Organic non-linear optical crystal diphenyl urea with molecular formula C13H12N2O was synthesized and grown successfully by slow evaporation solution growth technique. The single crystal X-ray diffraction (XRD) confir...Organic non-linear optical crystal diphenyl urea with molecular formula C13H12N2O was synthesized and grown successfully by slow evaporation solution growth technique. The single crystal X-ray diffraction (XRD) confirms that it crystallizes in orthorhombic crystal system with non-centrosymmetric space group Pna21. The various functional groups were identified qualitatively by Fourier transform-infra red (FT-IR) and FT-Raman techniques. The electron absorption spectrum was studied by UV-Vis spectrophotometer. Thermal behavior of the crystal was evidenced by thermogravimetric (TG) and differential scanning calorimetric (DSC) analyses. From DSC the melt ing point of the crystal is found to be 145°C. The existence of second harmonic generation (SHG) signal was evidenced using Kurtz Perry powder test and the efficiency of the crystal was found to be 0.64 times that of the standard KDP crystal.展开更多
Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However...Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.展开更多
The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex...The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex beams for various applications.In this work,the second harmonic(SH)optical vortex beams generated from nonlinear fork gratings under Gaussian beam illumination are numerically investigated.The far-field intensity and phase distributions,as well as the orbital angular momentum(OAM)spectra of the SH beams,are analyzed for different structural topological charges and diffraction orders.Results reveal that higher-order diffraction and larger structural topological charges lead to angular interference patterns and non-uniform intensity distributions,deviating from the standard vortex profile.To optimize the SH vortex quality,the effects of the fundamental wave beam waist,crystal thickness,and grating duty cycle are explored.It is shown that increasing the beam waist can effectively suppress diffraction order interference and improve the beam’s quality.This study provides theoretical guidance for enhancing the performance of nonlinear optical devices based on NPCs.展开更多
The memory behavior in liquid crystals(LCs)that is characterized by low cost,large area,high speed,and high-density memory has evolved from a mere scientific curiosity to a technology that is being applied in a variet...The memory behavior in liquid crystals(LCs)that is characterized by low cost,large area,high speed,and high-density memory has evolved from a mere scientific curiosity to a technology that is being applied in a variety of commodities.In this study,we utilized molybdenum disulfide(MoS_(2))nanoflakes as the vip in a homotropic LCs host to modulate the overall memory effect of the hybrid.It was found that the MoS₂nanoflakes within the LCs host formed agglomerates,which in turn resulted in an accelerated response of the hybrids to the external electric field.However,this process also resulted in a slight decrease in the threshold voltage.Additionally,it was observed that MoS₂nanoflakes in a LCs host tend to align homeotropically under an external electric field,thereby accelerating the refreshment of the memory behavior.The incorporation of a mass fraction of 0.1%2μm MoS₂nanoflakes into the LCs host was found to significantly reduce the refreshing memory behavior in the hybrid to 94.0 s under an external voltage of 5 V.These findings illustrate the efficacy of regulating the rate of memory behavior for a variety of potential applications.展开更多
Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)thr...Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)through the high-temperature solid-state spontaneous crystallization method.Different from the cubicα-Pb_(3)P_(2)S_(8),theβ-Pb_(3)P_(2)S_(8)crystallizes in the orthorhombic Pbcn space group.Notably,β-Pb_(3)P_(2)S_(8)shows a large band gap of 2.37 e V in lead-based chalcogenides,wide infrared transparent window(2.5-15μm),and excellent thermal stability.Importantly,the experimental birefringence shows the largest value of0.26@550 nm in chalcogenides,even larger than the commercialized oxide materials.The Barder charge analysis result indicates that the exceptional birefringence effect is mainly from the Pb^(2+)and S^(2-)in the[Pb S_n]polyhedrons.Meanwhile,the parallelly arranged polyhedral layers could improve the structural anisotropic.Therefore,this work supports a new method for designing chalcogenides with exceptional birefringence effect in the infrared region.展开更多
