Nonlinear Optical Applications Research Articles

Structural, physical and optical study of calcium modified bismuth borovanadate glasses: V2O5-B2O3-Bi2O3-CaO

Comprehensive research into quaternary glass systems' structural, physical, and optical characteristics was conducted, specifically for glass series 60V2O5-20B2O3-(20-x)Bi2O3-xCaO, where x = 0-20 mol%. Using X-ray diffraction (XRD), their non-crystalline character was confirmed. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) were used for morphological study to confirm glass formation. Several techniques were employed to investigate the effects of incorporating CaO on the physical, optical, and structural characteristics of glasses composed of bismuth boro-vanadate. As-prepared glass samples have been analysed to determine how density (ρg), crystalline volume (Vcryst), molar volume (Vm), and oxygen packing density (OPD) changes with composition. Additional determined physical parameters include interionic distance (Ri), Calcium yields field (F), ion concentration of Ca2+ (N), and polaron radius (Rp). DSC thermograms reveal that glass transition temperature (Tg) rises in tandem with the concentration of calcium oxide, demonstrating an improvement in the glass system's thermal stability. FTIR and Raman spectroscopy examination of all glass samples confirmed that V2O5 forms a network with VO5 units. After x = 10 mol%, the proportion of non-bridging oxygens in the glass matrix rises as VO5 units are converted into VO4 units along with the transformation of BO3 units into BO4 units. Bi2O3 is found in glass matrix in BiO6 and BiO3 units. As concentrations of calcium oxide were increased, UV–Visible spectroscopy revealed nonlinear trends in various optical parameters such as optical energy (Eopt), Urbach energy (EU), cut-off wavelength (λC), molar refractivity (RM), metallization criterion, and refractive index (n). The glasses prepared in this study exhibit high-level optical basicity (ranging from 1.164 to 1.238), electronic oxide ion polarizability (3.304–3.869), and metallization criterion (0.249–0.304). These findings point to the possibility that the glasses can be suitable for non-linear optical applications.

Third order nonlinear investigations of CuLaSe2 and ZnCuLaSe2 quantum dots

Environmentally friendly quantum dots (QDs) with high two-photon absorption coefficients in the near-infrared region are important for nonlinear optics (NLO) applications. In this work, CuLaSe2 and ZnCuLaSe2 QD are successfully synthesized and characterized using UV–Vis, Photoluminescence and HRTEM analysis. Next, the third-order NLO properties of these materials are studied using the femtosecond Z-scan method. The samples showed efficient nonlinear responses. The nonlinear absorption coefficient (β), the nonlinear refractive index (n2) and the third-order nonlinear susceptibility (χ(3)) values for all samples are deduced and discussed in detail. The results reported here pave the way towards building CuLaSe2 and ZnCuLaSe2 QDs-based nonlinear photoelectric devices operating in the near-infrared field.

Experimental and Computational studies on Intramolecular charge transfer, Terahertz and Two photon absorption of 3-[(4-Nitrophenyl Azo)]-9H-Carbazole-9-Ethanol (NPACE) from their Vibrational spectra for Optical limiting and NLO applications

Non-linear optical (NLO) features of 3-[(4-Nitrophenyl Azo)]-9H-Carbazole-9-Ethanol (NPACE) chromophore were investigated by FT-IR, FT-Raman, and UV–visible spectra aided by Density Functional Theory (DFT) using the B3LYP/6–311++G(d,p) basis set of Gaussian 16 W package. It is observed from the DFT calculation that the slight increase in the endocyclic angle of C13 -C14 -C15 and the reduction in exocyclic angle of N40 –N39 -C14 and C15 -C14 –N39 ascertained by experimental XRD values indicating the intramolecular charge-transfer interaction between the carbazole and nitrophenyl group through the diazo bridge. The vibrational contribution to the linear electro-optic effect is 15% of the total hyperpolarizability being calculated at B3LYP/6–311++G (d, p) for the NPACE molecule. It is also observed that the 8a, 19a, and 19b modes of the carbazole ring and the 8a, 8b, and 19b modes of the phenyl ring are found to be simultaneously and intensely active in IR and Raman spectra explaining the charge transfer interactions throughout the molecule. The low value of the HOMO- LUMO energy gap (2.5843 eV) and the deviation between the measured absorption wavelength (3.36 eV) from the computed (3.87 eV), both these facts substantiate the intramolecular charge transfer. The polarizability and first-order hyperpolarizability were calculated as 6.48 × 10-24 and 3.8 × 10-29 esu, respectively. The second harmonic generation (SHG) measurement experiment of NPACE was carried out using the powder method. The SHG efficiency is measured in comparison with the urea standard. The calculated torsional mode at 20 cm−1 is in excellent quantitative agreement with the experimentally determined terahertz absorption peak. The two-photon absorption coefficient of NPACE was estimated to be 0.9 × 10-11 mW−1, which is mainly due to the D-π-A type of molecular structure, and the optical limiting threshold for NPACE was estimated to be 1.52 × 1013 Wm−2 enabling this material as a potential candidate for optical limiting applications.

