An 8-Connected Chiral Lanthanide Metal-organic Framework Constructed from Naturally Camphoric Acid:Crystal Structure,Vibrational Circular Dichroism Spectroscopy and Second-order Nonlinear Optical Effect

A chiral lanthanide metal-organic framework based on enantiopure camphoric acid （D-H2cam）, [Nd3（D-cam）8（H2O）4Cl]n （1）, has been synthesized and characterized by single-crystal X-ray structural analysis, elemental analysis, IR, thermal gravimetric, and X-ray powder diffraction. Crystal data for the title compound are as follows： orthorhombic system, space group P212121 with a = 13.8287（7）, b = 14.0715（7）, c = 25.7403（12） A^°, V = 5008.8（4） A^°3, Mr = 1333.08, Z = 4, F（000） = 2644, Dc = 1.768 g/cm^3, μ（MoKα） = 3.189 mm^-1, the final R = 0.0351 and wR = 0.0814 （I 〉 2σ（I））. Compound 1 displays an 8-connected bcu topology 3D framework and hydrogen-bonding interactions stabilize the solid-state structure. The vibrational circular dichroism （VCD） spectrum and second-order nonlinear optical effect of compound 1 have been studied in the solid state.

Crystal Structure of (γ-CH_3C_5H_4N)_2Zn(S_2C_2(CN)_2)and the Second Harmonic Effect

The title compound (γ-CH3C5H4N)2Zn(S2C2 (CN )2 ) crystallizes in theorthorhombic system, space group C2221, with a= 10. 069 (2), b= 14. 629 (4), c=11. 923(4) A, V= 1756. 2(3) A3, Dc= 1. 48g/cm3, Z=4, Mr= 391.81. λ(MoKa)= 0. 71069 A, μ= 16. 6 cm--l, F(000) = 800, final R= 0. 055 and Rw= 0. 066 for.1481 observed reflections with I≥3σ(I). In the (γ-CH3C5H4N)2Zn(S2C2(CN)2 ) complex, Zn2+ is coordinated by two nitrogen atoms from two 4--methylpyridine ligands andtwo sulfur atoms from maleonitriledithiol ligand. The powder tests show a frequencydoubling effect 2. 4 times as great as KH2PO4, which is in consistency with theoreticalcalculations

Optical super-resolution effect induced by nonlinear characteristics of graphene oxide films

In this work, we focus on the optical super-resolution effect induced by strong nonlinear saturation absorption(NSA) of graphene oxide(GO) membranes. The third-order optical nonlinearities are characterized by the canonical Z-scan technique under femtosecond laser(wavelength: 800 nm, pulse width: 100 fs) excitation. Through controlling the applied femtosecond laser energy, NSA of the GO films can be tuned continuously. The GO film is placed at the focal plane as a unique amplitude filter to improve the resolution of the focused field. A multi-layer system model is proposed to present the generation of a deep sub-wavelength spot associated with the nonlinearity of GO films. Moreover, the parameter conditions to achieve the best resolution(~λ/6) are determined entirely. The demonstrated results here are useful for high density optical recoding and storage, nanolithography, and super-resolution optical imaging.

Bioapplications Manipulated by AIEgens with Nonlinear Optical Effect

The modern medicine requires precise diagnostic techniques while the fluorescent imaging shows great potential in such applications due to its excellent sensitivity and high resolution.However,conducting fluorescent imaging in deep-tissue is not so easy because most luminogens show short-wavelength excitation,which may undergo severe light scattering by the bio-tissue.The marriage of fluorescent imaging with nonlinear optical(NLO)effect can alleviate such adverse effects by utilizing NIR laser to reduce light scattering.On the other hand,scientists are enthusiastic in pursuing luminescent materials,which can match well with NLO application.Aggregation-induced emission(AIE)materials exhibit huge advantages in such aspect not only because of its high luminescent efficiency in aggregate state but also due to its excellent photo-stability(a key factor to meet laser application because of its ultrahigh energy density).Inspired by this,many interesting and meaningful works have sprung up based on AIE luminogens with NLO effect in recent years,and for such reason,it motivates us to summarize them to give a systematic presentation.Here,we first give a brief introduction of the principle of NLO effect.Secondly,the strategies for improving the NLO effect of AIE materials,such as increasing molecular conjugation,introduction of donor-acceptor effect,induction of centrally asymmetric array of AIE molecules in crystals and introduction of intermolecular interactions are clarified.In the final part,we also present the multiple applications of AIEgens with NLO effect in cell imaging,deep-tissue tumor and brain blood vessel imaging and photodynamic therapy.We believe,with this review,the topic will attract more attention from the scientists in multi-science field to accelerate the development of AIE materials in biomedical applications.

