Maker Fringe Method Research Articles

High nonlinear optical efficiency in zinc(II) and copper(I) stilbene based iminopyridine complexes: Absorption, emission analysis and advanced characterization

The novelty of this work lies in the comprehensive studies of the spectroscopic and third-order nonlinear optical properties of zinc(II) and copper(I) stilbene based iminopyridine complexes. Our previous work involved the synthesis as well as the characterization of both the free ligand and these its corresponding metal complexes and conducting quantum chemical calculations on their molecular orbitals, shedding light on their charge transfer and π-π* interactions. This makes these materials promising models for supramolecular assemblies. Thin films, obtained using the spin coating method, are characterized using Atomic Force Microscopy and Ellipsometry methods. These techniques provide valuable information about the physical properties of the layers, such as homogeneity, roughness and linear refractive index. Moreover, we present spectroscopic analysis that involve the absorption and emission of light, along with the decay time of photoluminescence in the thin films. Through advanced techniques like the Maker fringe method for third harmonic generation and the Z-scan method for recording nonlinear absorption and refraction, we demonstrate the high nonlinear optical efficiency of these complexes. This study presents how specific structural elements impacts tailoring in the enhancement of the NLO properties of these complexes. These findings underscore the potential of zinc(II) and copper(I) stilbene based iminopyridine complexes in nonlinear optics and photonics applications.

Determination of nonlinear optical coefficients and efficient type-II second-harmonic-generation for TmCOB crystals

By Maker Fringe (MF) method, all of the nonlinear optical (NLO) coefficients including d11, d12, d13, d31, d32 and d33 of TmCa4O(BO3)3 (TmCOB) crystals were measured to be 0.19, 0.26, −0.61, −0.30, 1.66 and −1.25 pm/V, respectively. Based on which, the second-harmonic-generation (SHG) phase-matching (PM) characteristics of TmCOB crystals in two-dimensional principal planes and three-dimensional non-principal planes (space) were theoretically calculated, such as PM tuning curves, distribution of effective NLO coefficient (deff), beam walk-off angle, and angular acceptance bandwidth. At the fundamental waves of 1064 nm, the type-II optimal PM angles with largest deff for principal planes and space were decided to be (52.8°, 90.0°) (deff = 0.24 pm/V) and (118.0°, 77.2°) (deff = 0.35 pm/V), respectively. The type-II SHG of TmCOB crystals was found to present large acceptance angle bandwidth (~2–12 times of type-I values) and small beam walk-off angle (~0.2–0.4 times of type-I values). At a high input energy of 6.89 mJ (35 ps, 10 Hz, 1064 nm), the SHG transformation efficiency for an uncoated TmCOB crystal sample cut along type-II optimal angle (118.0°, 77.2°) with 12 mm in length was measured to be 55.9%, which achieved the same conversion efficiency grade as type-I optimal PM.

Crystal Growth and Linear and Nonlinear Optical Properties of KIO3·Te(OH)6

A single crystal of the nonlinear optical material KIO3·Te(OH)6 (KTI) with dimensions of 37 × 7 × 5 mm3 was successfully grown at room temperature by slow evaporation. Linear and nonlinear optical measurements were performed on these crystals. Rocking curve measurements indicate that the single crystal is of high quality with a full width at half-maximum (fwhm) of 0.023° (82 arcseconds) from the (010) reflection. Refractive index measurements revealed a birefringence of 0.0545 @ 1064 nm. Through the refractive index measurements and the fitted Sellmeier equations, we determined the Type I and Type II phase-matching wavelength ranges. KTI is Type I (Type II) phase-matchable with a fundamental wavelength range from 674–3266 nm (880–2260 nm). Powder second-harmonic generation (SHG) measurements indicate an SHG intensity of 1.2× KH2PO4 (KDP). SHG coefficients were determined by the Maker fringe method on cut and polished (100) and (010) single crystal wafers. The d31 = 0.24 pm/V and d32 = 0.73 pm/V were deter...

Crystal growth, crystal structure, vibrational spectroscopy, linear and nonlinear optical properties of guanidinium phosphates

Of the three guanidinium phosphates GuH2PO4 (space group P21/c), Gu2HPO4·H2O (space group P4¯21c) and Gu3PO4· 32 H2O (space group Cc) crystal structures and a vibrational spectroscopy study are presented. Large single crystals of GuH2PO4 and Gu2HPO4·H2O are grown. Refractive indices and their dispersion in the wavelength range 365 nm – 1083 nm are determined and used for the analysis of phase matching conditions for collinear SHG in the case of the non-centrosymmetric crystals of Gu2HPO4·H2O. The crystals are not phase-matchable within their transmission range. Both independent components of the SHG tensor of Gu2HPO4·H2O, determined by the Maker fringe method, are given, with d14 = 0.23 pm/V and d36 = 0.22 pm/V. In addition, the thermal stability and the anisotropy of thermal expansion of GuH2PO4 and Gu2HPO4·H2O is reported.

