Nonlinear Optical Applications Research Articles

Exploring structural and optical properties of shock wave-loaded polycrystalline picric acid: implications for molecular engineering applications

Abstract The shock wave impact on hydrogen-bonded organic materials’ structural properties and their responses with respect to their associated functional properties is one of the most prevalent research topics because of the possible emergence of unusual functional properties. Presently, we intend to examine the structural response of the poly-crystalline picric acid samples under shocked conditions. The crystallographic structural responses and the linear optical properties of the test samples have been examined by powder XRD analysis, ultra-violet diffused reflectance spectroscopy (UV-DRS) and Raman spectroscopy, respectively. Under shocked conditions, a considerable modification in the diffraction peak positions and their intensity changes could be witnessed. Notably, linear optical transmittance profiles show remarkable changes according to the number of applied shock pulses, such that the 150-shocked sample has the highest optical transmittance of 53.9 % at 350 nm, whereas the control sample has an optical transmittance of 6.6 %. The Raman spectrum shows the vibrational groups of material that are stable in shocked conditions with similar intensity changes. Based on the obtained XRD, UV-DRS and Raman results, shock wave-induced picric acid samples have remarkably improved characteristics of optical transmittance, which is highly favorable for non-linear optical applications.

New push–pull ladder-type chromophores with large hyperpolarizability for nonlinear optical application

New push–pull ladder-type chromophores with large hyperpolarizability for nonlinear optical application

Effect of partial substitution of K2O by MgO on the structure, and thermal, physical, optical properties and crystallization behaviour of K2O–MgO–B2O3–P2O5 glasses

In this work, a series of K2O–MgO–B2O3–P2O5 (KMBP) glasses were prepared by the melt-quenching method and the glass-ceramics were prepared by the one-step heat treatment. The thermal, structural, physical and optical properties, as well as the crystallization behaviour of the KMBP system, were investigated in detail using characterization techniques such as DSC, XRD, SEM, FTIR, transmittance spectroscopy and microhardness. As indicated by DSC, the thermostability and glass-forming ability were gradually enhanced through the partial substitution of K2O by MgO. XRD showed that the main crystalline phases of the glass-ceramics (GC) were gradually converted from the P–Mg–K–O based crystalline phases to the P–Mg–O based and the P–Al–O based crystalline phases. The SEM results indicated that tiny grain-like crystals were successfully precipitated from the parent glasses after heat treatment. The deconvoluted FTIR spectra results showed a gradual conversion of the [BO3] and [PO3] units towards the [BO4] and [PO4] units with the increase of the MgO contents. The increase in the degree of glass network polymerization was the essential reason for the increment in the microhardness of the parent glasses. The microhardness of GC featured a trend concordant with the crystallinity of the crystalline phases. The values of metallization criteria (MC) between 0.34 and 0.45, as well as the higher values of third-order nonlinear polarizability (χ(3)) and nonlinear refractive index (nnl) are indicative of the good suitability of the KMBP glasses for the nonlinear optical applications.

Theoretical investigation on the second order nonlinear optical properties of heptagon bridged bi-porphyrin derivatives

Porphyrins and their derivatives have drawn extensive attention as promising nonlinear optical (NLO) materials especially for biological applications owing to its large aromatic conjugation and special biological activity and compatibility. However, it is still critical to strategically design porphyrin derivatives materials with high performance in second order NLO applications and disclose the structure property correlation. In the present work, a series of dual-metallic-porphyrin derivatives are designed by incorporating a heptagon between two porphyrins with further addition of heteroatoms and metals. The doping of B and N along the dipole direction induces large static first hyperpolarizability, and strong charge transfer occurs with further introduction of Mg, thus ultimately achieving excellent second order NLO properties including strong sum frequency generation and difference frequency generations under external fields. The doping of heteroatoms and metals synergistically tunes the electronic structure of porphyrin-based derivatives and brings about high performance in biological nonlinear optics.