Nitrogen-doped graphene quantum dots for femtosecond ultrafast pulsed fiber lasers

Nitrogen-doped graphene quantum dots (N-GQDs) are a new class of quantum dot with unique electronic properties, whose electrons transport and biochemical properties have been extensively studied. However, the optical properties of N-GQDs, especially their nonlinear optical response and applications in ultrafast photonics and photoelectronic, need to be further explored. The nonlinear optical response and ultrafast carrier dynamics of N-GQDs in an aqueous solution are systematically investigated in this work. N-GQDs have an ultrafast carrier cooling delay of about 143 fs in the visible range. In the study of the nonlinear optical response of N-GQDs, the saturable absorption is transformed into reverse saturable absorption as the incident pulse intensity increases, which makes N-GQDs an effective saturable absorber for ultrashort pulse generation in mode-locked Er-doped fiber lasers. Our results may lead to further investigations into the optical properties of N-GQDs and demonstrate potential opportunities for ultrafast photonic applications.

N‐Doped Nonalternant Nanoribbons with Excellent Nonlinear Optical Performance

AbstractTwo novel N‐doped nonalternant nanoribbons (NNNR‐1 and NNNR‐2) featuring multiple fused N‐heterocycles and bulky solubilizing groups were prepared via bottom‐up solution synthesis. NNNR‐2 achieves a total molecular length of 33.8 Å, which represents the longest soluble N‐doped nonalternant nanoribbon reported to date. The pentagon subunits and doping of N atoms in NNNR‐1 and NNNR‐2 have successfully regulated their electronic properties, achieving high electron affinity and good chemical stability enabled by the nonalternant conjugation and electronic effects. When applied a laser pulse of 532 nm, the 13‐rings nanoribbon NNNR‐2 shows outstanding nonlinear optical (NLO) responses, with the nonlinear extinction coefficient of 374 cm GW−1, much higher than those of NNNR‐1 (96 cm GW−1) and the well‐known NLO material C60 (153 cm GW−1). Our findings indicate that the N‐doping of nonalternant nanoribbons is an effective strategy to access another type of excellent material system for high‐performance NLO applications, which can be extended to construct numerous heteroatom‐doped nonalternant nanoribbons with fine‐tunable electronic properties.

N-Doped Nonalternant Nanoribbons with Excellent Nonlinear Optical Performance.

Two novel N-doped nonalternant nanoribbons (NNNR-1 and NNNR-2) featuring multiple fused N-heterocycles and bulky solubilizing groups were prepared via bottom-up solution synthesis. NNNR-2 achieves a total molecular length of 33.8 Å, which represents the longest soluble N-doped nonalternant nanoribbon reported to date. The pentagon subunits and doping of N atoms in NNNR-1 and NNNR-2 have successfully regulated their electronic properties, achieving high electron affinity and good chemical stability enabled by the nonalternant conjugation and electronic effects. When applied a laser pulse of 532 nm, the 13-rings nanoribbon NNNR-2 shows outstanding nonlinear optical (NLO) responses, with the nonlinear extinction coefficient of 374 cm GW-1 , much higher than those of NNNR-1 (96 cm GW-1 ) and the well-known NLO material C60 (153 cm GW-1 ). Our findings indicate that the N-doping of nonalternant nanoribbons is an effective strategy to access another type of excellent material system for high-performance NLO applications, which can be extended to construct numerous heteroatom-doped nonalternant nanoribbons with fine-tunable electronic properties.

