Dependence of the periodically poled nonlinear-optical lithium niobate (PPLN) crystal temperature on laser power in the course of laser frequency conversion was measured using piezoelectric resonance. Crystal’s tempe...Dependence of the periodically poled nonlinear-optical lithium niobate (PPLN) crystal temperature on laser power in the course of laser frequency conversion was measured using piezoelectric resonance. Crystal’s temperature tuning curves are precisely measured using concept of the equivalent temperature. Both optical absorption and heat transfer coefficients of the crystal are measured employing kinetics of the crystal equivalent temperature.展开更多
Deep-ultraviolet(DUV,λ<200 nm)nonlinear-optical(NLO)crystals play a pivotal role in modern laser science and technology.Metal phosphates have been considered as fascinating candidates for DUV NLO crystal material....Deep-ultraviolet(DUV,λ<200 nm)nonlinear-optical(NLO)crystals play a pivotal role in modern laser science and technology.Metal phosphates have been considered as fascinating candidates for DUV NLO crystal material.However,how to generate both strong second-harmonic-generation(SHG)response and large birefringence for promising DUV NLO metal phosphates is a long-standing issue.Herein,a new DUV NLO metal phosphate,BaNa_(2)[PO_(3)(OH)]_(2),was successfully synthesized,which features a two-dimensional[NaPO_(3)(OH)]_(∞)alveolate layer alternately connected by highly asymmetric[PO_(3)(OH)]groups and NaO5 triangular bipyramids.BaNa_(2)[PO_(3)(OH)]_(2)can realize a good balance of DUV nonlinear properties covering short UV absorption edge less than 190 nm,strong SHG response with the magnitude of~1.2×benchmark KH_(2)PO_(4)(KDP),and the largest birefringence with the experimental value of 0.064@590±3 nm in reported alkaline/alkaline-earth metal phosphates,producing the shortest phase-matching output down to the wavelength of 164 nm.These research results show that BaNa_(2)[PO_(3)(OH)]_(2)crystal is a potential DUV NLO crystal material.展开更多
We calculate structural, electronic properties and chemical bonding of borate Li4CaB2O6 under high pressure by means of the local density-functional pseudopotential approach. The equilibrium lattice constants, density...We calculate structural, electronic properties and chemical bonding of borate Li4CaB2O6 under high pressure by means of the local density-functional pseudopotential approach. The equilibrium lattice constants, density of states, Mulliken population, bond lengths, bond angles as well as the pressure dependence of the band gap are presented. Analysis of the simulated high pressure band structure suggests that borate Li4CaB2O6 can be used as the semi-conductor optical material. Based on the Mulliken population analysis, it is found that the electron transfer of the Li atom is very different from that of other atoms in the studied range of high pressures. The charge populations of the Li atom decrease with the pressure up to 60 GPa, then increase with the pressure.展开更多
Two new two-photon absorption （TPA） molecules, named SK-G1 and NT-G1, are synthesized and the photo- physical characteristics are investigated by using linear absorption spectra, one-photon fluorescence spectra and ...Two new two-photon absorption （TPA） molecules, named SK-G1 and NT-G1, are synthesized and the photo- physical characteristics are investigated by using linear absorption spectra, one-photon fluorescence spectra and two-photon excited fluorescence spectra. Both the compounds exhibit TPA properties, and the TPA values determined by z-scan measurement are 10 GM and 39 GM for SK-G1 and NT-G1, respectively, at wavelength 80Ohm. Time-resolved spectroscopic techniques are employed to further explore the excited state dynamics of NT-G l with larger TPA cross section. The research results show that there is an ultrafast intraband energy transfer process （about 3ps） before the formation of charge transfer state with a relatively long lifetime.展开更多
Organic-inorganic hybrid glass-ceramics have received ever-growing attention as nascent research hotspots due to their extraordinary optical properties,e.g.,nonlinear optical response,whereas the documented hybrid gla...Organic-inorganic hybrid glass-ceramics have received ever-growing attention as nascent research hotspots due to their extraordinary optical properties,e.g.,nonlinear optical response,whereas the documented hybrid glass-ceramics are associated with underlying steric effects of quaternary phosphonium cations with a large triphenylphosphanyl group(-PPh_(3)).In contrast,numerous hybrid salts based on more easily accessible quaternary ammonium cations have been reported,but they have rarely been fabricated as glass-ceramics or even glasses.Herein,we present four hybrid quaternary ammonium salts,(R_(3)NBn)[FeCl_(4)](Bn=benzyl;R=Me for 1,Et for 2,Pr for 3,and Bu for 4,respectively),which belong to space groups P-1,Pbca,Pna2_(1),and P3_(1),respectively,and undergo intriguing solid-liquid phase transitions at melting temperatures of 355,356,368,and 330 K,respectively.Unlike 1-3 revealing fast recrystallization during the subsequent cooling processes,4 with the longer and more flexible butyl groups shows a much slower recrystallization rate due to the reduced attractive interactions between organic cations and inorganic anions and the increased repulsion from the adjacent cations.As a result,4 exhibits thermally-induced reversible crystal-liquid-glass-crystal transformations with vitrified temperature of 248 K and recrystallized on-set temperature of 286 K.Strikingly,a glass-ceramic thin film of 4 with inner polar micro-crystals embedded in glass was manufactured under ambient conditions.This thin film unfolds great enhancement of second-harmonic generation response,being approximately 12 times larger than its poly-crystalline form,without any poling treatments.The investigation provides the first access to polar glass-ceramic in hybrid quaternary ammonium salts and offers promising insights for designing glass-ceramics in diverse hybrid salts.展开更多
文摘Dependence of the periodically poled nonlinear-optical lithium niobate (PPLN) crystal temperature on laser power in the course of laser frequency conversion was measured using piezoelectric resonance. Crystal’s temperature tuning curves are precisely measured using concept of the equivalent temperature. Both optical absorption and heat transfer coefficients of the crystal are measured employing kinetics of the crystal equivalent temperature.
