Polymers are a kind of attractive hosts for laser dyes due to their high transparency in both pumping and lasing ranges and superior optical homogeneity. In this paper solid dye samples based on polymethyl methacryla...Polymers are a kind of attractive hosts for laser dyes due to their high transparency in both pumping and lasing ranges and superior optical homogeneity. In this paper solid dye samples based on polymethyl methacrylate （PMMA） doped with different concentrations of 1, 3, 5, 7, 8 -pentamethyl-2, 6-diethylpyrromethene-BF2 （PM567） are prepared. The absorption, fluorescence and lasing spectra of the samples are obtained. Wide absorption and fluorescence bands are obtained and a red shift of the maxima of the lasing emission spectra is observed. With the second-harmonic generation of Q-switched Nd：YAC laser （532 nm, -20 ns） pumping the samples longitudinally, the slope efficiencies of the samples are obtained. There is an optimal dye concentration for the highest slope efficiency when the pumping energy is lower than some typical value （-250 mJ）, and the highest slope efficiency 35.6% is obtained in the sample with a dye concentration of 2 × 10^-4 mol/L. Pumping the samples at a rate of 10Hz with a pulse energy as high as 200 mJ （the fluence is 0.2 J/cm^2）, the output energy drops to one-half of its initial value after approximate 15500 pulses and the normalized photostability is 5.17CJ/mol. A kind of solid dye laser which could have some applications is built.展开更多
Laser action in methyl methacrylate （MMA） co-doped with sulforhodamine B and crystal violet dyes was investi- gated. The dye mixture was incorporated into a solid polymeric matrix and was pumped by a 532-nm Nd：YAG ...Laser action in methyl methacrylate （MMA） co-doped with sulforhodamine B and crystal violet dyes was investi- gated. The dye mixture was incorporated into a solid polymeric matrix and was pumped by a 532-nm Nd：YAG laser. Distributed feedback dye laser （DFDL） action was induced in the dye mixture using a prism arrangement both in the donor and acceptor regions by an energy transfer mechanism. Theoretically, the characteristics of acceptor and donor DFDLs, and the dependence of their pulse widths and output powers on acceptor-donor concentrations and pump power, were studied. Experimentally, the output energy of DFDL was measured at the emission peaks of donor and acceptor dyes for different pump powers and different acceptor-donor concentrations. Tuning of the output wavelength was achieved by varying the period of the gain modulation of the laser medium. The laser wavelength showed continuous tunability from 563 nm to 648 nm.展开更多
In order to obtain a high output energy from a xenon lamp-pumped solid-state dye laser, homogeneities of laser mediums and flatnesses of medium faces with different processing treatments are discussed in the paper. Th...In order to obtain a high output energy from a xenon lamp-pumped solid-state dye laser, homogeneities of laser mediums and flatnesses of medium faces with different processing treatments are discussed in the paper. The mediums without aging treatment, which are prepared by using a prepolymer process and have diamond-machined end faces to produce the required optical finish, give a highest laser output of 281.9 mJ with 0.215% slope efficiency at 2.0x 10^-4 mol/L. The best medium lifetime is 21 shots to 50% of original output equating 74.6 k J/liter.展开更多
A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl- pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulse...A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl- pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HEASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 9.1% which is higher than that of known TPP laser dyes trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI) and trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) at the same experimental conditions.展开更多
The solid-state medium containing pyrromethene 567 （PM567） in a polymethylmethacrylate polymer host is shown to lase under the flash lamp excitation. The experimental setup is an ordinary industrial product without ...The solid-state medium containing pyrromethene 567 （PM567） in a polymethylmethacrylate polymer host is shown to lase under the flash lamp excitation. The experimental setup is an ordinary industrial product without special design. The bulk transmission losses, the output energy, and the other lasing properties are compared. The medium with the lowest transmission loss, measured to be 0.392 %/cm at 633 nm, gives a laser output of 130 mJ with a slope efficiency of 0.082%.展开更多
Solid-state tunable dye laser materials developed by incorporation of stable laser dye molecules into solid host matrices like polymers, organically modified silicates (ORMOSILS) and porous sol-gel glasses. These mate...Solid-state tunable dye laser materials developed by incorporation of stable laser dye molecules into solid host matrices like polymers, organically modified silicates (ORMOSILS) and porous sol-gel glasses. These materials have technical advantages such as compactness, better manageability and suitability for field measurement. The recent research work with highly porous sol-gel glasses having good transparency in UV-Near UV region used as solid host for solid-state dye laser materials has attracted a great deal of attention because of its high potential utility than polymers. Two different procedure’s are used for incorpoerating the Stilbine-3 (STB-3) laser dyes into porous sol-gel matrices such as dope or dip methods. In dope method dye is mixed at the sol state and drying is carried out afterward;while in dip method matrix is first prepared and the matrix is dipped in desired dye solution. After preparation of these dye embedded sol-gel glasses we studied their spectroscopic properties of using absorption and fluorescence spectroscopy. Along with spectroscopy properties, the studies for longevity or the shelf life and lasing action of these materials were carried out. Laser dye STB-3 incorporated in sol-gel glass samples shows the same result as in methanolic solution.展开更多