Influence of azo-based donor modifications on nonlinear optical amplitude of D-π-A based organic chromophores: A DFT/TD-DFT exploration

Organic heterocyclic fused ring compounds possess remarkable nonlinear optical (NLO) amplitude, are potentially employed in optical computing and nano-photonics. Herein, ITTBCR1 was quantum chemically modified into a series of novel D-π-A configured NLO compounds (ITTBCD2-ITTBCD6) by substituting various efficient donor moieties. To investigate the electronic, photophysical, and NLO properties, ITTBCR1 and ITTBCD2-ITTBCD6 were subjected to density functional theory (DFT) and time-dependent DFT calculations at M06/6–311 G(d,p) level of theory. Frontier molecular orbital analysis (FMOs) illustrated that the newly designed chromophores exhibit smaller energy gaps (1.625–2.013 eV) compared to ITTBCR1 (2.384 eV). The global reactivity parameters estimated through Egap revealed higher softness (σ = 0.49–0.61 Eh) values, implying enhanced reactivity of ITTBCD2-ITTBCD6 compounds. An efficient push-pull mechanism disclosed positive charges on donors and π-spacers, while the acceptor moieties exhibited a negative charge. The presence of charge separation states and the substantial involvement of molecular orbitals in the charge transfer were explored by natural bond orbitals (NBOs), transition density matrix and density of states analyses. The UV-Vis study of the designed compounds displayed larger bathochromic shifts with wider absorption spectra. Also, a significantly large NLO behavior was found in all the novel entities (ITTBCD2-ITTBCD6), thus potentially employable as NLO materials. Inclusively, compound ITTBCD5 demonstrated highest linear polarizability (〈α〉 = 2.250 ×103a.u.), and first hyperpolarizability (βtot = 70.155 ×104a.u.), therefore proposed as the most proficient NLO material. Comparative study for NLO properties at various functional showed that at M06/6–311 G (d,p) significant NLO results could be obtained. The current investigation revealed that by controlling the type of donor motifs, numerous NLO compounds can be designed, which are equally productive in hi-tech NLO applications.

Tunable Bound States in the Continuum in a Reconfigurable Terahertz Metamaterial

AbstractBound states in the continuum (BIC) is an exotic concept describing systems without radiative loss. BICs are widely investigated in optics due to numerous potential applications including lasing, sensing, and filtering, among others. This study introduces a structurally tunable BIC terahertz metamaterial fabricated using micromachining and experimentally characterized using terahertz time domain spectroscopy. Control of the bending angle of the metamaterial by thermal actuation modifies the capacitance enabling tuning from a quasi‐BIC state with a quality factor of 26 to the BIC state. The dynamic response from the quasi‐BIC state to the BIC state is achieved by blueshifting the resonant frequency of the LC mode while maintaining a constant resonant frequency for the dipole mode. Additional insight into the tunable electromagnetic response is obtained using temporal coupled mode theory (CMT). The results reveal the effectiveness of bi‐layer cantilever‐based structures to realize tunable BIC metamaterials with potential applications for nonlinear optics and light‐matter control at terahertz frequencies.

Design of a negative curvature hollow-core fiber for transmitting a single-mode dark hollow beam

We propose a nested negative curvature hollow-core fiber that can stably transmit a single-mode (LP11 mode) dark hollow beam with low loss. A pair of resonant tubes is nested inside the cladding tubes in the horizontal direction to enhance the confinement loss of the fundamental mode LP01. Two pairs of glass sheets at different positions within the four cladding tubes in the non-horizontal direction are introduced to suppress the comparatively low loss higher-order modes LP21 and LP02. The numerical simulation results indicate that the loss ratio between the fundamental mode and LP11 mode can reach 28703 when the transmission wavelength is 1.54 µm, and the LP11 mode has the lowest confinement loss of 0.0049 dB/m. Meanwhile, the loss ratios of higher-order modes such as LP21, LP02, and LP31 with the target LP11 mode are above 100. The effective bandwidth of single-mode dark hollow beam transmission can reach 5 nm. This provides an optical fiber solution for single-mode dark hollow beam transmission, which has potential applications in atomic optics, quantum information, and nonlinear optics.

A combined theoretical and experimental study of the D-2-aminobutyric acid L-norvaline single crystal for efficient third-order nonlinear optical (NLO) applications

Here we report, the formation of an optically active single crystal of D-2-aminobutyric acid L-Norvaline (ABANV) by the slow evaporation technique by co-crystallization of amino acids D-2-aminobutyric acid (ABA) and L-Norvaline together in water. An X-ray diffraction technique has been used to determine the dimensions of the single crystal unit cells. The functional group of ABANV crystal was studied using FTIR spectroscopy in order to determine its chemical structure. The FT NMR spectrum was conducted to analyze the carbon and hydrogen environments of the grown crystal. In optical absorption studies, the crystal was shown to be transparent in the visible region with a lower cut off wavelength of 236 nm, which led to an optical band gap energy Eg of 5.25 eV. In addition, using TG/DSC techniques, we have investigated the thermal stability of the grown ABANV single crystal as well as their accurate melting point. A HOMO and LUMO analysis were performed to determine the electronic charge distribution and reactivity of the molecules within the crystal. First-order molecular hyperpolarizality (β) properties of the grown crystal have been determined using the B3LYP method. The scatter graph provides an explanation of the chemical bonding of ELF and LOL, as well as the inter and intra fragment interactions.

