Second-harmonic generation(SHG)is a fundamental nonlinear optical process widely used in photonics;however,it is strictly forbidden in the bulk of centrosymmetric materials due to their inversion symmetry.Nevertheless...Second-harmonic generation(SHG)is a fundamental nonlinear optical process widely used in photonics;however,it is strictly forbidden in the bulk of centrosymmetric materials due to their inversion symmetry.Nevertheless,applying an external electric field breaks this inversion symmetry.It induces an effective second-order nonlinear response known as the electric-field-induced second-harmonic generation(EFISH)effect.This mechanism enables SHG in centrosymmetric media and provides a effective mechanism for electrically tunable nonlinear nanophotonics.Here,we present a comprehensive overview of the EFISH effect,covering the fundamentals,various material platforms(including bulk semiconductor crystals,ferroelectrics,van der Waals materials,and polymers),as well as diverse strategies for electric field engineering.We distinguish EFISH from related effects including currentinduced SHG and the quantum-confined Stark effect,and highlight emerging applications of EFISH in tunable photonic devices,carrier dynamics probing,and nonlinear optical modulation across optical,electronic,and THz regimes.Finally,we outline key challenges and prospects for the future development of electrically controlled nonlinear optical systems.展开更多
After tentative ring-opening cross metathesis （ROCM） of endo-bicyclo[3.2.0]hept-6-en-3-yl 4-bromobenzoate with PhCH = CH2 initiated by （Cy3P）2Cl2Ru = CHPh in CH2Cl2, ring-opening metathesis polymerization （ROMP）...After tentative ring-opening cross metathesis （ROCM） of endo-bicyclo[3.2.0]hept-6-en-3-yl 4-bromobenzoate with PhCH = CH2 initiated by （Cy3P）2Cl2Ru = CHPh in CH2Cl2, ring-opening metathesis polymerization （ROMP） of a series of endo-bicyclo[3.2.0]hept-6-en-3-yl benzoates was achieved under the same conditions, furnishing a variety of the corresponding polymers. Then some of them were selected to hydrogenate the C=C double bonds in their backbone with p-tosylhydrazide, affording saturated and thus more flexible polymers. All of these polymers were well characterized by spectroscopic means including GPC, UV-Vis, NMR and IR, based on which the tacticity of these polymers was investigated together with nonlinear optical （electric-field-induced second-harmonic generation, EFISH）） analysis.展开更多
Nonlinear optical materials are one of the key research objects in the field of optics, which mainly research the nonlinear effects of the interaction between luminesce and matter. Compared with inorganic nonlinear op...Nonlinear optical materials are one of the key research objects in the field of optics, which mainly research the nonlinear effects of the interaction between luminesce and matter. Compared with inorganic nonlinear optical materials, organic nonlinear materials have outstanding advantages: strong adaptability, high flexibility, low cost, easy modification and damage resistance. In this review, the electric field induced second harmonic generation (EFISH) experimental technology is used to measure and research the nonlinearity of iridium metal complexes. And because of its structural diversity, people can design molecules according to their needs to get the best nonlinear optical response. Organic molecules with large nonlinear coefficients should have the following characteristics: asymmetric charge distribution, the delocalized nature of π electrons, and easy polarization by external electric fields, and a large π conjugated system. In recent years, metal organic compounds have become a leader in the field of optics, mainly because of their very good nonlinear optical properties. In the future, people will do more investigation on the nonlinearity of metal organic complexes. Researchers have shown great interest in iridium metal organic complexes due in particular to their attractive stability and nonlinear activity. This review mainly studies the nonlinear principle, performance test and Measurement of nonlinearity of iridium metal complexes. The nonlinear properties of other metal-metal organic complexes will not be discussed.展开更多
基金supported by Priority 2030 FederalAcademic Leadership ProgramBASIS Foundation
文摘Second-harmonic generation(SHG)is a fundamental nonlinear optical process widely used in photonics;however,it is strictly forbidden in the bulk of centrosymmetric materials due to their inversion symmetry.Nevertheless,applying an external electric field breaks this inversion symmetry.It induces an effective second-order nonlinear response known as the electric-field-induced second-harmonic generation(EFISH)effect.This mechanism enables SHG in centrosymmetric media and provides a effective mechanism for electrically tunable nonlinear nanophotonics.Here,we present a comprehensive overview of the EFISH effect,covering the fundamentals,various material platforms(including bulk semiconductor crystals,ferroelectrics,van der Waals materials,and polymers),as well as diverse strategies for electric field engineering.We distinguish EFISH from related effects including currentinduced SHG and the quantum-confined Stark effect,and highlight emerging applications of EFISH in tunable photonic devices,carrier dynamics probing,and nonlinear optical modulation across optical,electronic,and THz regimes.Finally,we outline key challenges and prospects for the future development of electrically controlled nonlinear optical systems.
基金supported by the National Natural Science Foundation of China(No.20902002)the Introduced Talents from Anhui University of Technology and Science(No.2008YQ009)
文摘After tentative ring-opening cross metathesis （ROCM） of endo-bicyclo[3.2.0]hept-6-en-3-yl 4-bromobenzoate with PhCH = CH2 initiated by （Cy3P）2Cl2Ru = CHPh in CH2Cl2, ring-opening metathesis polymerization （ROMP） of a series of endo-bicyclo[3.2.0]hept-6-en-3-yl benzoates was achieved under the same conditions, furnishing a variety of the corresponding polymers. Then some of them were selected to hydrogenate the C=C double bonds in their backbone with p-tosylhydrazide, affording saturated and thus more flexible polymers. All of these polymers were well characterized by spectroscopic means including GPC, UV-Vis, NMR and IR, based on which the tacticity of these polymers was investigated together with nonlinear optical （electric-field-induced second-harmonic generation, EFISH）） analysis.
文摘Nonlinear optical materials are one of the key research objects in the field of optics, which mainly research the nonlinear effects of the interaction between luminesce and matter. Compared with inorganic nonlinear optical materials, organic nonlinear materials have outstanding advantages: strong adaptability, high flexibility, low cost, easy modification and damage resistance. In this review, the electric field induced second harmonic generation (EFISH) experimental technology is used to measure and research the nonlinearity of iridium metal complexes. And because of its structural diversity, people can design molecules according to their needs to get the best nonlinear optical response. Organic molecules with large nonlinear coefficients should have the following characteristics: asymmetric charge distribution, the delocalized nature of π electrons, and easy polarization by external electric fields, and a large π conjugated system. In recent years, metal organic compounds have become a leader in the field of optics, mainly because of their very good nonlinear optical properties. In the future, people will do more investigation on the nonlinearity of metal organic complexes. Researchers have shown great interest in iridium metal organic complexes due in particular to their attractive stability and nonlinear activity. This review mainly studies the nonlinear principle, performance test and Measurement of nonlinearity of iridium metal complexes. The nonlinear properties of other metal-metal organic complexes will not be discussed.