Modification in the Optical and Dielectric Characteristics of Poly (Vinyl Alcohol)/Carboxymethyl Cellulose Blended Polymers Doped with Two Phases Nanocomposites for Application in Optoelectronic and Energy Storage Devices

Nanocomposite films comprised of poly (vinyl alcohol) (PVA) and carboxymethylcellulose (CMC) were fabricated via a solution casting procedure, with the incorporation of (1-x)CuCo2O4/xZnMn2O4. Our research described here was aimed to explore the impact of the (1-x)CuCo2O4/xZnMn2O4 on the structural, optical and electrical features of the PVA/CMC blended polymer, using various techniques. The different phases formed (CuCo2 O4 and/or ZnMn2O4) in (1-x) CuCo2O4/x ZnMn2O4 filler samples were identified applying Rietveld refinement analysis. The structures and morphologies of the PVA/CMC/(1-x)CuCo2O4/xZnMn2O4 blend composites were determined using X-ray diffraction and scanning electron microscopy techniques. Their various linear and nonlinear optical parameters were examined using the diffused reflectance technique. The blended polymer composite with x = 0.1 displayed the highest absorbance. The transmittance of the PVA/CMC blend declined from 91 to 69% when it was loaded with a nanocomposite containing 10% ZnMn2O4. The optical band gaps of the doped blend composites had their lowest values, 5.45 eV for direct transition and (4.83, 2.99, 2.31) eV for the indirect transition, as the blend was loaded with the fillers containing 10 and 15% ZnMn2O4. The study also explored the influence of the (1-x)CuCo2O4/x ZnMn2O4 on the fluorescence spectra and chromaticity diagram of the PVA/CMC blend. The effect of the filler on the complex dielectric constant, complex electric modulus, ac conductivity and electrical storage energy of the host blend was examined. The obtained characteristics imply potential utility of the doped blends in photocatalytic, UV-blocking, UV-filtering, optoelectronic, electrical storage, nonlinear optical and photonic applications.

Influence of procion red dye doping on the structural, dielectric and optical properties of diglycine-phthalic acid single crystals for nonlinear optical applications

Influence of procion red dye doping on the structural, dielectric and optical properties of diglycine-phthalic acid single crystals for nonlinear optical applications

Growth and characterization of organic p-nitroacetophenone single crystals for nonlinear optical applications

Growth and characterization of organic p-nitroacetophenone single crystals for nonlinear optical applications

V2O5/Ti3C2 MXene-Based Solid-State Passively Mode-Locked Tm:YAP laser at 2 μm

In the present work, V2O5/Ti3C2 MXene hybrid nanomaterials were successfully synthesized. The morphology and structure of the prepared V2O5/Ti3C2 MXene were investigated, and the results showed excellent bonding and strong interaction between Ti3C2 MXene and V2O5 nanoparticles. The nonlinear absorption properties of V2O5/Ti3C2 MXene nanocomposites at 2 μm have been investigated using power transfer techniques, and the large modulation depth of the material gives it potential for applications in nonlinear optics. As a result, a 2 μm solid-state mode-locked pulsed laser with V2O5/Ti3C2 MXene as a saturable absorber has been realized for the first time, generating a pulsed laser output as short as 657 ps, which corresponds to an average output power of 0.67 W. The results show that the synthesized V2O5/Ti3C2 MXene hybrid nanomaterials, which have a large optical nonlinearity, can be applied to generating an ultrashort 2 μm pulsed laser.

Influence of Co(II) and Cd(II) metal ions on structural, electronic and nonlinear optical properties of 4-methoxypyridine-2-carboxylic acid complexes: An experimental and computational study

Molecular engineering of metal-organic frameworks has attracted increasing attention due to their potential technological applications in the fields of optics and photonics. Therefore, a number of organometallic complexes are investigated for nonlinear optical applications. The current research aimed to synthesize and investigate spectroscopic and nonlinear optical properties of two metal-organic coordination compounds, namely Co(MeOPic)2∙(H2O)2 and Cd(MeOPic)2∙(H2O)2. The FT-IR and UV-Vis spectra for the distorted octahedral Co(II) and Cd(II) complexes were recorded. In order to provide a deep understanding about the relation between structure and nonlinear optical properties, density functional theory studies were also applied to both of the complexes by using B3LYP/6–311++G(d,p)/LanL2DZ level. TG-DTA analysis demonstrated that Cd(II) complex is approximately stable up to 134 °C, and the same complex only loss the aqua ligands between 134 and 189 °C. Therefore, the main skeleton part continues to remain stable up to 208 °C. Static NLO studies also demonstrated that both complexes have weak responses due to centrosymmetric structures, while Co(II) complex is appropriate to third-order NLO applications (γ (0;0,0,0) = 148.70×10−36 esu and γ (-2w;w,w,0)=-1521.4×10−36 esu).

