Studies on two-photon pumped frequency up-converted lasing properties of a new material HMASPS

Abstract

A new dye trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulphonate (abbreviated as HMASPS) was synthesized, the two-photon absorption (TPA), TPA-induced frequency up-conversion emission, and two-photon pumped (TPP) frequency up-converted lasing properties of HMASPS were experimentally studied. This new dye has a moderate TPA cross-section of σ₂ = 6.0 × 10^?48 cm⁴ s photon^?1, but exhibits a high lasing efficiency. The net conversion efficiency from the absorbed 1064 nm pump pulse energy to the 630 nm up-converted lasing energy is 4% at a pump energy level of 4mJ.     

Superradiance and lasing properties of new two-photon absorption dye DEASPS

Pumped by picosecond pulses from a Nd:YAG laser, a new lasing dye, trans-4-[4′-(N,N-diethylamino)styryl]-N-methyl pyridinium methyl sulfate (abbreviated to DEASPS), shows both intense superradiance and strong lasing properties in benzyl alcohol solution. By using streak camera systems, the superradiance and lasing can be distinguished both spectrally and temporally. It has been found that the peak wavelength of lasing is at 620 nm with a red-shift of about 12 nm to the superradiance wavelength. The lasing pulse shows an oscillatory effect that it is not found in the superradiance pulse. The fluorescence lifetime is 529 ± 40 ps and the effective molecular two-photon absorption is (1.25 ± 0.1) × 10^?48 cm⁴ ·s·photon ^?1, measured using a nonlinear transmittance method. This dye shows effective optical limiting of the pumping wavelength.     

Upconversion fluorescence and optical power limiting effects based on the two- and three-photon absorption process of a new organic dye BPAS

A new organic dye, trans-4, 4'-bis(pyrrolidingl) stilbene (BPAS), with large two-photon absorption (TPA) and three-photon absorption (3PA) has been synthesized. The molecular TPA cross section sigma2' at 550-670 nm and the 3PA cross section sigma3' at 720-1000 nm have been measured. The biggest sigma2' and sigma3' was 5.77 x 10(-47) cm4s/photon and 27 x 10(-75) cm6 s2 at 600 and 980 nm, respectively. In the experiment process we found that the strongest TPA wavelength is not at two times of the strongest linear absorption wavelength, but there is some blue shift. The 3PA-induced optical power-limiting properties have also been illustrated at 980 nm.     

新型荧光材料的合成与表征

以二水合-[N,N,-双(2-苯胺基)乙二酰胺]合镍和邻菲咯啉(phen)为原料合成了一种新型荧光材料,并用元素分析、红外、紫外、核磁共振等进行了表征,通过对其荧光性能的研究,证明该化合物是一种较好的新型荧光材料.     

一种有机染料的双光子荧光性质及反应中间体的晶体结构

合成了一种新的有机染料1,2,4,5-四(4-吡啶乙烯基)苯1,2,4,5-tetrakis(4-pyridylvinyl)benzene(简称为TVPB)并测试了其双光子荧光性质.溶剂缓慢挥发法得到了其反应中间体1,2,4,5-四(二甲氧基膦酰甲基)苯1,2,4,5-tetra (dimethoxyphosphorylmethyl)benzene(简称为TDMPMB)的晶体.用X射线四圆衍射仪对晶体结构进行了解析.     

Two-photon pumped upconversion and nonlinear optical properties of a new lasing dye: HMASPS

Abstract

Two-photon pumped frequency upconversion optical properties and two-photon absorption (TPA) induced nonlinear absorption of a new dye, trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium ptoluene sulfonate (abbreviated to HMASPS) have been experimentally investigated. This new dye exhibits strong superradiation properties when the pumping power is above its threshold. The superradiation upconversion efficiency from 900 to 1150 nm and the nonlinear absorption from 720 to 1100 nm have been measured. The largest effective molecular TPA cross-section was measured to be 44.3 × 10^?48 cm⁴·s·photon^?1at 920 nm. At 1064 nm, it was 2.77 × 10^?48 cm⁴·s·photon^?1, much smaller than that at 920 nm. The highest conversion efficiency is 7% at 990 nm, whereas 4.2% at 1064 nm.     