Optical nonlinear and electro‐optical coefficients in bulk aluminium nitride single crystals

Bulk aluminium nitride single crystals grown by physical vapour transport were characterised for their nonlinear optical properties. The two independent nonzero optical nonlinear coefficients were determined by the Maker Fringe method, with a LiNbO3 plate as a reference. At a wavelength of 1030 nm, the measured coefficient |d33| = (4.3 ± 0.3) pm V−1 and |d31| = |d33|/(45 ± 5). Michelson interferometer was used to measure two unclamped electro‐optic coefficients to give r33 = (1.16 ± 0.13) pm V−1 and r13 = (0.11 ± 0.02) pm V−1 at a wavelength of 633 nm. By calculating the dispersion relation for d33, we show that AlN is a very promising material for quasi phase‐matched frequency conversion into UV.

Bulk second-harmonic generation from thermally evaporated indium selenide thin films.

We investigate bulk second-order nonlinear optical properties of amorphous indium selenide thin films fabricated by thermal evaporation. Such films are shown to exhibit strong and photostable second-harmonic generation (SHG). We report strong thickness dependence of the second-harmonic signals as characterized by the Maker-fringe method. The absolute value of the nonlinear susceptibility tensor of the film is addressed by analyzing the interference of SHG signals from the film and the glass substrate. The value of the joint non-diagonal component of the susceptibility is found to be 4 pm/V, which is comparable to that of widely used second-order nonlinear materials.

The optimal phase-matching angles for third harmonic generation of low symmetry nonlinear optical crystal La2CaB10O19

The signs of nonlinear optical (NLO) coefficients of La2CaB10O19 (LCB) crystal were determined by Maker fringe method and phase-matching method. Compared with d22, the signs of d21 and d23 are found by Maker fringe method to be negative and positive, respectively, and the sign of d14 is found to be positive by phase-matching method. Phase-matching angles for third harmonic generation (THG) in LCB crystal were calculated and verified by experiments. The distribution of effective NLO coefficient (deff) and the optimal phase-matching angles for THG with LCB crystal are determined for the first time, with optimal phase-matching angles of (48.7°, 72.5°) and (65.3°, 37.5°) for type-I and type-II THG, respectively. The results show that LCB is an excellent NLO crystal for THG application.

Third-order nonlinear optical characteristics of bulk film effect on regioregular poly(3-dodecylthiophene) thin films fabricated by the drop-casting method

We report the morphologies and the bulk film effect on regioregular poly(3-dodecylthiophene) [RR-P3DDT] thin films fabricated with different concentrations (0.1, 0.2, 0.4 wt%) by drop-casting method using chloroform as a solvent and fused quartz glass as substrate. The measured thicknesses of the films were 220, 340 and 600 nm. The thin films were characterized by UV–Vis spectra and X-ray diffraction. The surface morphology of the thin film (600 nm) was analyzed using atomic force microscopy. The third order nonlinear susceptibility characteristics of the films were measured using Maker fringes method. These films exhibit efficient THG bulk effect with a maximum χ3 value of 1.41 × 10−10 esu obtained for 0.4 wt% concentration of RR-P3DDT revealing that this material is potentially suited for fabricating optical limiters.

Germanosilicate glass–ceramics for non-linear optics

Glass samples in the GeO2·SiO2·Nb2O5·K2O system, with different K2O/Nb2O5 ratios, were prepared, and glass–ceramics were obtained by controlled crystallization. Characterization included density measurements (Archimedes’ method), differential thermal analysis, X-ray diffraction (XRD), and Raman and UV–Visible spectroscopies. Crystal volume fractions were estimated from density measurements, while XRD was used to estimate the crystal size, by the Scherrer formula. XRD and Raman data showed that a K2O/Nb2O5 ratio of 1 promoted the formation of the crystalline phase K3.8Nb5Ge3O20.4 and transparent glass–ceramics could be obtained with a crystalline fraction of 79 % and an average crystal size of 19 nm, while a K2O/Nb2O5 ratio of 2 promoted the formation of KNbO3 crystalline phase, and a translucent glass–ceramic was obtained with a crystalline fraction of 27 % and a crystal size of 14 nm. The Maker fringe method was used to compare the second-harmonic generation efficiency of the glass–ceramics with a Y-cut quartz reference.

Growth and nonlinear optical properties of K3B6O10Br crystal

Nonlinear optical (NLO) crystal K3B6O10Br with the size of 27×29 ×14mm3 was successfully grown by top seeded solution growth (TSSG) technique. Its second harmonic generation (SHG) coefficients were determined by Maker fringe method as: d22=1.23±0.01pm/V and d33=0.43±0.01pm/V. Its linear electro-optical (EO) coefficient γ22=0.81±0.06pm/V, which is usually employed in transverse modulation, was measured with polarimetric method.