Hirshfeld surface analysis, experimental and theoretical evaluation of a new monohydrated organic salt of 2-amino-4‑hydroxy-6-methylpyrimidine (AHMP) and 4-acetamidobenzoic acid (AMBA) for nonlinear optical applications

The organic crystal (AHMP+.AMBA−) of the AHMP and AMBA organic compounds was successfully synthesized and grown by the slow evaporation solution process. The present work focuses on the crystal structure, Hirshfeld surface, spectroscopic and DFT analyses of the title salt. The crystal geometry of AHMP+.AMBA− monohydrated salt was characterized by the single-crystal XRD technique. The synthesized salt crystallizes in the triclinic crystal system and P-1 space group. The identification of the functional groups of the compound has been done by FTIR spectroscopy and DFT/B3LYP-D3/6–311++G(d,p) level of theory. Further, Hirshfeld surface mapping and its associated two-dimensional fingerprint plots predict that the O⋅⋅⋅H and H⋅⋅⋅H interactions are dominant for stabilizing the crystal structure. TG-DTA reveals the crystal is thermally stable up to 168 ºC. The optical studies have been performed by the time-dependent DFT (TD-DFT) and UV–Vis spectroscopic methods. Moreover, the Z-scan experiment has been done to obtain third-order NLO properties. Additionally, the HOMO-LUMO energy gap, MEP maps and theoretical NLO parameters have also been calculated.

Silicon‐Rich Nitride Refractive Index as a Degree of Freedom to Maximize Nonlinear Wave Mixing in Nanowaveguides

Silicon nitride is widely used in integrated photonics for optical nonlinear wave mixing due to its low optical losses combined with relatively high nonlinear optical properties and a wide‐range transparency window. It is known that a higher concentration of Si in silicon‐rich nitride (SRN) magnifies both the nonlinear response and optical losses, including nonlinear losses. To address the trade‐off, four‐wave mixing (FWM) is implemented in over a hundred SRN waveguides prepared by plasma‐enhanced chemical vapor deposition in a wide range of SRN refractive indices varying between 2.5 and 3.2 (measured in the C‐band). It is determined that SRN with a refractive index of about 3 maximizes the FWM efficiency for continuous‐wave operation, indicating that the refractive index of SRN is indeed a crucial optimization parameter for nonlinear optics applications. The FWM efficiency is limited by large nonlinear optical losses observed in SRN waveguides with indices larger than 2.7, which are not related to two‐photon absorption. Finally, the third‐order susceptibility and the nonlinear refractive index are estimated for multiple SRN refractive indices, and, specifically, the nonlinearities as large as and are estimated in a waveguide with an SRN refractive index of 3.2.

An insight into structural, spectroscopic and nonlinear optical Application of a promising malononitrile derivative: (Z)-2-(3-chloro-3-(4-chlorophenyl)allylidene)malononitrile

Conjugated organic single crystals play a pivotal role as donor-acceptor molecules, showcasing nonlinear optical properties due to their unique molecular structure. In the present study, a novel functionalised allylidene malononitrile derivative, (Z)-2-(3-chloro-3-(4-chlorophenyl)allylidene)malononitrile, was synthesised and subjected to various spectroscopic and structural analyses for its optical and structural characterisation. This compound serves as an essential building block in developing photonic and optoelectronic materials. We synthesised the compound through a Vilsmeier-Haack reaction followed by a Knoevenagel condensation reaction and crystallised it using a slow evaporation method. In addition to SCXRD, the structural analysis of the compound was performed using NMR (1H, 13C), mass spectroscopy and FT-IR spectroscopy. The Intermolecular interactions were studied using Hirshfeld surfaces. The optical properties were analysed using UV–visible and photoluminescence spectroscopy. The third-order nonlinearity of the grown crystal was estimated using the NLO coefficients via the widely recognised femtosecond Z-scan technique, equipped with Ti:sapphire-based laser oscillator using laser pulses of 90 fs and a wavelength of 500 nm at various incident powers. It was observed that with increasing laser power, the nonlinear absorption coefficient of the sample also increased. These findings, combined with the calculation of the nonlinear refractive index, conclusively establish the potential of (Z)-2-(3-chloro-3-(4-chlorophenyl)allylidene)malononitrile for optoelectronic applications.

