovskite microstructures. Large blueshifts with excitation power and high mutual coherence between the different edge and corner lasing signals are detected in the far-field photoluminescence, implying that a spatially extended condensates of coherent polaritons has formed. The condensate polaritons are found to propagate over long distances in the wires from the excitation spot and can couple to neighbouring wires through large air gaps, making our platform promising for integrated polaritonic circuitry and on-chip optical devices with strong nonlinearities.

A novel Cadmium metal-organic framework with exceptional nonlinear optical properties: Unveiling anisotropic charge transport and optical limiting behavior

A novel non-centrosymmetric Cadmium Metal-Organic Framework (Cd-MOF) crystal with chemical formula CdC8N8H14O2S4 was synthesized and characterized. The band structure and optical limiting properties of the Cd-MOF were investigated using Band structure calculations and Optical limiting studies. The band structure analysis showed that the crystal displayed a larger, highly dispersive band, highlighting significant anisotropic n-channel charge carrier mobility. The optical limiting study demonstrated that the Cd-MOF exhibited Reverse Saturable Absorption (RSA) behaviour with an optical limiting threshold value of 1094 kW/cm2. The NLO behaviour of the Cd-MOF provides a promising potential for its application in NLO devices.

High-Order Harmonics Generation in MoS2 Transition Metal Dichalcogenides: Effect of Nickel and Carbon Nanotube Dopants.

The transition metal dichalcogenides have instigated a lot of interest as harmonic generators due to their exceptional nonlinear optical properties. Here, the molybdenum disulfide (MoS2) molecular structures with dopants being in a plasma state are used to demonstrate the generation of intense high-order harmonics. The MoS2 nanoflakes and nickel-doped MoS2 nanoflakes produced stronger harmonics with higher cut-offs compared with Mo bulk and MoS2 bulk. Conversely, the MoS2 with nickel nanoparticles and carbon nanotubes (MoS2-NiCNT) produced weaker coherent XUV emissions than other materials, which is attributed to the influence of phase mismatch. The influence of heating and driving pulse intensities on the harmonic yield and cut-off energies are investigated in MoS2 molecular structures. The enhanced coherent extreme ultraviolet emission at ~32 nm (38 eV) due to the 4p-4d resonant transitions is obtained from all aforementioned molecular structures, except for MoS2-NiCNT.

Recent advances in thulium-doped fiber lasers based on saturable absorber materials at 2000 nm

Thulium-doped fiber laser (TDFL) devices are a promising laser source technology for applications in the wavelength of 2000 nm, such as spectroscopy, sensing, medical, among many others. Several pulse regimes employing different approaches have been constantly demonstrated in the scientific literature. Particularly, the development of new saturable absorber (SA) materials with exceptional nonlinear optical properties has become an efficient methodology for generating short pulses in fiber laser cavities at 2000 nm. Looking for clarifying the current state of the art of TDFL technology at 2000 nm, we review in this paper the main achievements of TDFLs in the last five years (2022–2018) based on SA materials. Nonlinear optical properties of these materials, experimental setup arrangements, as well as new avenues are addressed in this review for the advancements in source laser technologies operating at 2000 nm.

Additive‐Triggered Polar Polymorph Formation: β‐Sc(IO 3 ) 3 , a Promising Next‐Generation Mid‐Infrared Nonlinear Optical Material

Noncentrosymmetric (NCS) solids have attracted interest for their potential in ferroelectric, piezoelectric, and nonlinear optical (NLO) devices, but their synthesis remains a major challenge. In this study, the additive Li2CO3 triggers formation of an NCS precursor at an early nucleation stage, and plays a crucial role in the successful polymorphism transformation. The resultant metastable β-Sc(IO3)3 is a promising mid-infrared NLO crystal, with the strongest second-harmonic generation responses (2.2 × KTiOPO4 @ 2100 nm, 16 × KH2PO4 @ 1064 nm) and the largest optical bandgap (4.52 eV) for a rare-earth iodate, as well as sufficient birefringence (Δn = 0.219 @ 546 nm) for type I phase-matching, and wide optical transparency, which are induced by optimal alignment of the iodate anions. This study reveals the key role of additives in the growth of polar NCS solids, a discovery with implications for the strategic design of new NCS polymorphism materials with exceptional NLO properties.