Spectroscopy and laser characteristics of copper-vapor-laser pumped pyrromethene-556 and pyrromethene-567 dye solutions

We measured the basic optical properties of Pyrromethene-567 (P567) and Pyrromethene-556 (P556) dye solutions that are relevant to their application as dye lasers. The fluorescence spectra of methanol solutions show mirror images in relation to the absorption spectra, with Stokes shifts of 29.5 and 37.5 nm, respectively, for the two dyes. The central fluorescence peaks were at 546 and 535 nm, with widths of ~40 and ~50 nm (FWHM). The quantum yields were 97% ? 5% and 78% ? 5% for P567 and P556, respectively. Fluorescence lifetimes of 6.0 ? 0.2 ns were obtained for both dyes in methanol. Laser action, obtained by pumping with the green emission line (510.6 nm) from a copper-vapor laser, was measured in a H?nsch-type cavity. Tunability ranged from 531 to 590 nm for P567 and from 522 to 590 nm for P556. Lasing thresholds were ~0.27 and ~0.16 mJ/pulse, with 25% and 27% slope efficiencies for P567 and P556, respectively. Spectroscopy and lasing were studied in other solvents as well.     

新型树状芳-脂共聚酰胺的合成及其荧光性能研究

用溶液缩聚法合成一系列新型的树状芳香-脂肪共聚酰胺.通过红外、核磁等表征了其结构,并对其荧光性能进行了研究.     

一类新型的超支化芳香-脂肪共聚酰胺的合成及其荧光性能研究

用溶液缩聚法合成一系列新型的超支化芳香-脂肪共聚酰胺。通过红外和核磁等表征了其结构．并对其荧光性能进行了研究。     

Studies on the adsorption of reactive brilliant red X-3B dye on organic and carbon aerogels

Organic aerogels (AGs) and carbon aerogels (CAs) as adsorbents were successfully fabricated by a sol-gel polymerization method. The BET specific surface area and pore size distribution of the samples were analyzed by N(2) adsorption measurements. The adsorption efficiency of prepared samples towards reactive brilliant red X-3B dye (RBRX) was investigated. The adsorption of dye was found to follow the Langmuir and Freundlich models. The thermodynamic parameters, such as the change of free energy, enthalpy and entropy were calculated from equilibrium constants. Kinetic studies indicated that the adsorption of CA followed pseudo first and second order kinetic model, but the adsorption of AG only followed pseudo first order kinetic model. Batch adsorption studies were conducted to evaluate the effects of main preparation and adsorption conditions such as R/C (molar ratio of resorcinol (R) to surfactant (CTAB)) of adsorbent, pH, adsorbent dose and adsorbent particle size on the adsorption of RBRX on AG and CA. The results showed that the adsorption capacity of dye increased with the decrease in dose and particle size of the adsorbent. Maximum adsorption of AGs and CAs was observed at R/C=200. The adsorption capacity of AG and CA would increase largely when pH<4 or pH>12.     

新型GSH荧光传感材料的合成与性能研究

以罗丹明B酰肼为荧光发光团,设计并合成了一种带有二硫键的荧光探针RNSS,该探针在乙腈与水溶液（v/v=1∶1）中可以特异性地识别谷胱甘肽（GSH）。通过红外光谱、核磁共振谱图、荧光光谱对探针的结构与性能进行表征与分析。实验结果表明,当向探针溶液中加入GSH后,在561 nm光的激发下,其在585 nm处出现明显的粉色荧光,并且其他氨基酸没有荧光响应,表明其具有良好的专一选择性以及抗干扰能力;同时探针对GSH的检出限为6.063×10^-6 mol/L,说明其具有高灵敏性;经荧光光谱滴定曲线与Job-plot分析可知二者通过二硫键取代反应以1∶1的方式形成配合物。     

有机材料DCJTB在分层点粉中对白光LED发光特性的影响

通过在LED芯片上涂敷有机材料DCJTB,然后点YAG荧光粉的方法来研究白光LED分层点粉的激发光谱,其中DCJTB的混合质量分数分别为0、1%、2%、3%、5%、10%。结果表明,随着DCJTB混合浓度的增加,550～750nm波段的黄光、红光区域峰值明显增加且在600nm附近达到最大值,光谱色坐标从白光区域（0.2856、0.2883）向红光区域（0.4373、0.3377）移动,其LED的显色指数达到峰值88.2。因此采用分层点粉的方式可以使LED芯片发出的能量激发有机材料DCJTB,使得到的红光与芯片剩余能量激发YAG荧光粉的黄光组合得到显色指数较好的白光。     

Influence of optical properties on two-photon fluorescence imaging in turbid samples