Linear and Nonlinear Optical Properties of K3B6O10Br Single Crystal: Experiment and Calculation

The experimental and theoretical analysis of linear and nonlinear optical properties of K3B6O10Br (KBOB), with a moderate birefringence that is suitable for UV coherent light generation and optical parametric oscillators, is presented in detail. The second-order nonlinear optical coefficients were measured by the Maker fringe method and the refractive indices dispersion curves were deduced by the minimum deviation technique at 16 different monochromatic sources from UV to NIR, and then the type I and type II phase-matching curves of second, third, and fourth harmonic generation (SHG, THG, and FHG) were calculated. Moreover, the correlations of crystallographic and crystallophysical axes were determined. On the basis of the density functional theory (DFT), the first-principles calculations have been employed successfully to study the structural and electronic properties of KBOB. In addition, to gain further insight into the structure-property relationship, the SHG density method was adopted to analyze the origin of the nonlinear optical response of KBOB.

Linear and nonlinear optical properties of Na3La2(BO3)3 crystal

A 30×20×8 mm 3 Na 3 La 2 (BO 3 ) 3 crystal has been grown by the top-seeded solution growth method (TSSG) using Na 2 O–B 2 O 3 –NaF as flux. The refractive indices at thirteen wavelengths from 0.2537 to 2.325 μm were accurately measured by the minimum deviation method, and the Sellmeier equations were accordingly constructed. The nonlinear optical (NLO) coefficients were measured by the Maker fringe method, which gave results of d 31 =1.45 pm/V, d 32 =0.67 pm/V, and d 33 =−1.06 pm/V, respectively. For second-harmonic generation (SHG) of 1064 nm, the effective NLO coefficient ( d eff ) of type I phase-matching reaches the maximum value (1.44 pm/V) at the phase-matching angles θ =77.0°, ϕ =212.1°, which is larger than that of LiB 3 O 5 (LBO). First-principle calculations suggest that Na 3 La 2 (BO 3 ) 3 possesses two types of NLO-active atom groups, BO 3 group with π-orbital system and La-centered polyhedron with large polar displacement, of which the latter could be considered as a new type of NLO-active atom group. • The refrative index and NLO coefficient have been measured for the first time. • The maxium effective NLO coefficient is larger than that of LBO crystal. • The distorted rare earth cation-centered polyhedron is suggested as new NLO-active atom group.

Laser-induced, second-order optical susceptibilities of YAB:Cr3+ single crystals

Complex temperature studies of optically stimulated second harmonic generation (SHG) at 1064 nm for pulsed 10 ns Nd:YAG laser radiation under illumination of two coherent laser beams (at 1064 nm and its 532 nm second harmonic) were carried out by means of the Maker fringe method. The bicolour coherent process allowed detection of some additionally induced non-centrosymmetry. The effect was studied at different temperatures and experimental geometries in YAB:Cr3+ single crystals. We found that Cr3+ ions play a principal role in the observed effects. The output of optically stimulated SHG was generally non-spherical in the sequence profile, contrary to the traditional non-stimulated SHG. Moreover, we also established that the optimal conditions for obtaining SHG corresponded to the fundamental/writing beam intensities ratio 6:1. A specially performed control of the photo-thermal sample heating showed that the increase of temperature did not exceed 1.2 K, which allowed the influence of photo-thermal heating to be neglected. The optimal input–output laser geometry corresponded to s-p polarisation and to the angle of about 32° between the photo-inducing and fundamental beams. Additionally in the studied temperature range (77–295 K) there was observed an enhancement of the output second-order susceptibilities from 0.72 pm/V up to 1.02 pm/V.

Second-harmonic generation from electron beam deposited SiO films

It is demonstrated that as-grown e-beam deposited SiOx thin films on fused silica substrates show a second-order nonlinear response that is dependent on film thickness. Using a Maker fringes method the effective nonlinear coefficient for a SiO thin film is estimated to be comparable to that of crystalline quartz. Variation of process parameters has been used to investigate the origin of the nonlinear response. The second-harmonic signal is very sensitive to annealing of the film and can be totally removed by annealing at a few hundred degrees. It is also demonstrated that a retarding grid that traps charged particles between the crucible and the sample reduces the nonlinear signal from a SiO thin film significantly. It is suggested that oriented dipoles arise during deposition due to a negatively charged film from oxygen ions, thus, resulting in a non-centrosymmetric film. Finally, using e-beam lithography, well-defined nonlinear 2D structures can be synthesized, thus opening the door to a new and practical way to create nonlinear structures for planar waveguide technology.