To assess the effectiveness of the flashlamp- pumped pulsed dye laser (Photogeneca V, Synosure Corp, Boston, United States) in the treatment of port- wine stains. Methods. One hundred and ninety- four consecutive pati...To assess the effectiveness of the flashlamp- pumped pulsed dye laser (Photogeneca V, Synosure Corp, Boston, United States) in the treatment of port- wine stains. Methods. One hundred and ninety- four consecutive patients with port- wine stains were treated with a flashlamp- pumped pulsed dye laser in Peking Union Medical College Hospital from January 1998 to August 1999. Results. Of 194 patients who completed treatment, 56.2％ had more than 60％ fading of the lesion and only 6.7％ had less than 20％ fading. An average of 3.6 treatments were needed to achieve more than 60％ fading. The response was better in children than in adults, although the difference was not significant. Pigmentary change (usually transient) occurred in 3.1％ of patients. Conclusions. This study confirms the efficacy of the flashlamp- pumped pulsed dye laser in the treatment of port- wine stains in children and adults.展开更多
A new organic dye, trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser p...A new organic dye, trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HMASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 8.4% which is higher than that of trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI)(1) at the same pump level.展开更多
Under high-excitation irradiance conditions to induce fluorescence, the dependence of photobleaching of Coumarin 307 （C307） and acriflavine （ACF） laser dyes in liquid and solid phases have been studied. A cw LD la...Under high-excitation irradiance conditions to induce fluorescence, the dependence of photobleaching of Coumarin 307 （C307） and acriflavine （ACF） laser dyes in liquid and solid phases have been studied. A cw LD laser source of 1 mW and 407 nm wavelength was used as an exciting source. For one hour exposure time, it was found that the solid dye samples suffer photobleaching more than the liquid dye samples. This is because in liquid solutions the dye molecules can circulate during the irradiation, while the photobleaching is a serious problem when the dye is incorporated into solid matrix and cannot circulate.展开更多
In 1967 the first work in solid state dye laser was performed by doping rhodamine dyes in Polymethylmethacrylate (PMMA) materials. Since then </span><span style="white-space:normal;"><spa...In 1967 the first work in solid state dye laser was performed by doping rhodamine dyes in Polymethylmethacrylate (PMMA) materials. Since then </span><span style="white-space:normal;"><span style="font-family:"">some</span></span><span style="white-space:normal;"><span style="font-family:""> materials like various types of polymers, co-polymers, poly</span></span><span style="white-space:normal;"><span style="font-family:""> </span></span><span style="white-space:normal;"><span style="font-family:"">composite glasses have been used as host matrices for doping different laser dyes. Polymers suffer from limited mechanical and thermal stability. Hence glasses can be the alternative hosts. However, because of high processing temperature leading to permanent destruction of dye molecules, </span></span><span style="white-space:normal;"><span style="font-family:"">the </span></span><span style="white-space:normal;"><span style="font-family:"">conventional glass preparation technique is not suitable for the introduction of organic laser dyes. This difficulty can be overcome by introducing the laser dye molecules in sol-gel glass which is prepared at low temperature. Recent work with sol-gel glasses shows that these glasses may prove to be better materials compared to polymeric materials because glasses being hard, best optically transparency in Near UV-UV and Visible region and show better photostability. In this research work we reported, comparative study of the photophysical properties of Coumarin-120 (C-120) belonging to 7-aminocoumarin family having two hydrogen atoms attached to the N atom at the 7-position, with Stilbene-3 (STB-3) in three types of HCl catalyzed SiO<sub>2</sub> sol-gel matrices prepared by Method I, Method II and Method III respectively.展开更多