Ca_(12)Al_(14)O_(33)(C12A7)and Y_(0.02)Ca_(11.98)Al_(14)O_(33)(Y-C12A7)single crystals were grown by using the traveling-solvent floating zone(TSFZ)method.The temperature was increased to avoid the bubbles and cracks ...Ca_(12)Al_(14)O_(33)(C12A7)and Y_(0.02)Ca_(11.98)Al_(14)O_(33)(Y-C12A7)single crystals were grown by using the traveling-solvent floating zone(TSFZ)method.The temperature was increased to avoid the bubbles and cracks which may be formed during the preparation of the ingot material.We have started with the flux higher than the normal to avoid the bubbles and make good treatment for the solid-liquid interface.The structures of both Ca_(12)Al_(14)O_(33)(C12A7)and Y_(0.02)Ca_(11.98)Al_(14)O_(33)(Y-C12A7)were studied by using x-ray diffraction(XRD).Optical properties for C12A7 and Y-C12A7 single crystals have been studied in order to determine the optical parameters such as optical energy gap(Eg),refractive index n,oscillating energy(Eo),dispersion energy(Ed),volume energy loss function(VELF),and surface energy loss function(SELF).Finally,a new result for these samples is that the third-order nonlinear optical susceptibility(χ(3))was determined.The results have been discussed with effect of Y-doping on the C12A7 single crystals for optical and industrial applications.展开更多
A novel tolane 4-methoxy-4'-nitro-diphenyl-acetylene (MONA) has been prepared quantitatively by reacting cuprous p-methoxy phenyl-acetylene with p-iodonitrobenzene. A single crystal of the Moan was grown by soluti...A novel tolane 4-methoxy-4'-nitro-diphenyl-acetylene (MONA) has been prepared quantitatively by reacting cuprous p-methoxy phenyl-acetylene with p-iodonitrobenzene. A single crystal of the Moan was grown by solution growth method. The crystal was then characterized by X-ray diffraction structure analysis and second-harmonic generation(SHG)investigation. Polymorphous crystal forms of the MONA were grown from different solvents having different nonlinear optical properties depending on their different crystal structures. The relationship between the crystal growth and crystal structure is discusse.展开更多
Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established base...Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.展开更多
A nonlinear optical single crystal of potassium pentaborate tetrahydrate （KB5O8·4H2O） has been grown from aqueous solution by using unidirectional crystal growth method of Sankaranarayanan-Ramasamy （SR） with ...A nonlinear optical single crystal of potassium pentaborate tetrahydrate （KB5O8·4H2O） has been grown from aqueous solution by using unidirectional crystal growth method of Sankaranarayanan-Ramasamy （SR） with a due modification in the growth assembly. Potassium pentaborate crystal of 60 mm length and 10 mm diameter has been grown along （100） plane with a growth rate of 3 mm per day within a period of 20 days. The grown crystal was subjected to single crystal X-ray diffraction analysis to confirm that the crystal belongs to the orthorhombic system. Some fundamental data such as valance electron plasma energy, Penn gap, Fermi energy and electronic polarizability of the grown crystal were calculated. The presence of borate in the grown crystal was confirmed by Fourier transform infrared （FTIR） spectroscopy. The optical transmission property of the grown crystal was analyzed using ultra violet （UV） visible spectral analysis. Surface morphology of the growth plane was observed using scanning electron microscopy （SEM）. The mechanical strength of the crystals was found out using Vickers microhardness test along the growth axis. Frequency dependent dielectric constant of the grown crystal was studied for various temperatures along （100） plane.展开更多
We propose a novel two-dimensional photonic crystal structure consisting of two line defect waveguides and a cavity to realize mode conversion based on the coupling effect. The W1/cavity/W2 structure breaks the spatia...We propose a novel two-dimensional photonic crystal structure consisting of two line defect waveguides and a cavity to realize mode conversion based on the coupling effect. The W1/cavity/W2 structure breaks the spatial symmetry and successfully converts the even（odd） mode to the odd（even） mode in the W2 waveguide during the forward（backward）transmission. When considering the incidence of only the even mode, the optical diode effect emerges and achieves approximate 35 d B unidirectionality at the resonant frequency. Moreover, owing to the narrow bandpass feature and the flexibility of the tuning cavity, utilization of the proposed structure as a wavelength filter is demonstrated in a device with a Y-branch splitter. Here, we provide a heuristic design for a mode converter, optical diode, and wavelength filter derived from the coupling effect between a cavity and adjacent waveguides, and expect that the proposed structure can be applied as a building block in future all-optical integrated circuits.展开更多