A numerical model was developed to simulate the effects of tissue optical properties, objective numerical aperture (N.A.), and instrument performance on two-photon-excited fluorescence imaging of turbid samples. Model data are compared with measurements of fluorescent microspheres in a tissuelike scattering phantom. Our results show that the measured two-photon-excited signal decays exponentially with increasing focal depth. The overall decay constant is a function of absorption and scattering parameters at both excitation and emission wavelengths. The generation of two-photon fluorescence is shown to be independent of the scattering anisotropy, g, except for g > 0.95. The N.A. for which the maximum signal is collected varies with depth, although this effect is not seen until the focal plane is greater than two scattering mean free paths into the sample. Overall, measurements and model results indicate that resolution in two-photon microscopy is dependent solely on the ability to deliver sufficient ballistic photon density to the focal volume. As a result we show that lateral resolution in two-photon microscopy is largely unaffected by tissue optical properties in the range typically encountered in soft tissues, although the maximum imaging depth is strongly dependent on absorption and scattering coefficients, scattering anisotropy, and objective N.A..     

New designs and simulations of a 10-kW average-power longitudinally pumped dye laser amplifier

New designs of a 10-kW average-power longitudinally pumped dye laser amplifier pumped by a copper laser and its operating simulations are presented. The new designs, which use a center-hole mirror, make it possible to pump longitudinally without dichroic mirrors. The simulations take into consideration the time-dependent excited-state absorption of both the laser and the pump beam. Dye laser amplifiers, with an input dye laser average power of 10 kW, are simulated. The simulation results suggest that a better than 50% extraction efficiency can be obtained with two pump beams of more than 1 kW. The results also suggest that an amplified gain of 10 with an extraction efficiency of approximately 50% can be obtained with the double-pass amplifier.     

有机薄膜的场效应非线性电阻特性

本文报道一种新型的、准球形的有机分子材料TPR-1(四(吡咯-1-基-甲基)甲烷).这种有机分子含有四个吡咯基团,容易通过真空热蒸发成膜.在紫外光作用下,还可以原位交联,形成较稳定的半导体薄膜.实验中,分别用Cu或Al作为顶底电极,制作夹层器件,发现样品导电能力随外加电压变化存在明显的非线性变化特征,开关斜率比最高可达50倍,频率相应范围在50Hz～10kHz,并具有良好的重复性和稳定性.     

Electrophoretically mediated microanalysis of leucine aminopeptidase using two-photon excited fluorescence detection on a microchip

Two-photon excited fluorescence detection was performed on a microfabricated electrophoresis chip. A calibration curve of the fluorescent tag beta-naphthylamine was performed, resulting in a sensitivity of 2.5 x 10(9) counts M(-1) corresponding to a detection limit of 60 nM. Additionally, leucine aminopeptidase was assayed on the chip using electrophoretically mediated microanalysis. The differential electroosmotic mobilities of the enzyme and substrate, L-leucine beta-naphthylamide, allowed for efficient mixing in an open channel, resulting in the detection of a 30 nM enzyme solution under constant potential. A zero potential incubation for 1 min yielded a calculated detection limit of 4 nM enzyme.     

Spent tea leaves: a new non-conventional and low-cost adsorbent for removal of basic dye from aqueous solutions

In the present study, spent tea leaves (STL) were used as a new non-conventional and low-cost adsorbent for the cationic dye (methylene blue) adsorption in a batch process at 30 degrees C. Equilibrium sorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption isotherm data were fitted well to the Langmuir isotherm and the monolayer adsorption capacity was found to be 300.052mg/g at 30 degrees C. The kinetic data obtained at different initial concentrations were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The results revealed that the spent tea leaves, being waste, have the potential to be used as a low-cost adsorbent for the removal of methylene blue from aqueous solutions.     

Probing solvent fractionation in electrospray droplets with laser-induced fluorescence of a solvatochromic dye

Laser-induced fluorescence spectroscopy is used to profile solvent fractionation in an electrospray plume containing Nile Red, a solvatochromic dye (i.e., a dye for which spectral features are sensitive to solvent polarity). The results confirm gradual enrichment of the less volatile component in spray droplets as a result of solvent evaporation. Changes in solvent composition are evident in both axial and lateral profiles. The influences of capillary voltage, nebulizing gas, an electrolyte modifier, and flow rate on the extent of solvent fractionation are assessed. The results suggest that, in addition to volatility of the solvents, major factors affecting solvent fractionation include initial droplet size, droplet velocity, and the cooling effect of the nebulizing gas. Isolating contributions from these factors will require complementary data from other experiments.