AIM:To document the prognosis of laser treatment in patients with exudative age-related macular degeneration(AMD).· METHODS:Efficacy of the intervention was evaluated using a before-after method.· RESULTS:A ...AIM:To document the prognosis of laser treatment in patients with exudative age-related macular degeneration(AMD).· METHODS:Efficacy of the intervention was evaluated using a before-after method.· RESULTS:A total of 392 eyes of 341 patients with exudative AMD were examined.77.6% had choroideal neovascularisation(CNV).Before the use of indocyanine green(ICG) angiography,occult CNV was detected in only 1.8% of the eyes,but after the use of ICG angiography,this increased to 19.5%(P<0.001).Of the 349 eyes which were followed up,visual acuity had remained stable in 68.2% of the eyes.There was a statistically significant relationship between localisation of lesion and visual acuity changes on pre-and post-laser treatment(P<0.001).Also there was a statistically significant relationship between localisation of lesion and recurrence(P<0.05).The recurrence was less in subfoveal lesions than that in juxtafoveal and extrafoveal lesions.· CONCLUSION:ICG angiography is highly important in the treatment of occult CNV.展开更多
Background:Hypertrophic scars and keloids,common complications following median sternotomy for cardiac surgery,significantly impact patient quality of life due to their aesthetic and symptomatic burden.Recent advanceme...Background:Hypertrophic scars and keloids,common complications following median sternotomy for cardiac surgery,significantly impact patient quality of life due to their aesthetic and symptomatic burden.Recent advancements in laser therapy have made it a prominent option for managing these complex scars,yet a com-prehensive understanding of its efficacy is lacking.The aim of this scoping review is to explore the effects of laser therapy in managing hypertrophic scars and keloids after median sternotomy.Methods:This scoping review ana-lyzed studies up to February 2024 from databases including PubMed,EMBASE,CINAHL,Scopus,Web of Science,and the Cochrane Library.We included any study that assessed laser therapy’s effects on hypertrophic scars and keloids following median sternotomy.Studies were selected based on predefined inclusion criteria with-out publication year,design,or origin restrictions.Results:Six studies met the inclusion criteria,involving a total offive RCTs and one review.These studies primarily tested 585 and 595-nm pulsed dye laser(PDL)treatments,focusing on scar appearance,patient symptoms,and treatment satisfaction.Most studies reported significant improvements in scar height reduction and patient symptom relief after treatment,with mixed results for scar erythema and elasticity.Adverse events were generally mild and transient.Conclusions:Laser therapy offers a beneficial approach for improving the appearance and symptoms of hypertrophic scars and keloids post-median sternotomy.However,further research is necessary to optimize treatment parameters and explore the long-term psychosocial impacts of this therapy.This review highlights the need for more comprehensive studies to establish standardized treatment protocols and evaluate their effectiveness.展开更多
Solid-state samples based on modified polymethyl methacrylate （MPMMA） with methanol doped with the dye pyrromethene 650 （PM650） axe prepared. The effects of a volume percentage of methanol on the laser characteris...Solid-state samples based on modified polymethyl methacrylate （MPMMA） with methanol doped with the dye pyrromethene 650 （PM650） axe prepared. The effects of a volume percentage of methanol on the laser characteristics of the sample, including spectra properties, slope efficiency, photostability and tunable properties, are investigated. The broadband dye laser output wavelength is around 655 nm and a highest slope efficiency of 32.23% is achieved. Pumping the samples at a repetition rate of 5 Hz with a pulse energy of as high as 100 mJ （the fluence is 0.26 J/cm2）, the longest lifetime （168000 shots） is obtained in the sample （MMA：methanol=18：2）, and the corresponding normalized photostability reaches 109.19 GJ/mol. When the sample （MMA：methanol=18：2） is placed in a Shoshan-type oscilla- tor, the naxrow-linewidth operation is a continuous tuning range （up to 64 nm）. The results indicate that the laser characteristics of solid-state dyes can be greatly enhanced by using modified PMMA with methanol serving as the solid host.展开更多
Three dye-doped polymer rods in different matrices were synthesized in which weak hydrogen bond, strong hydrogen bond and covalent bond existed between the dye and the polymer chain. And the two-photon up-conversion...Three dye-doped polymer rods in different matrices were synthesized in which weak hydrogen bond, strong hydrogen bond and covalent bond existed between the dye and the polymer chain. And the two-photon up-conversion luminescent properties of HMASPS and HEASPS1 in three different microenvironments were studied.展开更多
Objective:Vascular lesions,such as port wine stain(PWS),lead to facial and psychological problems that require careful and timely treatments.This review aims to compare 2 mainstream methods pulsed dye laser(PDL)therap...Objective:Vascular lesions,such as port wine stain(PWS),lead to facial and psychological problems that require careful and timely treatments.This review aims to compare 2 mainstream methods pulsed dye laser(PDL)therapy and photodynamic therapy(PDT)for PWS.Methods:The Cochrane Library,PubMed,Embase,China National Knowledge Infrastructure(CNKI)Full-Text Chinese Database,and VIP Chinese Scientific Journals Database were searched for literature comparing PDL versus PDT in treating PWS with no dates set.Studies were eligible for inclusion if they were randomized,placebo-controlled or head-to-head