Measurement of second-order nonlinear optical coefficients of BaMgF_4

The three independent second-order nonlinear optical coefficients of BaMgF4 are determined by the Maker fringe method with a nanosecond pulsed Nd:YAG laser at 1064 nm wavelength. All the results are relative to the reference crystal congruent LiNbO3. The largest element in a second-order nonlinear optical matrix of BaMgF4 is d32, with the value of 0.36 pm/V.

Second-Harmonic Generation of the Chalcogenide Amorphous Film by Electron Beam Irradiation

PLD(pulsed laser deposition) method was used to prepare amorphous GeS2-Ga2S3-CdS chalcogenide film. Obvious SHG(second harmonic generation) was observed in electron beam irradiated film by Maker fringe method. According to Raman spectra, we discussed the mechanism of SHG and ascribed the origination of SHG to the local electric field generation under electron beam and uneven charge distribution. With the increase of accelerating voltage and the extension of irradiation time, the SHG intensity increased and reached the maximum, which is due to the enhancement of breakage of glassy isotropy with gradually increased incident electron energy and the finite population of electric dipoles leading to the saturation of SH intensity.

Preparation and Second Harmonic Generation of CdS Doped Lead Silicate Glasses

CdS doped lead silicate glasses were prepared with the conventional fusion method. The effects of the ZnO/CdS ratio and the content of CdS on the preparation of CdS doped glasses were both studied. The crystallization process of CdS nanocrystals was investigated by X-ray diffractometry and scanning electron microscopy. Utilizing the Maker fringe method, Second harmonic generation (SHG) was observed from CdS doped glasses without any poling procedures. The SH intensity gets enhanced by increasing the heat-treatment temperature and prolonging the heat-treatment duration.

Significant Effect of Bromo Substituents on Nonlinear Optical Properties of Polymer and Chromophores

Four chromophores containing bromo substituents, a ployimide with bromo-containing chromophores, four reference functional polyimides, and fourteen reference chromophores were synthesized for studying effect of bromo substituents on nonlinear optical (NLO) properties of materials and chromophores. The results of hyper-Rayleigh scattering and UV-vis spectra show that static first molecular hyperpolarizability (beta(0)) values of bromo-containing chromophores are 1.24-5.75 times as beta(0) of the corresponding chloro-containing chromophores (Hammett constants sigma of chloro and bromo groups are same) without causing a visible shift of the absorption band to longer wavelength. UV-vis spectra and the results of Maker Fringe method show that the polyimide with chromophores containing bromo substituents exhibits a good optical transparency and a much higher macroscopic nonlinear optical coefficient (d(33) = 20.1 pm/V) than the reference polyimides containing nitro (d(33) = 9.6 pm/V) and cyano (d(33) = 8.9 pm/V) groups in spite of nitro and cyano groups being strong electron acceptors. d(33) of polyimide with chloro-containing chromophores is very small. Therefore, this paper suggests an effective strategy for improving the NLO properties of polymeric materials and chromophores without reducing optical transparency in designing NLO polymers and chromophores. On the basis of quantum chemistry calculations, the reasons of effect of bromo substituents on NLO properties of chromophores and materials were discussed.

Nonlinear Optical Properties and Ferroelectric Phase Transition of LaBGeO5

Optical second harmonic generation (SHG) and birefringence Δn of ferroelectric LaBGeO5 are measured as a function of temperature. Using the Maker-Fringe method, magnitudes of SHG tensor components and coherence lengths are determined. From the symmetry analysis of d tensor components, the space group of the paraelectric phase is assigned to be non-centrosymmetric P312. The critical index of the order parameter is determined to be 0.5 from the birefringence measurement in the vicinity of TC.

Optical Properties of Nanocrystalline Potassium Lithium Niobate in the Glass System (100-x) TeO2–x(1.5K2O–Li2O–2.5Nb2O5)

Optically clear glasses of various compositions in the system (100-x) TeO2-x(1.5K2O-Li2O-2.5Nb2O5) (2 < or = x < or = 12, in molar ratio) were prepared by the melt-quenching technique. The glassy nature of the as-quenched samples was established via differential scanning calorimetry (DSC). The amorphous and the crystalline nature of the as-quenched and heat-treated samples were confirmed by the X-ray powder diffraction and transmission electron microscopic (TEM) studies. Transparent glasses comprising potassium lithium niobate (K3Li2Nb5O15) microcrystallites on the surface and nanocrystallites within the glass were obtained by controlled heat-treatment of the as-quenched glasses just above the glass transition temperature (T(g)). The optical transmission spectra of these glasses and glass-crystal composites of various compositions were recorded in the 200-2500 nm wavelength range. Various optical parameters such as optical band gap, Urbach energy, refractive index were determined. Second order optical non-linearity was established in the heat-treated samples by employing the Maker-Fringe method.