Phthalocyanine‐Based 2D Polymer for Ultrafast Nonlinear Optical Application

AbstractStrong ultrafast nonlinear optical (NLO) responses in near‐infrared (NIR) regions and favorable solution processability are two urgent requirements for practical NLO applications, especially for optical limiting (OL) applications. However, simultaneously optimizing these properties remains significant challenging. In this study, the successful synthesis of a phthalocyanine‐based 2D polymer (Pc‐2DP) is reported; its structure features extended π‐electrons delocalization space constructed by topologically integrating the phthalocyanine units into the 2D framework. The as‐prepared few‐layered Pc‐2DP not only exhibits power‐ and wavelength‐dependent NLO properties toward 35 fs ultrafast pulsed laser, but it also demonstrates excellent ultrafast reverse saturable absorption (RSA) responses in NIR regions. The nonlinear absorption coefficients of Pc‐2DP dispersion reach up to 0.12 and 0.19 cm GW−1 at 800 and 1550 nm, respectively, which are much higher than those of the typical MXene (Ti3C2TX) and molybdenum disulfide with hexagonal structure (2H‐MoS2). The obtained NLO devices exhibit remarkable OL performance at 800 nm and, particularly, in the telecommunication region (1300 to 1550 nm), which is highly desired but seldom reported. The study demonstrates that the as‐prepared Pc‐2DP featuring a highly conjugated aromatic framework is a very promising OL material and that this research provides a new strategy for developing high‐performance 2D organic NLO polymers.

Nucleophilic reactions with the novel 7-(chromon-3-yl)quinolino [3′,4′:5,6] pyrano[3,2-c]quinoline: Synthesis, biological and computational studies

Condensation reaction of 3-formylchromone (1) with 1-ethyl-4-hydroxyquinolin-2(1H)-one (2) in glacial acetic acid afforded the condensation product 4; in 1:2 molar ratio. Compound 4 was used as precursor for construction of some propenones linked pentacyclic quinolinopyranoquinoline. Ring opening of chromone moiety in compound 4 was achieved via reactions with a diversity of primary amines leading to propenone derivatives 5–7 and 11–13 in good yields (62–73%). All propanone derivatives exist in the E-configuration as deduced from their 1H NMR spectra. DFT/B3LYP functional was used with 6–311+G(d,p) basis sets for all theoretical calculations. Based on optimized geometry, the chemical potential (Pi), electronegativity (χ), hardness (η) and electrophilicity index (ω) are some of the global reactivity descriptors that were computed to predict the chemical reactivity of the studied compounds; where compound 13 has the highest softness and electrophilicity index (ω). Moreover, to determine the relative stability of compounds 1–4, the thermodynamic parameters such as enthalpy and free energies of the reactions were computed; where compound 4 has the lowest free energy of reaction (-439.61 kcal/mol), so its formation is spontaneous. By utilizing molecular electrostatic potential (MEP) and local-based descriptors in the form of condensed Fukui functions of the starting compound 4, the susceptible sites for electrophilic and nucleophilic attack were investigated. For compound 4, fk+ and Δfk values are more positive at C9 and C7 than other sites and these sites have more electrophilic characters. Therefore, nucleophilic attacks began at C9. On the other hand, the GIAO approximation was used to compute the 1H and 13C NMR chemical shift values in the ground state, of the present compounds, where a good agreement was observed between experimental and theoretical chemical shift results. Further, the calculated first hyperpolarizability of prepared compounds are found to be greater than that of urea. So, these compounds are ideal candidates for non-linear optical applications. The synthesized compounds were screened for their antimicrobial and anticancer activities showing variable inhibitory action. Compounds 5, 7 and 13 were more effective antimicrobial candidates against all tested microorganisms, while compound 13 was the most active against HepG-2 cell lines. Furthermore, a quantitative structure–activity relationship (QSAR) (relationship between DFT calculated descriptors and biological activities pIC50) model was built by applying multiple linear regression (MLR) on the synthesized compounds as anticancer agents. Moreover, Lipinski's rule of five indicates no problems with oral bioavailability of the prepared compounds.