trials published in either English or Chinese.The primary outcome was overall response rate judged by the physician/investigator-reported outcome scoring system.Adverse effects were also recorded.Review Manager was used to perform data synthesis.Cochrane risk-of-bias tool was used for methodological quality assessment.Retrospective studies were assessed based on the Newcastle-Ottawa Scale.The review protocol was registered in the International Prospective Register of Systematic Reviews(CRD42021243960).Results:Twelve studies met the inclusion criteria,among which 8 studies had the data necessary for the metaanalysis.Among the 8 studies,4 were retrospective studies with 1,075 patients.The other 4 were RCT studies with 532 randomized participants.Regarding the overall response rate of RCT studies,PDT demonstrated no significantly higher efficacy than PDL with risk ratio(RR)0.76(95%confidence interval[CI]0.48-1.20).Regarding purple types,the overall response rate of PDT was statistically significantly superior to that of PDL with RR of 0.47(95%CI:0.29-0.79).In terms of red types,PDT also manifested no significantly higher efficacy compared with PDL with RR of 0.85(95%CI:0.27-2.71).Conclusion:PDT is an effective and safe treatment for different types of PWS and was more effective than PDL in treating purple type of PWS.展开更多
Organic lasers hold great promise for enabling a new class of future optoelectronics.Consequently,the development of new organic semiconductors as gain media has recently been the subject of significant interest.The m...Organic lasers hold great promise for enabling a new class of future optoelectronics.Consequently,the development of new organic semiconductors as gain media has recently been the subject of significant interest.The molecular design principle based on Einstein coefficients has been validated for achieving high gain,with para-phenylene-vinylene scaffolds recognized as one of the most crucial frameworks.In this study,we develop a stilbene tetramer derivative,QSBCz,which has significantly increased conjugation compared to the highly efficient laser material,BSBCz,resulting in a remarkably high radiative decay rate and a large gain cross-section.However,we find that the optical losses play a significant role in the light amplification of QSBCz.Indeed,a comprehensive understanding and suppression of detrimental optical loss pathways throughout the lasing process are essential,whereas the losses intrinsically associated with molecules have not been well considered.Although host–vip systems are helpful in preventing concentration quenching in aggregated states,this study reveals notable losses when using common host molecules such as 4,4′-bis(9H-carbazol-9-yl)biphenyl(CBP)and mCBP.In contrast,a BSBCz derivative is successfully employed as the host,leading to improved stimulated emission amplification.These findings indicate the importance of host–emitter interactions in lasing properties and highlight the necessity to optimize host materials for developing new laser dyes.展开更多
The enhancement of stimulated Raman scattering (SRS) of acetone (C3H6O) and the generation of three color lasers in lasing dye rhodamine B (RB) were reported. The first-order Stokes wave (629.9 nm) of SRS of C3H6O was...The enhancement of stimulated Raman scattering (SRS) of acetone (C3H6O) and the generation of three color lasers in lasing dye rhodamine B (RB) were reported. The first-order Stokes wave (629.9 nm) of SRS of C3H6O was amplified by 2.83 times than that of pure C3H6O. At the same time, a dye laser of RB at the wavelength from 575 to 598 nm can be generated in a suitable concentration of RB between 3×10-5 and 2×10-4 mol/L. Thus the green pump laser, yellow dve laser, and red Stokes wave concurred.展开更多
Background Lower fluence of 585-nm flashlamp-pumped pulsed dye laser has been successfully used as a nonablative technique in the treatment of wrinkles. The objective of this study was to evaluate the effect of the pu...Background Lower fluence of 585-nm flashlamp-pumped pulsed dye laser has been successfully used as a nonablative technique in the treatment of wrinkles. The objective of this study was to evaluate the effect of the pulsed dye laser （585 nm） on the production of collagen and the mRNA expression of collagen related gene in fibroblasts in vitro. Methods Cultured fibroblasts were treated with a 585-nm flashlamp-pumped pulsed dye laser （ fluence 3 J/cm^2, 4 J/cm^2, spot size 7 mm, pulse duration 450 12s）. The production of collagen and the mRNA expression of transforming growth factor （TGF）-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type Ⅰ procollagen α1, α2 in fibroblasts were investigated by colorimetry or real time polymerase chain reaction. Results The production of collagen was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm^2 （P 〈0.001）. The mRNA expression of TGF- β1, SMAD2, SMAD3, SMAD4, SMAD7 and procollagen I was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm^2 （P 〈0.001）. No significant difference of mRNA expression of SMAD2, SMAD3, SMAD4, SMAD7 and type Ⅰ procollagen was found between controls and fibroblasts treated with pulsed dye laser with a fluence of 4 J/cm^2 （P 〉0.05）. Conclusions Lower fluence （3 J/cm^2） pulsed dye laser increased the collagen production in fibroblasts by up-regulating TGF-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type Ⅰ procollagen mRNA expression. These may be the reason it can be effectively used in the treatment of wrinkles.展开更多