Additive-Triggered Polar Polymorph Formation: β-Sc(IO3 )3 , a Promising Next-Generation Mid-Infrared Nonlinear Optical Material.

Noncentrosymmetric (NCS) solids have attracted interest for their potential in ferroelectric, piezoelectric, and nonlinear optical (NLO) devices, but their synthesis remains a major challenge. In this study, the additive Li2 CO3 triggers formation of an NCS precursor at an early nucleation stage, and plays a crucial role in the successful polymorphism transformation. The resultant metastable β-Sc(IO3 )3 is a promising mid-infrared NLO crystal, with the strongest second-harmonic generation responses (2.2×KTiOPO4 @ 2100 nm, 16×KH2 PO4 @ 1064 nm) and the largest optical band gap (4.52 eV) for a rare-earth iodate, as well as sufficient birefringence (Δn=0.219 @ 546 nm) for type I phase-matching, and wide optical transparency, which are induced by optimal alignment of the iodate anions. This study reveals the key role of additives in the growth of polar NCS solids, a discovery with implications for the strategic design of new NCS polymorphism materials with exceptional NLO properties.

Recent progress in optical dark pulses generation based on saturable absorber materials

Dark pulses are optical structures with fascinating fundamental physics and have a great wealth of optical properties yet to be better explored. Since the earliest demonstration of a dark pulse, its generation was very limited, depending on specific experimental setups for its observation. However, the development of new saturable absorber (SA) materials with exceptional nonlinear optical properties have provided an efficient method for generating dark pulses in fiber laser cavities. In this perspective, this paper presents a review focused on recent progress in optical dark pulses generation based on SA materials. Specifically, materials such as graphene and its oxides, carbon nanotubes, transition metal dichalcogenides, transition metal trichalcogenides, metalloid trichalcogenides, black phosphorus, indium tin oxide, ferroferric oxide, ferromagnetic insulator, graphite oxide, and even glycerin and thulium-doped fiber will be approached here as promising candidates for SA materials. Nonlinear optical properties of these materials, configurations of experimental setups, as well as future perspectives are addressed in this review for the advancements in photonics technologies.

Terahertz Nonlinear Optics of Graphene: From Saturable Absorption to High‐Harmonics Generation

AbstractGraphene has long been predicted to show exceptional nonlinear optical properties, especially in the technologically important terahertz (THz) frequency range. Recent experiments have shown that this atomically thin material indeed exhibits possibly the largest nonlinear coefficients of any material known to date, paving the way for practical graphene‐based applications in ultrafast (opto‐)electronics operating at THz rates. Here the advances in the booming field of nonlinear THz optics of graphene are reported, and the state‐of‐the‐art understanding of the nature of the nonlinear interaction of graphene with the THz fields based on the thermodynamic model of electron transport in graphene is described. A comparison between different mechanisms of nonlinear interaction of graphene with light fields in THz, infrared, and visible frequency ranges is also provided. Finally, the perspectives for the expected technological applications of graphene based on its extraordinary THz nonlinear properties are summarized. This report covers the evolution of the field of THz nonlinear optics of graphene from the very pioneering to the state‐of‐the‐art works. It also serves as a concise overview of the current understanding of THz nonlinear optics of graphene and as a compact reference for researchers entering the field, as well as for the technology developers.