Thermal, dielectric, mechanical and structural behavior of 2-amino 4-methylpyridinium 4-nitrophenolate 4-nitrophenol bulk single crystal

Applications in both science and industry have received increased attention as a result of bulk single crystals with particular orientations. However, due to the instability of organic crystals at high temperatures and stress, there is an interest in growing good-quality bulk single crystals with stable thermal and mechanical properties. Here, the 2-amino 4-methylpyridinium 4-nitrophenolate 4-nitrophenol (2A4MPPP) crystal was prepared employing a single-wall ampoule and the vertical Bridgman technique. Structure and functional groups were determined by XRD, NMR, and FTIR studies. More importantly, detailed thermal and kinetic properties such as activation energy, frequency factor, rate constant, and Avrami exponent are discussed. The mechanical stability and dielectric studies are also demonstrated for the title compound. According to the single crystal XRD investigation, 2A4MPPP is a member of the orthorhombic crystal system with the Pna21 space group. Through the TGA and DTA analyses, it was confirmed that the compound starts to melt at 98 °C and complete melting occurs at 103.3 °C. The dielectric experiments reveal the crystal's poor dielectric constant and high-frequency dielectric loss. Vickers microhardness investigations show that grown 2A4MPPP belongs to the soft materials group. As a result of these findings, the 2A4MPPP crystal should be well suited for usage in thermomechanical, microelectronic, optical communications, and nonlinear optical applications.

Growth of piperazinium bis(trifluoroacetate) (PTFA) single crystal for nonlinear optical (NLO) application

Growth of piperazinium bis(trifluoroacetate) (PTFA) single crystal for nonlinear optical (NLO) application

NLO azo compounds with sulfonamide groups: A theoretical investigation

The linear and nonlinear optical properties such as the dipole moment, polarizability, electric field–induced second harmonic generation, and hyper–Rayleigh scattering first hyperpolarizability of four heterocyclic azo compounds have been calculated and analysed extensively using density functional theory. The relationship between the structure, electric field–induced second harmonic generation, and hyper–Rayleigh scattering responses are evaluated. The relationship between the static first hyperpolarizability and energy gap is also taken into account. These azo compounds are found to have reduced HOMO-LUMO energy gap at the PBE0 level, large value of second order nonlinear optical susceptibility βHRS up to 2.8×102 a.u. was obtained at the same PBE0 level, and a significant donor character in the case of HAC2, HAC3 and HAC4 azo compounds, these factors render them suitable for nonlinear optical applications.

Growth and characterization of organic 2,4-dihydroxybenzophenone single crystals for nonlinear optical applications

Growth and characterization of organic 2,4-dihydroxybenzophenone single crystals for nonlinear optical applications

Mid-infrared integrated silicon–germanium ring resonator with high Q-factor

We report the realization of a silicon–germanium on silicon ring resonator with high Q-factor at mid-infrared wavelengths. The fabricated ring exhibits a loaded Q-factor of 236 000 at the operating wavelength of 4.18 µm. Considering the combined waveguide propagation losses and bending losses, which are measured to be below 0.2 dB/cm, even higher Q-factors could be achieved on this platform. Furthermore, our dispersion engineering of the waveguides should make these microrings suitable for nonlinear optical applications. These results pave the way for sensing applications and nonlinear optics in the mid-infrared range.

Synthesis, spectral characterization, SC-XRD, Hirshfeld, DFT and in silico antidiabetic activity of novel imine (E)-N-(2-nitro benzylidene) naphthalene-1-amine, a newly synthesized imine: A theoretical and experimental evaluation