1 Results The development of tuneable solid-state organic dye lasers is a subject of considerable interest and research activity.Compared to conventional liquid dye lasers they have the advantage of being free of solv...1 Results The development of tuneable solid-state organic dye lasers is a subject of considerable interest and research activity.Compared to conventional liquid dye lasers they have the advantage of being free of solvent handling,having small size,and being easy to operate.For high-performance solid-state dye lasers highly photo-stable dyes with low quantum yield of triplet formation and low triplet-triplet absorption cross-section in the lasing wavelength region are required.For solid state dye lasers ...展开更多
On the line of a previous work on the spectral properties of some of heteroaryl chalcone, the effect of medium acidity and photoreactivity of 3-（4-dimethylamino-phenyl）-l-（2,5-dimethyl-thiophen-3-yl）-propenone （D...On the line of a previous work on the spectral properties of some of heteroaryl chalcone, the effect of medium acidity and photoreactivity of 3-（4-dimethylamino-phenyl）-l-（2,5-dimethyl-thiophen-3-yl）-propenone （DDTP） has been investigated in dimethylformamide and in chloromethane solvents such as methylenechloride, chloroform and carbon tetrachloride. The dye solution （ca. 5×10^-4 mol·L^-1 in DMF） gives a good laser emission in the range 470 --560 nm with emission maximum at 515 nm upon pumping by nitrogen laser （λex=337.1 nm）. The laser parameters such as gain coefficient （a）, emission cross section （Cre） and half life energy （E1/2） at maximum laser emission are also determined.展开更多
文摘Polymers are a kind of attractive hosts for laser dyes due to their high transparency in both pumping and lasing ranges and superior optical homogeneity. In this paper solid dye samples based on polymethyl methacrylate （PMMA） doped with different concentrations of 1, 3, 5, 7, 8 -pentamethyl-2, 6-diethylpyrromethene-BF2 （PM567） are prepared. The absorption, fluorescence and lasing spectra of the samples are obtained. Wide absorption and fluorescence bands are obtained and a red shift of the maxima of the lasing emission spectra is observed. With the second-harmonic generation of Q-switched Nd：YAC laser （532 nm, -20 ns） pumping the samples longitudinally, the slope efficiencies of the samples are obtained. There is an optimal dye concentration for the highest slope efficiency when the pumping energy is lower than some typical value （-250 mJ）, and the highest slope efficiency 35.6% is obtained in the sample with a dye concentration of 2 × 10^-4 mol/L. Pumping the samples at a rate of 10Hz with a pulse energy as high as 200 mJ （the fluence is 0.2 J/cm^2）, the output energy drops to one-half of its initial value after approximate 15500 pulses and the normalized photostability is 5.17CJ/mol. A kind of solid dye laser which could have some applications is built.
文摘Laser action in methyl methacrylate （MMA） co-doped with sulforhodamine B and crystal violet dyes was investi- gated. The dye mixture was incorporated into a solid polymeric matrix and was pumped by a 532-nm Nd：YAG laser. Distributed feedback dye laser （DFDL） action was induced in the dye mixture using a prism arrangement both in the donor and acceptor regions by an energy transfer mechanism. Theoretically, the characteristics of acceptor and donor DFDLs, and the dependence of their pulse widths and output powers on acceptor-donor concentrations and pump power, were studied. Experimentally, the output energy of DFDL was measured at the emission peaks of donor and acceptor dyes for different pump powers and different acceptor-donor concentrations. Tuning of the output wavelength was achieved by varying the period of the gain modulation of the laser medium. The laser wavelength showed continuous tunability from 563 nm to 648 nm.
文摘In order to obtain a high output energy from a xenon lamp-pumped solid-state dye laser, homogeneities of laser mediums and flatnesses of medium faces with different processing treatments are discussed in the paper. The mediums without aging treatment, which are prepared by using a prepolymer process and have diamond-machined end faces to produce the required optical finish, give a highest laser output of 281.9 mJ with 0.215% slope efficiency at 2.0x 10^-4 mol/L. The best medium lifetime is 21 shots to 50% of original output equating 74.6 k J/liter.
文摘A new organic dye, trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methyl- pyridinium p-toluene sulfonate (HEASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HEASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 9.1% which is higher than that of known TPP laser dyes trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI) and trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) at the same experimental conditions.
文摘The solid-state medium containing pyrromethene 567 （PM567） in a polymethylmethacrylate polymer host is shown to lase under the flash lamp excitation. The experimental setup is an ordinary industrial product without special design. The bulk transmission losses, the output energy, and the other lasing properties are compared. The medium with the lowest transmission loss, measured to be 0.392 %/cm at 633 nm, gives a laser output of 130 mJ with a slope efficiency of 0.082%.