Intra-Channel Nonlinear Effect on Optical PPM Pulse Transmission

PPM encoded Gaussian pulse sequence shows more immunity than non-PPM schemes on optical fiber intra-channel nonlinearity and demonstrated by a numerical study of IXPM and IFWM effects deploying on 100Gb/s single channelsystem.

Recent Issues on Nonlinear Effects in Optical Fibers

This talk will discuss the types of optical signal degradation due to fiber nonlinearity and review recently invented fibers for suppressing the effects. It also introduces efficiency of highly nonlinear fibers and their applications to nonlinear signal processing.

Correction of walk-off-induced wavefront distortion for continuous-wave laser

We theoretically and experimentally investigate the wave front distortion in critically phase-matched continuouswave（CW） second harmonic generation（SHG）.Due to the walk-off effect in the nonlinear crystal,the generated second harmonic is extremely elliptical and quite non-Gaussian,which causes a very low matching and coupling efficiency in experiment.Cylindrical lenses and walk-off compensating crystals are adopted to correct distorted wave fronts,and obtain a good TEM00 mode efficiently.Theoretically,we simulate the correction effect of 266-nm laser generated with SHG.The experiment results accord well with the theoretical simulation and an above 80% TEM_（00） component is obtained for 266-nm continuous-wave laser with a 4.8？-walk-off angle in beta barium borate（BBO） crystal.

Effects of gain nonlinearities in an optically injected gain lever semiconductor laser

The effects of gain compression on the modulation dynamics of an optically injected gain lever semiconductor laser are studied. Calculations reveal that the gain compression is not necessarily a drawback affecting the laser dynamics. With a practical injection strength, a high gain lever effect and a moderate compression value allow us to theoretically predict a modulation bandwidth four times higher than the free-running one without a gain lever,which is of paramount importance for the development of directly modulated broadband optical sources compatible with short-reach communication links.

Optical third-harmonic generation of spherical quantum dots under inversely quadratic Hellmann plus inversely quadratic potential

The third-harmonic generation(THG)coefficient for a spherical quantum dot system with inversely quadratic Hellmann plus inversely quadratic potential is investigated theoretically,considering the regulation of quantum size,confinement potential depth and the external environment.The numerical simulation results indicate that the THG coefficient can reach the order of 10~(-12)m~2V~(-2),which strongly relies on the tunable factor,with its resonant peak experiencing a redshift or blueshift.Interestingly,the effect of temperature on the THG coefficient in terms of peak location and size is consistent with the quantum dot radius but contrasts with the hydrostatic pressure.Thus,it is crucial to focus on the influence of internal and external parameters on nonlinear optical effects,and to implement the theory in practical experiments and the manufacture of optoelectronic devices.

Monolayer-molybdenum-disulfide-based nano-optomechanical transistor and tunable nonlinear responses

Atomically thin two-dimensional semiconductor nanomaterials have attained considerable attention currently. Here, we present a nano-optomechanical system based on a suspended monolayer molybdenum disulfide （MoS2）. The linear and nonlinear coherent optical properties of this system, and the phenomenon ofphonon-induced transparency are demonstrated. The transmission of the probe field can be manipulated by the power of a second ‘gating＇ （pump） field, which indicates a promising candidate for an optical transistor. We further study the nonlinear effect of the system, and the optical Kerr effect of the monolayer MoS2 resonator can be regulated under different parameter regimes. This scheme proposed here may indicate potential chip-scale applications of monolayer MoS2 resonator in quantum information with the currently popular pump-probe technology.

Controlled growth of plasmonic heterostructures and their applications

Plasmonic nanocrystals with unique properties have been extensively studied in the past decades.A combination of plasmonic materials with other characteristic materials of metals and semiconductors leads to properties far beyond single-component materials and excellent performances in many optical-related applications.In this review,we summarize the recent advances in the controlled growth of plasmonic heterostructures with a specific composition,morphology,size,and structural symmetry.Plasmonenhanced properties of the heterostructures and their excellent performances in applications are also discussed.The synthesis strategies and the intriguing properties of the plasmonic heterostructures provide great opportunity for applications in plasmon-enhanced nonlinear optics,optical spectroscopy,photocatalysis,solar energy conversion,and so on.