The LiYF4 single crystals singly doped Ho3＋ and co-doped Ho3＋, Pr3＋ ions were grown by a modified Bridgman method. The Judd-Ofelt strength parameters （Ω2, Ω4, Ω6） of No3＋ were calculated according to the abso...The LiYF4 single crystals singly doped Ho3＋ and co-doped Ho3＋, Pr3＋ ions were grown by a modified Bridgman method. The Judd-Ofelt strength parameters （Ω2, Ω4, Ω6） of No3＋ were calculated according to the absorption spectra and the Judd-Ofelt theory, by which the radiative transition probabilities （A）, fluorescence branching ratios （β） and radiative lifetime （τ rad） were obtained. The radiative lifetimes of 5/6 and 5/7 levels in Ho3＋ （1 mol%）：LiYF4 are 10.89 and 20.19 ms, respectively, while 9.77 and 18.50 ms in Ho3＋/pr3＋ doped crystals. Hence, the τ rad of 5/7 level decreases significantly by introduction of Pr3＋ into Ho3＋：LiYF4 crystal which is beneficial to the emission of 2.9 μm. The maximum emission cross section of Ho3＋：LiYF4 crystal located at 2.05 μm calculated by McCumber theory is 0.51 ×10-20 cm2 which is compared with other crystals. The maximum emission cross section at 2948 nm in Ho3＋/pr3＋ co-doped LiYF4 crystal obtained by Fuchtbauer- Ladenburg theory is 0.68 × 10-20 cm2, and is larger than the value of 0.53 × 10-20 cm2 in Ho3＋ singly doped LiYF4 crystal. Based on the absorption and emission cross section spectra, the gain cross section spectra were calculated. In the Ho3- ions singly doped LiYF4 crystal, the gain cross sections for 2.05 μm infrared emission becomes positive once the population inversion level reaches 30%. It means that the pump threshold for obtaining 2.05 μm laser is probably lower which is an advantage for Ho3＋-doped LiYF4 2.05 μm infrared lasers. The calculated gain cross section for 2.9 μm mid-infrared emission does not become positive until the population inversion level reaches 40% in Ho3＋/pr3＋：LiYF4 crystal, but 50% in Ho3＋ singly doped LiYF4 crystal, indicating that a low pumping threshold is achieved for the H03＋：5/6 → 5/7 laser operation with the introduction of Pr3＋ ions. It was also demonstrated that Pr3＋ ion can deplete rapidly the lower laser Ho3＋：5/7 level and has influence on the Ho3＋：5/6 level. The Ho3＋/pr3＋：LiYF4 crystal may be a potential media for 2.9 μm mid-infrared laser.展开更多
The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical ...The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical properties of the resulting fibre to deviate from the designed properties. Therefore, a method of evaluating the optical properties of the actual fibre is necessary for the purpose of application. Up to now, the methods employed to measure the properties of the actual photonic crystal fibre often require long fibre samples or complex expensive equipments. To our knowledge, there are few studies of modeling an actual photonic crystal fibre and evaluating its properties rapidly. In this paper, a novel method, based on the combination model of digital image processing and the finite element method, is proposed to rapidly model the optical properties of the actual photonic crystal fibre. Two kinds of photonic crystal fibres made by Crystal Fiber A/S are modeled. It is confirmed from numerical results that the proposed method is simple, rapid and accurate for evaluating the optical properties of the actual photonic crystal fibre without requiring complex equipment.展开更多
During the process of KDP crystal growth, metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper, KDP crystals were grown from an aqueous solution doped with different ...During the process of KDP crystal growth, metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper, KDP crystals were grown from an aqueous solution doped with different concentration of Fe^3＋ dopant by traditional temperaturereduction method and ＂point-seed＂ rapid growth method. Furthermore, we examined the light scatter and measured the transmission of these KDP crystals. It is found that the dopant of Fe^3＋ ion can improve the stability of the KDP growth solution when its concentration is less than 30 ppm. The effects of Fe^3＋ ion on the growth habit and optical properties of KDP crystal are also obvious.展开更多
The phase diagram, growth and optical property of LaBWO6 crystal are reported. LaBWO6 crystal melts congruently at 1078 ℃. Based on the pseudo-ternary phase diagram of LaBWO6-（Li2WO4/LiF） -B203, the LaBWO6 crystals...The phase diagram, growth and optical property of LaBWO6 crystal are reported. LaBWO6 crystal melts congruently at 1078 ℃. Based on the pseudo-ternary phase diagram of LaBWO6-（Li2WO4/LiF） -B203, the LaBWO6 crystals have been firstly grown by the flux method. LaBWO6 crystal crystallizes in the orthorhombic system, space group P222 with a = 4.1, b = 10.31 and c = 21.71 A. LaBWO6 Crystal exhibits high transparency in a range from 327 to 1100 nm. The absorption edge of the crystal in the UV range is at 293 nm. The SHG efficient of LaBWO6 crystal is 0.3 times as large as that of the KDP crystal.展开更多