Performance enhancement of passively Q-switched Nd:YVO4 laser using graphene–molybdenum disulphide heterojunction as a saturable absorber

Two-dimensional (2D) materials, such as graphene and molybdenum disulphide (MoS2), are attractive for pulse laser applications owing to their exceptional nonlinear optical properties. In this paper, we fabricated three different saturable absorbers (SAs) based on plasma-enhanced chemical vapour deposition (PE-CVD) and liquid-phase exfoliation. The transmissivities of fabricated graphene, MoS2 and graphene–MoS2 SAs were 88.76%, 91.88% and 82.23% at 1064 nm, respectively, which were measured by a UV–Vis-NIR spectrophotometer. Their modulation depths on SiO2 substrate were measured to be 7.1%, 7.8% and 15.01% by the balanced synchronous twin-detector measurement system. Subsequently, these SAs (graphene SA, MoS2 SA, graphene and MoS2 SA, and graphene-MoS2 heterojunction SA) were placed in the same linear laser resonator, and their pulse output characteristics were systematically analysed and compared. When the absorbed pump power was 6.56 W, the heterojunction-based passively Q-switched Nd:YVO4 laser generated stable laser pulses with a pulse width of 180 ns and corresponding repetition rate of 640 kHz, which showed strongly enhanced saturable absorption properties than individual graphene (320 ns, 980 kHz), individual MoS2 (280 ns, 630 kHz), or graphene and MoS2 (248 ns, 760 kHz). And we attributed this mainly to rapid carrier relaxation induced by interlayer charge transfer in heterojunction because of type II band alignment. These results open up a possibility of actively regulating the saturable absorption properties of SAs by constructing heterojunctions with 2D materials.

A Review on Organic Materials for Optical Phase Conjugation & All-optical Switches

Nonlinear optical materials with optimum properties are essential in continuous development of photonic and electro-optical devices, used in optical communications, networking, optical computation for signal processing, and data storage equipments. The changing trend is to use organic materials/dyes that exhibit exceptional nonlinear optical properties instead of conventional materials which have comparatively low nonlinear properties. These organic materials/dyes are easy to prepare in solution or solid form. The resulting organic material has a low dielectric constant, eliminating the need for poling while maintaining the refractive index. However, these organic materials have few of the drawbacks inherent in the processing of comparable inorganic materials like of intense light induced degradation or bleaching and aggregation at higher dye concentration. In order to overcome these drawbacks and for effective use of highly nonlinear dyes, the dye molecules are doped in polymer matrix. This idea of dye-doped polymer material matrix may increase the concentration of absorptive or fluorescence centers as well as the opto-chemical and opto-physical stability. In this paper, we have discussed the strategic advantages of dye-doped polymer nonlinear materials in comparison with organic and inorganic nonlinear materials for optical phase conjugation and all optical switches in future photonics technology. This was done by studying the linear optical properties and nonlinear optical Phase Conjugation properties of two azo dye-doped polymer films by considering organic dyes disperse orange (DO-25) and disperse yellow (DY-7) doped in a polymer matrix Polymethyl methacrylate methacrylic acid (PMMA-MA). The nonlinear optical phase conjugation properties are studied using Degenerate Four Wave Mixing set-up using 532 nm wavelength CW laser beam. The effect of dye concentration, intensity of backward, forward pump, and inter beam angle between IJMIE Volume 6, Issue 1 ISSN: 2249‐0558 ________________________________________________________ A Monthly Double‐Blind Peer Reviewed Refereed Open Access International e‐Journal ‐ Included in the International Serial Directories Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A. International Journal of Management, IT and Engineering http://www.ijmra.us

Computational de Novo Design and Characterization of a Protein That Selectively Binds a Highly Hyperpolarizable Abiological Chromophore