文摘Solid-state tunable dye laser materials developed by incorporation of stable laser dye molecules into solid host matrices like polymers, organically modified silicates (ORMOSILS) and porous sol-gel glasses. These materials have technical advantages such as compactness, better manageability and suitability for field measurement. The recent research work with highly porous sol-gel glasses having good transparency in UV-Near UV region used as solid host for solid-state dye laser materials has attracted a great deal of attention because of its high potential utility than polymers. Two different procedure’s are used for incorpoerating the Stilbine-3 (STB-3) laser dyes into porous sol-gel matrices such as dope or dip methods. In dope method dye is mixed at the sol state and drying is carried out afterward;while in dip method matrix is first prepared and the matrix is dipped in desired dye solution. After preparation of these dye embedded sol-gel glasses we studied their spectroscopic properties of using absorption and fluorescence spectroscopy. Along with spectroscopy properties, the studies for longevity or the shelf life and lasing action of these materials were carried out. Laser dye STB-3 incorporated in sol-gel glass samples shows the same result as in methanolic solution.
文摘To assess the effectiveness of the flashlamp- pumped pulsed dye laser (Photogeneca V, Synosure Corp, Boston, United States) in the treatment of port- wine stains. Methods. One hundred and ninety- four consecutive patients with port- wine stains were treated with a flashlamp- pumped pulsed dye laser in Peking Union Medical College Hospital from January 1998 to August 1999. Results. Of 194 patients who completed treatment, 56.2％ had more than 60％ fading of the lesion and only 6.7％ had less than 20％ fading. An average of 3.6 treatments were needed to achieve more than 60％ fading. The response was better in children than in adults, although the difference was not significant. Pigmentary change (usually transient) occurred in 3.1％ of patients. Conclusions. This study confirms the efficacy of the flashlamp- pumped pulsed dye laser in the treatment of port- wine stains in children and adults.
基金This tvork was supported by the grant for state key program of China by the National NaturalScience Foundation of China, al
文摘A new organic dye, trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate (HMASPS) has been synthesized and its structure has been determined. Pumped with a 1064 nm, 50 ps laser pulses, 0.05 mol/L HMASPS/DMF solution showed the two-photon pumped (TPP) output/input efficiency of 8.4% which is higher than that of trans-4-[p-(N-hydroxyethyl-N-methylamino) styryl]-N-methylpyridinium iodide (ASPI)(1) at the same pump level.
文摘Under high-excitation irradiance conditions to induce fluorescence, the dependence of photobleaching of Coumarin 307 （C307） and acriflavine （ACF） laser dyes in liquid and solid phases have been studied. A cw LD laser source of 1 mW and 407 nm wavelength was used as an exciting source. For one hour exposure time, it was found that the solid dye samples suffer photobleaching more than the liquid dye samples. This is because in liquid solutions the dye molecules can circulate during the irradiation, while the photobleaching is a serious problem when the dye is incorporated into solid matrix and cannot circulate.
文摘In 1967 the first work in solid state dye laser was performed by doping rhodamine dyes in Polymethylmethacrylate (PMMA) materials. Since then </span><span style="white-space:normal;"><span style="font-family:"">some</span></span><span style="white-space:normal;"><span style="font-family:""> materials like various types of polymers, co-polymers, poly</span></span><span style="white-space:normal;"><span style="font-family:""> </span></span><span style="white-space:normal;"><span style="font-family:"">composite glasses have been used as host matrices for doping different laser dyes. Polymers suffer from limited mechanical and thermal stability. Hence glasses can be the alternative hosts. However, because of high processing temperature leading to permanent destruction of dye molecules, </span></span><span style="white-space:normal;"><span style="font-family:"">the </span></span><span style="white-space:normal;"><span style="font-family:"">conventional glass preparation technique is not suitable for the introduction of organic laser dyes. This difficulty can be overcome by introducing the laser dye molecules in sol-gel glass which is prepared at low temperature. Recent work with sol-gel glasses shows that these glasses may prove to be better materials compared to polymeric materials because glasses being hard, best optically transparency in Near UV-UV and Visible region and show better photostability. In this research work we reported, comparative study of the photophysical properties of Coumarin-120 (C-120) belonging to 7-aminocoumarin family having two hydrogen atoms attached to the N atom at the 7-position, with Stilbene-3 (STB-3) in three types of HCl catalyzed SiO<sub>2</sub> sol-gel matrices prepared by Method I, Method II and Method III respectively.
文摘AIM:To document the prognosis of laser treatment in patients with exudative age-related macular degeneration(AMD).· METHODS:Efficacy of the intervention was evaluated using a before-after method.· RESULTS:A total of 392 eyes of 341 patients with exudative AMD were examined.77.6% had choroideal neovascularisation(CNV).Before the use of indocyanine green(ICG) angiography,occult CNV was detected in only 1.8% of the eyes,but after the use of ICG angiography,this increased to 19.5%(P<0.001).Of the 349 eyes which were followed up,visual acuity had remained stable in 68.2% of the eyes.There was a statistically significant relationship between localisation of lesion and visual acuity changes on pre-and post-laser treatment(P<0.001).Also there was a statistically significant relationship between localisation of lesion and recurrence(P<0.05).The recurrence was less in subfoveal lesions than that in juxtafoveal and extrafoveal lesions.· CONCLUSION:ICG angiography is highly important in the treatment of occult CNV.