Novel isosorbide derivative containing perfluorocarbon group,bi（perfluorooctanesulfonyl）isosorbide ester as chiral dopant in liquid crystal,was synthesized.Chemical structure was characterized by elemental analysis,...Novel isosorbide derivative containing perfluorocarbon group,bi（perfluorooctanesulfonyl）isosorbide ester as chiral dopant in liquid crystal,was synthesized.Chemical structure was characterized by elemental analysis,FT-IR,~1H NMR and ^（19）F NMR.The optical texture of the mixture was observed by polarized optical microscopy（POM）.Novel chiral dopant containing perfluorocarbon group had excellent optical activity.Its specific rotation and molar rotation were noticeable higher than those of bi（4-chloromethylbenzenecarbonic）isosorbide ester.The fluorocarbon group improved the molar rotation of chiral compound and did not affect optical rotation direction.The texture of the mixture added isosorbide derivative with fluorocarbon group showed the oily streak texture.展开更多
The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff oc...The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff occurs at the second quadrant.The second-harmonic-generation efficiency reaches 48%for a 6 mm-long,(113.2°,47.4°)-cut GdCOB,and 41.5%for a 5mm-long,(113°,36.5°)-cut YCOB,respectively.The intracavity frequency doubling of GdCOB is reported for the first time.展开更多
A triphenylamine-containing Schiff base ligand(L), namely, N-(4-(1 H-imidazol-1-yl)benzylidene)-N,N-diphenylbenzene-1,4-diamine, was synthesized and characterized. By coordination of the ligand with CdI2, a complex Cd...A triphenylamine-containing Schiff base ligand(L), namely, N-(4-(1 H-imidazol-1-yl)benzylidene)-N,N-diphenylbenzene-1,4-diamine, was synthesized and characterized. By coordination of the ligand with CdI2, a complex CdI2 L2 was obtained. The structure of the complex was analyzed through single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 25.277(5), b = 11.176(5), c = 17.912(5) ?, β = 106.056(5)°, V = 4863(3) ?3, Z = 4, Dc =1.633 Mg/m3, F(000) = 2360, Μr = 1195.19, μ = 1.766 mm-1, the final R = 0.0323 and wR = 0.0758 for 33414 observed reflections with I > 2?(I). The linear absorption spectra of the complex were experimentally and theoretically studied. And the third-order nonlinear optical(NLO) property of the complex was also measured through Z-scan technique.展开更多
We present a new type of optical filter with an ultra-narrow bandwidth and a wide field-of-view （FOV）. This kind of optical filter consists of one-dimensional photonic crystal （PC） incorporating an anomalous-dispe...We present a new type of optical filter with an ultra-narrow bandwidth and a wide field-of-view （FOV）. This kind of optical filter consists of one-dimensional photonic crystal （PC） incorporating an anomalous-dispersion-material （ADM） with, for instance, an anomalous dispersion of 6P3/2←6S1/2 hyperfine structure transition of a caesium atom. The transmission spectra of optical filters are calculated by using the transfer-matrix method. The simulation results show that the designed optical filter has a bandwidth narrower than 0.33GHz and a wide FOV of ±30°as well. The response of transmission spectrum to an external magnetic field is also investigated.展开更多
zinc cadmium thiocyanate (ZCTC), ZnCd(SCN)_4, has been discoveredas a UV second-order nonlinear optical coordination crystal. Titsthermal and transmission Properties are reported. The thermaldecomposition is character...zinc cadmium thiocyanate (ZCTC), ZnCd(SCN)_4, has been discoveredas a UV second-order nonlinear optical coordination crystal. Titsthermal and transmission Properties are reported. The thermaldecomposition is characterized by using the X-ray Powder diffraction(XRPD) and infrared (IR) spectroscopy at room temperature. TheAbsorptions of intrinsic ions and ZCTC in a solution state arediscussed as well as Transmission properties of the ZCTC crystal. Aneffective method of reducing the surface Reflection loss of ZCTCcrystal is introduced.展开更多
文摘Organic non-linear optical crystal diphenyl urea with molecular formula C13H12N2O was synthesized and grown successfully by slow evaporation solution growth technique. The single crystal X-ray diffraction (XRD) confirms that it crystallizes in orthorhombic crystal system with non-centrosymmetric space group Pna21. The various functional groups were identified qualitatively by Fourier transform-infra red (FT-IR) and FT-Raman techniques. The electron absorption spectrum was studied by UV-Vis spectrophotometer. Thermal behavior of the crystal was evidenced by thermogravimetric (TG) and differential scanning calorimetric (DSC) analyses. From DSC the melt ing point of the crystal is found to be 145°C. The existence of second harmonic generation (SHG) signal was evidenced using Kurtz Perry powder test and the efficiency of the crystal was found to be 0.64 times that of the standard KDP crystal.