Exploring induced smectic phases of hydrogen bond liquid crystals for nonlinear optical applications: Theoretical (DFT) and experimental approach

A new intermolecular hydrogen bond liquid crystal (HBLC) complex has been isolated and characterized. The HBLC complex is synthesized by mixing of non mesogenic (E)-3-(3,4,5-trimethoxyphenyl)prop‑2-enoic acid (3,4,5-Trimethoxycinnamic acid, TMCA) and mesogenic (E)-3-(4-Methoxyphenyl)prop‑2-enoic acid (4-Methoxycinnamic acid, 4MCA). Mesogenic textures and its LC parameters are analyzed using polarizing optical microscope (POM) and differential scanning calorimeter (DSC). The manifestation of cyclic dimer H-bonds between TMCA and 4MCA is confirmed via FTIR spectrum by observing peak at 3593cm−1 (OH) and C = O at 1683cm−1. It is noteworthy to observe that the induced smectic A (Sm A) with batonnets texture (during cooling cycle) at 129.3 °C and smectic G (Sm G) with multi color mosaic texture at 116.5 °C in TMCA+4MCA, while compared to its individuals. To understand the molecular level modifications in the LC phases, with the aid of density functional theory (DFT), the nature (H-bond length, MEP, FMO, QTAIM, etc.,) and strength of intermolecular H-bonds are explored. The NLO parameters of HBLC complex have been discussed. In this present paper, the DFT result is compared with experimental observations and the special significances are studied to identify the potent applications of HBLCs.

Generation of Propagation-Dependent OAM Self-Torque with Chirped Spiral Gratings

The application of non-uniform spiral gratings to control the structure, topological parameters and propagation of orbital angular momentum (OAM) beams was studied experimentally with coherent near-infrared light. Adapted digital spiral grating structures were programmed into the phase map of a high-resolution liquid-crystal-on-silicon spatial light modulator (LCoS-SLM). It is shown that characteristic spatio-spectral anomalies related to Gouy phase shift can be used as pointers to quantify rotational beam properties. Depending on the sign and gradient of spatially variable periods of chirped spiral gratings (CSGs), variations in rotation angle and angular velocity were measured as a function of the propagation distance. Propagation-dependent self-torque is introduced in analogy to known local self-torque phenomena of OAM beams as obtained by the superposition of temporally chirped or phase-modulated wavepackets. Applications in metrology, nonlinear optics or particle trapping are conceivable.

Room temperature excitonic coupling in self-assembled copper – Fullerene hybrid films exposed to ambient air

Analytically sound combination of organic and inorganic semiconductors in designing functional hybrid nanomaterials promises new advances in nanoscience and in creation of next-generation optoelectronic devices. In this work, we report on combining two contrasting semiconductors (inorganic and organic) possessing attractive optical and electronic properties, namely Cu2O (in form of small single-crystalline nanoparticles, NPs) and C60-fullerene (as a medium supporting the NP ensemble), which were formed within the well-controlled Cux(Oy)C60 hybrid films through self-assembling and ambient air exposure of the vapour-deposited Cu and C60 mixture. The controllability of the hybrid film nanostructure was established and verified through systematic study of the films using Rutherford backscattering spectrometry, transmission electron microscopy, X-ray diffraction, Raman spectrometry and spectroscopic ellipsometry. The remarkable coincidence of the optical absorption peaks around 3.5 eV, reported for the Wannier-Mott (WM) excitons in a Cu2O crystal and detected for the Frenkel (F) excitons in the pristine C60 film, allowed us to observe room temperature polaritons as a product of the F-WM excitonic strong coupling. Quite high coupling energy of the FWM hybrid exciton estimated for the Cux(Oy)C60 films in the x interval of 5 < x < 15 (from 390 meV to 610 meV) implies the mediated effect of nanocavity photons and quantum confinement effect, strongly enhancing the hybrid exciton coupling energy. The implemented study discloses the self-assembled Cux(Oy)C60 hybrid films as promising material for application in optoelectronics and nonlinear optics.