This work reports the first example of a single-chain protein computationally designed to contain four α-helical segments and fold to form a four-helix bundle encapsulating a supramolecular abiological chromophore that possesses exceptional nonlinear optical properties. The 109-residue protein, designated SCRPZ-1, binds and disperses an insoluble hyperpolarizable chromophore, ruthenium(II) [5-(4'-ethynyl-(2,2';6',2″-terpyridinyl))-10,20-bis(phenyl)porphinato]zinc(II)-(2,2';6',2″-terpyridine)(2+) (RuPZn) in aqueous buffer solution at a 1:1 stoichiometry. A 1:1 binding stoichiometry of the holoprotein is supported by electronic absorption and circular dichroism spectra, as well as equilibrium analytical ultracentrifugation and size exclusion chromatography. SCRPZ-1 readily dimerizes at micromolar concentrations, and an empirical redesign of the protein exterior produced a stable monomeric protein, SCRPZ-2, that also displayed a 1:1 protein:cofactor stoichiometry. For both proteins in aqueous buffer, the encapsulated cofactor displays photophysical properties resembling those exhibited by the dilute RuPZn cofactor in organic solvent: femtosecond, nanosecond, and microsecond time scale pump-probe transient absorption spectroscopic data evince intensely absorbing holoprotein excited states having large spectral bandwidth that penetrate deep in the near-infrared energy regime; the holoprotein electronically excited triplet state exhibits a microsecond time scale lifetime characteristic of the RuPZn chromophore. Hyper-Rayleigh light scattering measurements carried out at an incident irradiation wavelength of 1340 nm for these holoproteins demonstrate an exceptional dynamic hyperpolarizabilty (β1340 = 3100 × 10(-30) esu). X-ray reflectivity measurements establish that this de novo-designed hyperpolarizable protein can be covalently attached with high surface density to a silicon surface without loss of the cofactor, indicating that these assemblies provide a new approach to bioinspired materials that have unique electro-optic functionality.

ChemInform Abstract: A Novel Class of Nonlinear Optical Materials Based on Host—Guest Composites: Zeolites as Inorganic Crystalline Hosts

AbstractReview: 94 refs.

A novel class of nonlinear optical materials based on host–guest composites: zeolites as inorganic crystalline hosts

The demand for nonlinear optical (NLO) materials with exceptional NLO properties is very large, and hence the search for such materials should be continued not only to enhance their functions in current applications but also to help expedite the materialization of photonics in which photons instead of electrons are used for signal processing, transmission, and storage. This article summarizes the preparation, characteristics, and the future perspectives of novel second order nonlinear optical (2NLO) materials prepared by orientation-controlled incorporation of 2NLO molecules into zeolite channels and third order nonlinear optical (3NLO) materials prepared by compartmentalization of very small (<1.3 nm) PbS QDs within zeolite nanopores under different environments, and the novel chemistry newly unveiled during the preparation of novel zeolite based NLO materials.

Origin of the nonlinear second-order optical susceptibilities of organic systems

An all-valence-electron self-consistent-field linear-combination-of-atomic-orbitals molecular-orbital procedure including configuration interactions for calculating the magnitude and sign of the nonlinear second-order molecular susceptibility components (hyperpolarizability) for substituted dipolar aromatic molecular systems is reported. Three fundamentally important examples, aniline, nitrobenzene, and $p$-nitroaniline, are considered. Analysis of the microscopic origin of their molecular second-order susceptibilities provides a direct means for understanding the macroscopic nonlinear optical response of organic molecular solids which have already been observed to possess exceptional nonlinear optical properties. The important excited states of aniline, nitrobenzene, and $p$-nitroaniline have been identified and examined in their relationship with the molecular second-order susceptibility-tensor components ${\ensuremath{\beta}}_{\mathrm{ijk}}$. The detailed nature of the charge separation accompanying these states has been discussed in terms of both the configurations composing the excited states, and also the one-electron molecular orbitals which determine those configurations. These results demonstrate how the bond-additivity approximation is inappropriate for $p$-nitroaniline. Finally, the frequency dependence of the ${\ensuremath{\beta}}_{\mathrm{ijk}}$ components in each case shows that the Kleinman relations are valid approximations only at relatively low frequencies.