文摘Background:Hypertrophic scars and keloids,common complications following median sternotomy for cardiac surgery,significantly impact patient quality of life due to their aesthetic and symptomatic burden.Recent advancements in laser therapy have made it a prominent option for managing these complex scars,yet a com-prehensive understanding of its efficacy is lacking.The aim of this scoping review is to explore the effects of laser therapy in managing hypertrophic scars and keloids after median sternotomy.Methods:This scoping review ana-lyzed studies up to February 2024 from databases including PubMed,EMBASE,CINAHL,Scopus,Web of Science,and the Cochrane Library.We included any study that assessed laser therapy’s effects on hypertrophic scars and keloids following median sternotomy.Studies were selected based on predefined inclusion criteria with-out publication year,design,or origin restrictions.Results:Six studies met the inclusion criteria,involving a total offive RCTs and one review.These studies primarily tested 585 and 595-nm pulsed dye laser(PDL)treatments,focusing on scar appearance,patient symptoms,and treatment satisfaction.Most studies reported significant improvements in scar height reduction and patient symptom relief after treatment,with mixed results for scar erythema and elasticity.Adverse events were generally mild and transient.Conclusions:Laser therapy offers a beneficial approach for improving the appearance and symptoms of hypertrophic scars and keloids post-median sternotomy.However,further research is necessary to optimize treatment parameters and explore the long-term psychosocial impacts of this therapy.This review highlights the need for more comprehensive studies to establish standardized treatment protocols and evaluate their effectiveness.
基金Project supported by the National Natural Science Foundation of China (Grant No.61008023)the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology,China (Grant No.HIT.NSRIF.2009009)
文摘Solid-state samples based on modified polymethyl methacrylate （MPMMA） with methanol doped with the dye pyrromethene 650 （PM650） axe prepared. The effects of a volume percentage of methanol on the laser characteristics of the sample, including spectra properties, slope efficiency, photostability and tunable properties, are investigated. The broadband dye laser output wavelength is around 655 nm and a highest slope efficiency of 32.23% is achieved. Pumping the samples at a repetition rate of 5 Hz with a pulse energy of as high as 100 mJ （the fluence is 0.26 J/cm2）, the longest lifetime （168000 shots） is obtained in the sample （MMA：methanol=18：2）, and the corresponding normalized photostability reaches 109.19 GJ/mol. When the sample （MMA：methanol=18：2） is placed in a Shoshan-type oscilla- tor, the naxrow-linewidth operation is a continuous tuning range （up to 64 nm）. The results indicate that the laser characteristics of solid-state dyes can be greatly enhanced by using modified PMMA with methanol serving as the solid host.
基金This work was supported by the grant for State Key Program of China.
文摘Three dye-doped polymer rods in different matrices were synthesized in which weak hydrogen bond, strong hydrogen bond and covalent bond existed between the dye and the polymer chain. And the two-photon up-conversion luminescent properties of HMASPS and HEASPS1 in three different microenvironments were studied.
基金supported by the Natural National Science Foundation of China(grant number:61835015)2021 National Society Journal Publishing Capability Improvement Program(Industry Development Services-27)+1 种基金the Big Data Research Support Fund of Chinese PLA General Hospital(2019MBD-011)CAMS Innovation Fund for Medical Sciences(2019-I2M-5-061).
文摘Objective:Vascular lesions,such as port wine stain(PWS),lead to facial and psychological problems that require careful and timely treatments.This review aims to compare 2 mainstream methods pulsed dye laser(PDL)therapy and photodynamic therapy(PDT)for PWS.Methods:The Cochrane Library,PubMed,Embase,China National Knowledge Infrastructure(CNKI)Full-Text Chinese Database,and VIP Chinese Scientific Journals Database were searched for literature comparing PDL versus PDT in treating PWS with no dates set.Studies were eligible for inclusion if they were randomized,placebo-controlled or head-to-head trials published in either English or Chinese.The primary outcome was overall response rate judged by the physician/investigator-reported outcome scoring system.Adverse effects were also recorded.Review Manager was used to perform data synthesis.Cochrane risk-of-bias tool was used for methodological quality assessment.Retrospective studies were assessed based on the Newcastle-Ottawa Scale.The review protocol was registered in the International Prospective Register of Systematic Reviews(CRD42021243960).Results:Twelve studies met the inclusion criteria,among which 8 studies had the data necessary for the metaanalysis.Among the 8 studies,4 were retrospective studies with 1,075 patients.The other 4 were RCT studies with 532 randomized participants.Regarding the overall response rate of RCT studies,PDT demonstrated no significantly higher efficacy than PDL with risk ratio(RR)0.76(95%confidence interval[CI]0.48-1.20).Regarding purple types,the overall response rate of PDT was statistically significantly superior to that of PDL with RR of 0.47(95%CI:0.29-0.79).In terms of red types,PDT also manifested no significantly higher efficacy compared with PDL with RR of 0.85(95%CI:0.27-2.71).Conclusion:PDT is an effective and safe treatment for different types of PWS and was more effective than PDL in treating purple type of PWS.