Rational design and investigation of nonlinear optical response properties of pyrrolopyrrole aza-BODIPY-based novel push-pull chromophores.

Intramolecular charge transfer (ICT)-based chromophores are highly sought after for designing near-infrared (NIR) absorbing and emitting dyes as well as for designing materials for nonlinear optical (NLO) applications. The properties of these 'push-pull' molecules can easily be modified by varying the electronic donor (D) and acceptor (A) groups as well as the π-conjugation linker. This study presents a methodical approach and employs quantum chemical analysis to explore the relationship between the structural features, electro-optical properties, and the NLO characteristics of molecules with D-π-A framework. The one- and two-photon absorption (2PA), linear polarizability (α), and first hyperpolarizability (β) of some novel chromophores, consisting of a dimeric aza-Boron Dipyrromethene (aza-BODIPY) analogue, called, pyrrolopyrrole aza-BODIPY (PPAB), serving as the acceptor, have been investigated. The electronic donors used in this study are triphenylamine (TPA) and diphenylamine (DPA), and they are conjugated to the acceptor via thienyl or phenylene π-linkers. Additionally, the Hyper-Rayleigh Scattering (βHRS), which enables direct estimation of the second-order NLO properties, is calculated for the studied chromophores with 1064 nm excitation in acetonitrile. The β value shows a significant increase with increasing solvent polarity, indicating that the ICT plays a crucial role in shaping the NLO response of the studied molecules. The enhancement of the 2PA cross-section of the investigated molecules can also be achieved by modulating the combinations of donors and linkers. The results of our study indicate that the novel D-π-A molecules designed in this work demonstrate considerably higher hyperpolarizability values than the standard p-nitroaniline, making them promising candidates for future NLO applications.

Halide Perovskite Inducing Anomalous Nonvolatile Polarization in Poly(vinylidene fluoride)-based Flexible Nanocomposites

Ferroelectric materials have important applications in transduction, data storage, and nonlinear optics. Inorganic ferroelectrics such as lead zirconate titanate possess large polarization, though they are rigid and brittle. Ferroelectric polymers are light weight and flexible, yet their polarization is low, bottlenecked at 10 μC cm−2. Here we show poly(vinylidene fluoride) nanocomposite with only 0.94% of self-nucleated CH3NH3PbBr3 nanocrystals exhibits anomalously large polarization (~19.6 μC cm−2) while retaining superior stretchability and photoluminance, resulting in unprecedented electromechanical figures of merit among ferroelectrics. Comprehensive analysis suggests the enhancement is accomplished via delicate defect engineering, with field-induced Frenkel pairs in halide perovskite stabilized by the poled ferroelectric polymer through interfacial coupling. The strategy is general, working in poly(vinylidene fluoride-co-hexafluoropropylene) as well, and the nanocomposite is stable. The study thus presents a solution for overcoming the electromechanical dilemma of ferroelectrics while enabling additional optic-activity, ideal for multifunctional flexible electronics applications.

Experimental and theoretical investigation on the SR method grown semi-organic Piperazinium Tetrachlorozincate Monohydrate (PTZM) single crystal for optoelectronic applications

Efficient semi organic nonlinear optical (NLO) Piperazinium Tetrachlorozincate monohydrate (PTZM) [C4H12N2][ZnCL4]·H2O single crystals have been grown by slow evaporation solution technique (SEST) and Sankaranarayanan-Ramasamy (SR) method using water as solvent. Single crystal X-ray diffraction (SXRD) analysis reveals the unit cell parameters of the grown crystal. The morphology of the grown crystal was identified by the single crystal XRD analysis. The electrical properties, dielectric constant, dielectric loss and piezoelectric (d33) coefficient were determined. The etch pit density of PTZM crystal has been calculated by using the chemical etching analysis. The laser damage threshold (LDT) analysis was investigated by Nd: YAG laser and the wavelength of laser is 1064 nm. The mechanical stability of the grown PTZM crystal was studied using Vickers microhardness measurement. Utilizing quantum chemical calculations, the PTZM compound is analyzed for vibrational properties, HOMO and LUMO characteristics, NBO interactions, and the determination of first-order hyperpolarizability. The nonlinear susceptibility and first-order hyperpolarizability results provide compelling evidence and affirm the PTZM molecule’s potential as a strong candidate for nonlinear optical (NLO) applications.