基金supports from the National Key Research and Development Program of China(2023YFB2806803)the National Natural Science Foundation of China(62075127).
文摘Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.
基金supported by the National Nat-ural Science Foundation of China(Nos.12192251,12174185,92163216,and 62288101).
文摘The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex beams for various applications.In this work,the second harmonic(SH)optical vortex beams generated from nonlinear fork gratings under Gaussian beam illumination are numerically investigated.The far-field intensity and phase distributions,as well as the orbital angular momentum(OAM)spectra of the SH beams,are analyzed for different structural topological charges and diffraction orders.Results reveal that higher-order diffraction and larger structural topological charges lead to angular interference patterns and non-uniform intensity distributions,deviating from the standard vortex profile.To optimize the SH vortex quality,the effects of the fundamental wave beam waist,crystal thickness,and grating duty cycle are explored.It is shown that increasing the beam waist can effectively suppress diffraction order interference and improve the beam’s quality.This study provides theoretical guidance for enhancing the performance of nonlinear optical devices based on NPCs.
文摘The memory behavior in liquid crystals(LCs)that is characterized by low cost,large area,high speed,and high-density memory has evolved from a mere scientific curiosity to a technology that is being applied in a variety of commodities.In this study,we utilized molybdenum disulfide(MoS_(2))nanoflakes as the vip in a homotropic LCs host to modulate the overall memory effect of the hybrid.It was found that the MoS₂nanoflakes within the LCs host formed agglomerates,which in turn resulted in an accelerated response of the hybrids to the external electric field.However,this process also resulted in a slight decrease in the threshold voltage.Additionally,it was observed that MoS₂nanoflakes in a LCs host tend to align homeotropically under an external electric field,thereby accelerating the refreshment of the memory behavior.The incorporation of a mass fraction of 0.1%2μm MoS₂nanoflakes into the LCs host was found to significantly reduce the refreshing memory behavior in the hybrid to 94.0 s under an external voltage of 5 V.These findings illustrate the efficacy of regulating the rate of memory behavior for a variety of potential applications.
基金supported in part by the National Natural Science Foundation of China(No.52102218)the National Key Research and Development Program of China(No.2020YFA0710303)+2 种基金the Fujian Science&Technology Innovation Laboratory for Op-toelectronic Information of China(No.2021ZZ127)the Minjiang Scholar Professorship(No.GXRC-21004)the Natural Science Foundation of Fujian Province of China(No.2021J01594)。
文摘Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)through the high-temperature solid-state spontaneous crystallization method.Different from the cubicα-Pb_(3)P_(2)S_(8),theβ-Pb_(3)P_(2)S_(8)crystallizes in the orthorhombic Pbcn space group.Notably,β-Pb_(3)P_(2)S_(8)shows a large band gap of 2.37 e V in lead-based chalcogenides,wide infrared transparent window(2.5-15μm),and excellent thermal stability.Importantly,the experimental birefringence shows the largest value of0.26@550 nm in chalcogenides,even larger than the commercialized oxide materials.The Barder charge analysis result indicates that the exceptional birefringence effect is mainly from the Pb^(2+)and S^(2-)in the[Pb S_n]polyhedrons.Meanwhile,the parallelly arranged polyhedral layers could improve the structural anisotropic.Therefore,this work supports a new method for designing chalcogenides with exceptional birefringence effect in the infrared region.