基金supported by the JSPS KAKENHI(Grants 23K04879,23H05406 and 23K20039,23H01977,23H04631)and the Inamori Foundation.
文摘Organic lasers hold great promise for enabling a new class of future optoelectronics.Consequently,the development of new organic semiconductors as gain media has recently been the subject of significant interest.The molecular design principle based on Einstein coefficients has been validated for achieving high gain,with para-phenylene-vinylene scaffolds recognized as one of the most crucial frameworks.In this study,we develop a stilbene tetramer derivative,QSBCz,which has significantly increased conjugation compared to the highly efficient laser material,BSBCz,resulting in a remarkably high radiative decay rate and a large gain cross-section.However,we find that the optical losses play a significant role in the light amplification of QSBCz.Indeed,a comprehensive understanding and suppression of detrimental optical loss pathways throughout the lasing process are essential,whereas the losses intrinsically associated with molecules have not been well considered.Although host–vip systems are helpful in preventing concentration quenching in aggregated states,this study reveals notable losses when using common host molecules such as 4,4′-bis(9H-carbazol-9-yl)biphenyl(CBP)and mCBP.In contrast,a BSBCz derivative is successfully employed as the host,leading to improved stimulated emission amplification.These findings indicate the importance of host–emitter interactions in lasing properties and highlight the necessity to optimize host materials for developing new laser dyes.
文摘The enhancement of stimulated Raman scattering (SRS) of acetone (C3H6O) and the generation of three color lasers in lasing dye rhodamine B (RB) were reported. The first-order Stokes wave (629.9 nm) of SRS of C3H6O was amplified by 2.83 times than that of pure C3H6O. At the same time, a dye laser of RB at the wavelength from 575 to 598 nm can be generated in a suitable concentration of RB between 3×10-5 and 2×10-4 mol/L. Thus the green pump laser, yellow dve laser, and red Stokes wave concurred.
文摘Background Lower fluence of 585-nm flashlamp-pumped pulsed dye laser has been successfully used as a nonablative technique in the treatment of wrinkles. The objective of this study was to evaluate the effect of the pulsed dye laser （585 nm） on the production of collagen and the mRNA expression of collagen related gene in fibroblasts in vitro. Methods Cultured fibroblasts were treated with a 585-nm flashlamp-pumped pulsed dye laser （ fluence 3 J/cm^2, 4 J/cm^2, spot size 7 mm, pulse duration 450 12s）. The production of collagen and the mRNA expression of transforming growth factor （TGF）-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type Ⅰ procollagen α1, α2 in fibroblasts were investigated by colorimetry or real time polymerase chain reaction. Results The production of collagen was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm^2 （P 〈0.001）. The mRNA expression of TGF- β1, SMAD2, SMAD3, SMAD4, SMAD7 and procollagen I was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm^2 （P 〈0.001）. No significant difference of mRNA expression of SMAD2, SMAD3, SMAD4, SMAD7 and type Ⅰ procollagen was found between controls and fibroblasts treated with pulsed dye laser with a fluence of 4 J/cm^2 （P 〉0.05）. Conclusions Lower fluence （3 J/cm^2） pulsed dye laser increased the collagen production in fibroblasts by up-regulating TGF-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type Ⅰ procollagen mRNA expression. These may be the reason it can be effectively used in the treatment of wrinkles.
文摘1 Results The development of tuneable solid-state organic dye lasers is a subject of considerable interest and research activity.Compared to conventional liquid dye lasers they have the advantage of being free of solvent handling,having small size,and being easy to operate.For high-performance solid-state dye lasers highly photo-stable dyes with low quantum yield of triplet formation and low triplet-triplet absorption cross-section in the lasing wavelength region are required.For solid state dye lasers ...
文摘On the line of a previous work on the spectral properties of some of heteroaryl chalcone, the effect of medium acidity and photoreactivity of 3-（4-dimethylamino-phenyl）-l-（2,5-dimethyl-thiophen-3-yl）-propenone （DDTP） has been investigated in dimethylformamide and in chloromethane solvents such as methylenechloride, chloroform and carbon tetrachloride. The dye solution （ca. 5×10^-4 mol·L^-1 in DMF） gives a good laser emission in the range 470 --560 nm with emission maximum at 515 nm upon pumping by nitrogen laser （λex=337.1 nm）. The laser parameters such as gain coefficient （a）, emission cross section （Cre） and half life energy （E1/2） at maximum laser emission are also determined.