文摘Deep-ultraviolet(DUV,λ<200 nm)nonlinear-optical(NLO)crystals play a pivotal role in modern laser science and technology.Metal phosphates have been considered as fascinating candidates for DUV NLO crystal material.However,how to generate both strong second-harmonic-generation(SHG)response and large birefringence for promising DUV NLO metal phosphates is a long-standing issue.Herein,a new DUV NLO metal phosphate,BaNa_(2)[PO_(3)(OH)]_(2),was successfully synthesized,which features a two-dimensional[NaPO_(3)(OH)]_(∞)alveolate layer alternately connected by highly asymmetric[PO_(3)(OH)]groups and NaO5 triangular bipyramids.BaNa_(2)[PO_(3)(OH)]_(2)can realize a good balance of DUV nonlinear properties covering short UV absorption edge less than 190 nm,strong SHG response with the magnitude of~1.2×benchmark KH_(2)PO_(4)(KDP),and the largest birefringence with the experimental value of 0.064@590±3 nm in reported alkaline/alkaline-earth metal phosphates,producing the shortest phase-matching output down to the wavelength of 164 nm.These research results show that BaNa_(2)[PO_(3)(OH)]_(2)crystal is a potential DUV NLO crystal material.
基金Supported by the National Natural Science Foundation of China under Grant No 10676025.
文摘We calculate structural, electronic properties and chemical bonding of borate Li4CaB2O6 under high pressure by means of the local density-functional pseudopotential approach. The equilibrium lattice constants, density of states, Mulliken population, bond lengths, bond angles as well as the pressure dependence of the band gap are presented. Analysis of the simulated high pressure band structure suggests that borate Li4CaB2O6 can be used as the semi-conductor optical material. Based on the Mulliken population analysis, it is found that the electron transfer of the Li atom is very different from that of other atoms in the studied range of high pressures. The charge populations of the Li atom decrease with the pressure up to 60 GPa, then increase with the pressure.
基金Supported the Leading Academic Discipline Programme （T0104）, the National Natural Science Foundation of China under Grant Nos 10374020 and 10674031, and the Seventh Graduate Students Innovation Foundation of Fudan University.
文摘Two new two-photon absorption （TPA） molecules, named SK-G1 and NT-G1, are synthesized and the photo- physical characteristics are investigated by using linear absorption spectra, one-photon fluorescence spectra and two-photon excited fluorescence spectra. Both the compounds exhibit TPA properties, and the TPA values determined by z-scan measurement are 10 GM and 39 GM for SK-G1 and NT-G1, respectively, at wavelength 80Ohm. Time-resolved spectroscopic techniques are employed to further explore the excited state dynamics of NT-G l with larger TPA cross section. The research results show that there is an ultrafast intraband energy transfer process （about 3ps） before the formation of charge transfer state with a relatively long lifetime.
基金supported by the National Natural Science Foundation of China(22071273,U2341287,21821003)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23lgzy001).
文摘Organic-inorganic hybrid glass-ceramics have received ever-growing attention as nascent research hotspots due to their extraordinary optical properties,e.g.,nonlinear optical response,whereas the documented hybrid glass-ceramics are associated with underlying steric effects of quaternary phosphonium cations with a large triphenylphosphanyl group(-PPh_(3)).In contrast,numerous hybrid salts based on more easily accessible quaternary ammonium cations have been reported,but they have rarely been fabricated as glass-ceramics or even glasses.Herein,we present four hybrid quaternary ammonium salts,(R_(3)NBn)[FeCl_(4)](Bn=benzyl;R=Me for 1,Et for 2,Pr for 3,and Bu for 4,respectively),which belong to space groups P-1,Pbca,Pna2_(1),and P3_(1),respectively,and undergo intriguing solid-liquid phase transitions at melting temperatures of 355,356,368,and 330 K,respectively.Unlike 1-3 revealing fast recrystallization during the subsequent cooling processes,4 with the longer and more flexible butyl groups shows a much slower recrystallization rate due to the reduced attractive interactions between organic cations and inorganic anions and the increased repulsion from the adjacent cations.As a result,4 exhibits thermally-induced reversible crystal-liquid-glass-crystal transformations with vitrified temperature of 248 K and recrystallized on-set temperature of 286 K.Strikingly,a glass-ceramic thin film of 4 with inner polar micro-crystals embedded in glass was manufactured under ambient conditions.This thin film unfolds great enhancement of second-harmonic generation response,being approximately 12 times larger than its poly-crystalline form,without any poling treatments.The investigation provides the first access to polar glass-ceramic in hybrid quaternary ammonium salts and offers promising insights for designing glass-ceramics in diverse hybrid salts.