文摘Ca_(12)Al_(14)O_(33)(C12A7)and Y_(0.02)Ca_(11.98)Al_(14)O_(33)(Y-C12A7)single crystals were grown by using the traveling-solvent floating zone(TSFZ)method.The temperature was increased to avoid the bubbles and cracks which may be formed during the preparation of the ingot material.We have started with the flux higher than the normal to avoid the bubbles and make good treatment for the solid-liquid interface.The structures of both Ca_(12)Al_(14)O_(33)(C12A7)and Y_(0.02)Ca_(11.98)Al_(14)O_(33)(Y-C12A7)were studied by using x-ray diffraction(XRD).Optical properties for C12A7 and Y-C12A7 single crystals have been studied in order to determine the optical parameters such as optical energy gap(Eg),refractive index n,oscillating energy(Eo),dispersion energy(Ed),volume energy loss function(VELF),and surface energy loss function(SELF).Finally,a new result for these samples is that the third-order nonlinear optical susceptibility(χ(3))was determined.The results have been discussed with effect of Y-doping on the C12A7 single crystals for optical and industrial applications.
文摘A novel tolane 4-methoxy-4'-nitro-diphenyl-acetylene (MONA) has been prepared quantitatively by reacting cuprous p-methoxy phenyl-acetylene with p-iodonitrobenzene. A single crystal of the Moan was grown by solution growth method. The crystal was then characterized by X-ray diffraction structure analysis and second-harmonic generation(SHG)investigation. Polymorphous crystal forms of the MONA were grown from different solvents having different nonlinear optical properties depending on their different crystal structures. The relationship between the crystal growth and crystal structure is discusse.
基金financial support from National Natural Science Foundation of China(No.61775120).
文摘Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.
文摘A nonlinear optical single crystal of potassium pentaborate tetrahydrate （KB5O8·4H2O） has been grown from aqueous solution by using unidirectional crystal growth method of Sankaranarayanan-Ramasamy （SR） with a due modification in the growth assembly. Potassium pentaborate crystal of 60 mm length and 10 mm diameter has been grown along （100） plane with a growth rate of 3 mm per day within a period of 20 days. The grown crystal was subjected to single crystal X-ray diffraction analysis to confirm that the crystal belongs to the orthorhombic system. Some fundamental data such as valance electron plasma energy, Penn gap, Fermi energy and electronic polarizability of the grown crystal were calculated. The presence of borate in the grown crystal was confirmed by Fourier transform infrared （FTIR） spectroscopy. The optical transmission property of the grown crystal was analyzed using ultra violet （UV） visible spectral analysis. Surface morphology of the growth plane was observed using scanning electron microscopy （SEM）. The mechanical strength of the crystals was found out using Vickers microhardness test along the growth axis. Frequency dependent dielectric constant of the grown crystal was studied for various temperatures along （100） plane.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61372037 and 61307069)Beijing Excellent Ph.D. Thesis Guidance Foundation,China(Grant No.20131001301)the Natural Science Foundation of Shanxi Province,China(Grant No.2013021017-3)
文摘We propose a novel two-dimensional photonic crystal structure consisting of two line defect waveguides and a cavity to realize mode conversion based on the coupling effect. The W1/cavity/W2 structure breaks the spatial symmetry and successfully converts the even（odd） mode to the odd（even） mode in the W2 waveguide during the forward（backward）transmission. When considering the incidence of only the even mode, the optical diode effect emerges and achieves approximate 35 d B unidirectionality at the resonant frequency. Moreover, owing to the narrow bandpass feature and the flexibility of the tuning cavity, utilization of the proposed structure as a wavelength filter is demonstrated in a device with a Y-branch splitter. Here, we provide a heuristic design for a mode converter, optical diode, and wavelength filter derived from the coupling effect between a cavity and adjacent waveguides, and expect that the proposed structure can be applied as a building block in future all-optical integrated circuits.