Exploring the spectral properties and potential applications of dimethylamine-modified porphyrin and chlorin dyes

The synthesis, structural characterization, and optical properties of new free-base and metalated dimethylamine-based porphyrin (1, 1a) and chlorin (2, 2a) derivatives are presented. The synthetic approach is based on the peripheral substitution of the para-fluor atoms of the commercially available 5,10,15,20-tetrakis(pentafluorophenyl)-21H,23H-porphyrin (H2TPPF20) by dimethylamine (H2Por 1), following the preparation of the analogous chlorin dye (H2Chl 2) using N-methylglycine and p-formaldehyde. Both compounds were then metalated with zinc acetate to perform the corresponding ZnPor 1a and ZnChl 2a dyes. Several photophysical parameters were determined, including absorption and emission features at 298 K (e.g., molar absorptivity coefficients, λ absorption maxima of Soret and/or Q bands, λemission maxima, and ratio of long- to short-wavelength emission intensity), fluorescence quantum yield (ФF), stability (under dark conditions), and photostability (under white light exposure at irradiance of 50 mW.cm−2). The photophysical results were determined and compared for the type of meso-substituted scaffold selected – A4-type – of free-base (1, 2) and zinc(II) complex (1a, 2a). The four compounds exhibit high dark stability in DMF (absorption reduction intensity < 3 %). The Pors 1 and 1a have also high photostability (absorption reduction intensity < 1.5 %), but H2Chl 2 and ZnChl 2a present a considerable absorption reduction, 14.3 % and 22.3 %, respectively. The ФF of the ZnPor 1a (ФF = 0.02) and H2Por 1 (ФF = 0.02) are lower than those of ZnChl 2a (ФF = 0.06) and H2Chl 2 (ФF = 0.09). The developed compounds present potential applications in nonlinear optics, biomarkers, and/or solar cells.

A Comprehensive Review and Future Perspectives of Nanomaterials in Nonlinear Optics and Photonics

Purpose: Nanomaterials have sparked a paradigm shift in nonlinear optics and photonics, presenting unparalleled advantages over bulk materials. Their distinctive attributes, encompassing a substantial surface area, customizable optical properties, and quantum confinement effects, position them as optimal candidates for an array of nonlinear optical applications. Despite their immense potential, the field faces several challenges and future directions. These encompass tailoring nanomaterials for precise applications, establishing scalable fabrication methods, ensuring device stability, broadening application scopes, comprehending fundamental nonlinear optical mechanisms, and advancing predictive theoretical models. Addressing these challenges promises to propel nonlinear optics and photonics into new frontiers, fostering technological advancements that benefit society across multiple domains. Methodology: This paper uses exploratory research methodology to analyse, compare, evaluate, interpret, and create new knowledge to address the challenges and to predict future perspectives of nanomaterials in nonlinear optics and photonics by collecting relevant information using appropriate keywords through Google, Google scholar, and AI-driven GPT search engines. Results &amp; Discussion: This paper underscores nanomaterials' transformative impact on nonlinear optics and photonics. With their unparalleled characteristics and versatile applications, nanomaterials are poised to revolutionize various technologies, offering innovative solutions to contemporary challenges and heralding a new era of scientific progress and technological innovation in various fields including development of Optical Computers. Originality/Value: The paper explores the significance of Nanomaterials in Nonlinear Optics and Photonics, overviews the characteristics of nanomaterials in nonlinear Optics, identifies various important Applications of Nanomaterials in Nonlinear Optics and Photonics, evaluates Prominent Nanomaterials in Nonlinear Optics, and hence analyses and interprets Challenges and Future Directions. Type of Paper: Exploratory Study.