A novel imine compound, (E)-N-(2-nitrobenzylidene) naphthalene-1-amine (NBNA), has been successfully synthesized through the reaction of o-nitrobenzaldehyde and 1-naphthylamine. The structural characterization of NBNA has been carried out using single-crystal X-ray diffraction (SC-XRD) analysis. The XRD analysis reveals that NBNA crystallizes in a monoclinic crystal system with the space group P21/c. The unit cell parameters of NBNA are determined as follows: a = 7.549 (4) Å, b = 19.680 (11) Å, c = 9.598 (6) Å, β = 107.96(3)°, and Z = 4. Notably, the crystal structure of NBNA is stabilized by π-π stacking interactions between the naphthyl moiety and the nitrophenyl moiety, occurring at a perpendicular distance of 3.542 Å. Quantum mechanical calculations employing the B3LYP/6–311G(d,p) method in GAUSSIAN 09 software have been employed to determine the optimized geometry, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO), Time-dependent Density Functional Theory (TD-DFT), and chemical reactivity descriptors of NBNA. The vibrational spectroscopic data has been compared with the DFT/B3LYP/6–311G(d,p) method and scaled using MOLVIB for analysis. By examining the NBOs, the distribution of electron density and the interaction between orbitals can be analysed, shedding light on the stability and reactivity of the compound. Additionally, frontier molecular orbital analysis and molecular electrostatic potential mapping are discussed to gain further insights. First-order hyperpolarizability studies have been conducted to explore the nonlinear optical behaviour of the molecule. By calculating and comparing the first-order hyperpolarizability of the compound with a reference molecule (in this case, urea), the obtained results indicate that the crystal of the molecule possesses a significantly higher first-order hyperpolarizability value (19.124 times urea) suggesting its potential as a promising material for nonlinear optical applications. An in-depth examination of the Hirshfeld surface and two-dimensional fingerprint plot has been conducted to gain insights into the intermolecular interactions of the compound. Molecular docking studies are performed on the PPARγ target to assess the molecule's potential antidiabetic activity, revealing a binding energy of -6.71 kJ/mol for NBNA with the target. The comprehensive assessment of the compound's ADMET properties provides valuable insights into its pharmacological potential and aids in the selection of promising drug candidates.

Cuminaldehyde-3-hydroxy-2-napthoichydrazone: Synthesis, effect of solvents, nonlinear optical activity, antioxidant activity, antimicrobial activity, and DFT analysis

Hydrazones derived from essential oil components have attracted considerable interest because of their antimicrobial, antioxidant, and nonlinear optical applications. In the present work, a new essential oil component derivative (EOCD), cuminaldehyde-3-hydroxy-2-napthoichydrazone (CHNH), was synthesized. EOCD was characterized by Fourier transform infrared spectroscopy, mass spectrometry, nuclear magnetic resonance (1H and 13C) spectroscopy, elemental analysis, ultraviolet–visible absorption spectroscopy, and field-emission scanning electron microscopy. Thermogravimetric analysis and X-ray diffraction showed a higher stability, phase-pure, and non-existent isomorphic phase transition in EOCD. Solvent studies indicated that the normal emission band was caused by the locally excited state and the large Stokes shifted emission originated because of the twisted intramolecular charge transfer. The EOCD possessed higher direct and indirect band gap energies of 3.05 eV and 2.90 eV respectively, as determined by the Kubelka–Munk algorithm. The outcomes of frontier molecular orbitals, global reactivity descriptors, Mulliken, and molecular electrostatic potential surface by density functional theory calculations revealed high intramolecular charge transfer, good realistic stability, and high reactiveness of EOCD. The hydrazone EOCD exhibited higher hyperpolarizability (18.248 × 10−30 esu) in comparison to urea. Antioxidant test results indicated that EOCD showed significant antioxidant activity (p < 0.05), as determined by the DPPH radical scavenging assay. The newly synthesized EOCD showed no antifungal activity against Aspergillus flavus. Additionally, the EOCD showed good antibacterial activity against Escherichia coli and Bacillus subtilis.

Enhanced femtosecond nonlinear optical response in Mn-doped Cs2AgInCl6 nanocrystals.

Lead-free halide double perovskite nanocrystals (DPNCs) are emerging materials, recently explored as potential candidates in light-emitting, photovoltaic, and other optoelectronic applications. This Letter reveals unusual photophysical phenomena and nonlinear optical (NLO) properties of Mn-doped Cs2AgInCl6 nanocrystals (NCs) via temperature-dependent photoluminescence (PL) and femtosecond Z-scan measurements. The PL emission measurements suggest that self-trapped excitons (STEs) are present, and more than one STE state is possible for this doped double perovskite. We observed enhanced NLO coefficients, owing to the improved crystallinity arising from the Mn doping. From the closed aperture Z-scan data, we have calculated two fundamental parameters, Kane energy (29 eV) and exciton reduced mass (0.22m0). We further obtained the optical limiting onset (1.84 mJ/cm2) and figure of merit as a proof-of-concept application to demonstrate the potential in optical limiting and optical switching applications. Highlighting the self-trapped excitonic emission and NLO applications, the multifunctionality of this material system is demonstrated. This investigation provides an avenue to design novel photonic and nonlinear optoelectronic devices.