基金supported by the National Natural Science Foundation of China(Grant Nos.51272109 and 50972061)the Natural Science Foundation of Zhejiang Province(Grant Nos.R4100364)the Natural Science Foundation of Ningbo City(Grant No.2012A610115)
文摘The LiYF4 single crystals singly doped Ho3＋ and co-doped Ho3＋, Pr3＋ ions were grown by a modified Bridgman method. The Judd-Ofelt strength parameters （Ω2, Ω4, Ω6） of No3＋ were calculated according to the absorption spectra and the Judd-Ofelt theory, by which the radiative transition probabilities （A）, fluorescence branching ratios （β） and radiative lifetime （τ rad） were obtained. The radiative lifetimes of 5/6 and 5/7 levels in Ho3＋ （1 mol%）：LiYF4 are 10.89 and 20.19 ms, respectively, while 9.77 and 18.50 ms in Ho3＋/pr3＋ doped crystals. Hence, the τ rad of 5/7 level decreases significantly by introduction of Pr3＋ into Ho3＋：LiYF4 crystal which is beneficial to the emission of 2.9 μm. The maximum emission cross section of Ho3＋：LiYF4 crystal located at 2.05 μm calculated by McCumber theory is 0.51 ×10-20 cm2 which is compared with other crystals. The maximum emission cross section at 2948 nm in Ho3＋/pr3＋ co-doped LiYF4 crystal obtained by Fuchtbauer- Ladenburg theory is 0.68 × 10-20 cm2, and is larger than the value of 0.53 × 10-20 cm2 in Ho3＋ singly doped LiYF4 crystal. Based on the absorption and emission cross section spectra, the gain cross section spectra were calculated. In the Ho3- ions singly doped LiYF4 crystal, the gain cross sections for 2.05 μm infrared emission becomes positive once the population inversion level reaches 30%. It means that the pump threshold for obtaining 2.05 μm laser is probably lower which is an advantage for Ho3＋-doped LiYF4 2.05 μm infrared lasers. The calculated gain cross section for 2.9 μm mid-infrared emission does not become positive until the population inversion level reaches 40% in Ho3＋/pr3＋：LiYF4 crystal, but 50% in Ho3＋ singly doped LiYF4 crystal, indicating that a low pumping threshold is achieved for the H03＋：5/6 → 5/7 laser operation with the introduction of Pr3＋ ions. It was also demonstrated that Pr3＋ ion can deplete rapidly the lower laser Ho3＋：5/7 level and has influence on the Ho3＋：5/6 level. The Ho3＋/pr3＋：LiYF4 crystal may be a potential media for 2.9 μm mid-infrared laser.
基金Project supported by the National Basic Research Program of China(Grant No.2010CB328206)the National Natural Science Foundation of China(Grant No.60977033)the Science and Technology Innovation Foundation for Excellent Doctors of Beijing Jiaotong University,China(Grant Nos.141055522 and 141060522)
文摘The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical properties of the resulting fibre to deviate from the designed properties. Therefore, a method of evaluating the optical properties of the actual fibre is necessary for the purpose of application. Up to now, the methods employed to measure the properties of the actual photonic crystal fibre often require long fibre samples or complex expensive equipments. To our knowledge, there are few studies of modeling an actual photonic crystal fibre and evaluating its properties rapidly. In this paper, a novel method, based on the combination model of digital image processing and the finite element method, is proposed to rapidly model the optical properties of the actual photonic crystal fibre. Two kinds of photonic crystal fibres made by Crystal Fiber A/S are modeled. It is confirmed from numerical results that the proposed method is simple, rapid and accurate for evaluating the optical properties of the actual photonic crystal fibre without requiring complex equipment.
基金the State High Technology Program for Inertial Confinement Fusion and National Science Foundation (No.59823003)Project of United Foundation (No.10676019)Youth Scientist Fund of Shandong Province (Nos. 2004BS04022 and 03BS079)
文摘During the process of KDP crystal growth, metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper, KDP crystals were grown from an aqueous solution doped with different concentration of Fe^3＋ dopant by traditional temperaturereduction method and ＂point-seed＂ rapid growth method. Furthermore, we examined the light scatter and measured the transmission of these KDP crystals. It is found that the dopant of Fe^3＋ ion can improve the stability of the KDP growth solution when its concentration is less than 30 ppm. The effects of Fe^3＋ ion on the growth habit and optical properties of KDP crystal are also obvious.
基金Supported by the NNSFC (No.61275177)the NSF of Fujian Province (No.2012I0011)
文摘The phase diagram, growth and optical property of LaBWO6 crystal are reported. LaBWO6 crystal melts congruently at 1078 ℃. Based on the pseudo-ternary phase diagram of LaBWO6-（Li2WO4/LiF） -B203, the LaBWO6 crystals have been firstly grown by the flux method. LaBWO6 crystal crystallizes in the orthorhombic system, space group P222 with a = 4.1, b = 10.31 and c = 21.71 A. LaBWO6 Crystal exhibits high transparency in a range from 327 to 1100 nm. The absorption edge of the crystal in the UV range is at 293 nm. The SHG efficient of LaBWO6 crystal is 0.3 times as large as that of the KDP crystal.
基金the financial support from the National Natural Science Foundation of China(No.20776030)
文摘Novel isosorbide derivative containing perfluorocarbon group,bi（perfluorooctanesulfonyl）isosorbide ester as chiral dopant in liquid crystal,was synthesized.Chemical structure was characterized by elemental analysis,FT-IR,~1H NMR and ^（19）F NMR.The optical texture of the mixture was observed by polarized optical microscopy（POM）.Novel chiral dopant containing perfluorocarbon group had excellent optical activity.Its specific rotation and molar rotation were noticeable higher than those of bi（4-chloromethylbenzenecarbonic）isosorbide ester.The fluorocarbon group improved the molar rotation of chiral compound and did not affect optical rotation direction.The texture of the mixture added isosorbide derivative with fluorocarbon group showed the oily streak texture.
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No.69890235the Key Program of Science and Technology Research of the Minis try of Education of China under Grant No.99182.
文摘The nonlinear-optical coefficients of RCOB(R=Gd,Y)crystals are measured.The spatial distribution of deff effective nonlinear-optical coefficient is determined subsequently.Our experiments show that the maximum deff occurs at the second quadrant.The second-harmonic-generation efficiency reaches 48%for a 6 mm-long,(113.2°,47.4°)-cut GdCOB,and 41.5%for a 5mm-long,(113°,36.5°)-cut YCOB,respectively.The intracavity frequency doubling of GdCOB is reported for the first time.
基金supported by the Major Project of Natural Science Research in Universities of Anhui Province(KJ2018ZD037,KJ2018A0333)Key Project of Youth Talents in Universities of Anhui Province(gxyqZD2017067)+4 种基金National Natural Science Foundation of China(21401024)Natural Science Foundation of Anhui Province(1508085MB21)National Students Research Training Program(201710371099,201710371019)Research Innovation Team of Fuyang Normal University(kytd201710)Horizontal Cooperation Project of Fuyang Municipal Government and Fuyang Normal University(XDHX2016011,XDHX2016004)
文摘A triphenylamine-containing Schiff base ligand(L), namely, N-(4-(1 H-imidazol-1-yl)benzylidene)-N,N-diphenylbenzene-1,4-diamine, was synthesized and characterized. By coordination of the ligand with CdI2, a complex CdI2 L2 was obtained. The structure of the complex was analyzed through single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 25.277(5), b = 11.176(5), c = 17.912(5) ?, β = 106.056(5)°, V = 4863(3) ?3, Z = 4, Dc =1.633 Mg/m3, F(000) = 2360, Μr = 1195.19, μ = 1.766 mm-1, the final R = 0.0323 and wR = 0.0758 for 33414 observed reflections with I > 2?(I). The linear absorption spectra of the complex were experimentally and theoretically studied. And the third-order nonlinear optical(NLO) property of the complex was also measured through Z-scan technique.
基金Project supported by the National Basic Research Program of China （Grant No 001CB61040） and the Natural Science Foundation of Beijing, China （Grant No1032003）.
文摘We present a new type of optical filter with an ultra-narrow bandwidth and a wide field-of-view （FOV）. This kind of optical filter consists of one-dimensional photonic crystal （PC） incorporating an anomalous-dispersion-material （ADM） with, for instance, an anomalous dispersion of 6P3/2←6S1/2 hyperfine structure transition of a caesium atom. The transmission spectra of optical filters are calculated by using the transfer-matrix method. The simulation results show that the designed optical filter has a bandwidth narrower than 0.33GHz and a wide FOV of ±30°as well. The response of transmission spectrum to an external magnetic field is also investigated.
文摘zinc cadmium thiocyanate (ZCTC), ZnCd(SCN)_4, has been discoveredas a UV second-order nonlinear optical coordination crystal. Titsthermal and transmission Properties are reported. The thermaldecomposition is characterized by using the X-ray Powder diffraction(XRPD) and infrared (IR) spectroscopy at room temperature. TheAbsorptions of intrinsic ions and ZCTC in a solution state arediscussed as well as Transmission properties of the ZCTC crystal. Aneffective method of reducing the surface Reflection loss of ZCTCcrystal is introduced.
