Novel polymer distributed feedback (DFB) gratings axe fabricated based on photopolymerization to reduce lasing threshold of polymer lasers. A photopolymer formulation sensitive to 355-nm ultraviolet (UV) light is ...Novel polymer distributed feedback (DFB) gratings axe fabricated based on photopolymerization to reduce lasing threshold of polymer lasers. A photopolymer formulation sensitive to 355-nm ultraviolet (UV) light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process. A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012. The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.展开更多
We demonstrate the generation of a Q-switching pulse train in an erbium-doped fiber laser (EDFL) cavity using a newly developed cadmium selenide (CdSe) based saturable absorber (SA). The SA is obtained by embedd...We demonstrate the generation of a Q-switching pulse train in an erbium-doped fiber laser (EDFL) cavity using a newly developed cadmium selenide (CdSe) based saturable absorber (SA). The SA is obtained by embedding CdSe nanomaterials into a polymethyl methacrylate (PMMA) microfiber. It is incorporated into an EDFL cavity to generate a Q-switched laser operating at 1533.6nm. The repetition rates of the produced pulse train are tunable within 37–64kHz as the pump power is varied from 34mW to 74mW. The corresponding pulse width reduces from 7.96μs to 4.84μs, and the maximum pulse energy of 1.16nJ is obtained at the pump power of 74mW.展开更多
In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)_5CH_3I and W(CO)_4I_2 produced from UV laser photolysis of W (CO)_6 in CH_3I, I_2—C_6H_...In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)_5CH_3I and W(CO)_4I_2 produced from UV laser photolysis of W (CO)_6 in CH_3I, I_2—C_6H_6 and CHI_3—C_6H_6 respectively was studied. The effects of laser energy, laser irradiation time and lifetime of catalyst on the polymerization of phenylacetylene were discussed. The photoproducts of W (CO)_6 in CH_3I, I2—C_6H_6 and CHI_3—C_6I_6 were determined by IR spectra. The structures of polyphenylacetylene obtained by W (CO)_5CH_3I and W (CO)_4I_2 catalysts were characterized by IR spectra and ~1H NMR spectra.展开更多
Compound eyes are unique optical imaging systems that consist of numerous separate light-sensitive units(ommatidia).Attempts have been made to produce artificial compound eyes via advanced 3 D nanotechnologies.Among t...Compound eyes are unique optical imaging systems that consist of numerous separate light-sensitive units(ommatidia).Attempts have been made to produce artificial compound eyes via advanced 3 D nanotechnologies.Among them,femtosecond laser direct writing(FsLDW)technology has emerged as an effective strategy due to its distinct advantages in 3 D designable and high precision fabrication capability.However,the point-by-point scanning process results in a very low fabrication efficiency,limiting the practical applications of the FsLDW technology.To solve this problem,we propose a high-efficiency method for the mass production of 3 D artificial compound eyes using a photopolymer template fabricated by FsLDW.The resultant 3 D SU-8 compound eye templates could be used to replicate polydimethylsiloxane(PDMS)compound eyes many times(over 50 times)with a highly improved efficiency(nearly 20 times higher than the efficiency of direct fabrication using the point-by-point FsLDW).The PDMS replicas showed good focusing and imaging performances.We anticipate that this method may serve as an enabler for the mass production of 3 D artificial compound eyes and promote their practical applications in the near future.展开更多
The use of a CO2 laser system for fabrication of microfluidic chip on polymethyl methacrylate (PMMA) is presented to reduce fabrication cost and time of chip. The grooving process of the laser system and a model for...The use of a CO2 laser system for fabrication of microfluidic chip on polymethyl methacrylate (PMMA) is presented to reduce fabrication cost and time of chip. The grooving process of the laser system and a model for the depth of microchannels are investigated. The relations between the depth of laser-cut channels and the laser beam power, velocity or the number of passes of the beam along the same channel are evaluated. In the experiments, the laser beam power varies from 0 to 50 W, the laser beam scanning velocity varies from 0 to 1 000 mm/s and the passes vary in the range of 1 to 10 times. Based on the principle of conservation of energy, the influence of the laser beam velocity, the laser power and the number of groove passes are examine. Considering the grooving interval energy loss, a modified mathematical model has been obtained and experimental data show good agreement with the theoretical model. This approach provides a simple way of predicting groove depths. The system provides a cost alternative of the other methods and it is especially useful on research work of rnicrofluidic prototyping due to the short cycle time of production.展开更多
Dust-free semidilute and concentrated polystyrene(PS)solutions in different solvents were prepared by slow evaporation and in situ anionic polymerization,which removes the effects of troublesome artifacts such as dust...Dust-free semidilute and concentrated polystyrene(PS)solutions in different solvents were prepared by slow evaporation and in situ anionic polymerization,which removes the effects of troublesome artifacts such as dust contamination and concentration gradient.The dynamics was reexamined by a combination of static and dynamic laser light scattering.In benzene and toluene(good solvents for PS),only one fast diffusive mode of polymer chains can be observed when the concentration(c)is up to 20%,which is attribut...展开更多
A novel two photon photoninitiated polymerization is reported. The results of the study show that the two photon polymerization of TMPTMA can be initiated by means of 4,4 bis(di n butylamino) E stiebene(BDBAS) under...A novel two photon photoninitiated polymerization is reported. The results of the study show that the two photon polymerization of TMPTMA can be initiated by means of 4,4 bis(di n butylamino) E stiebene(BDBAS) under 600 nm strong laser. The light source that we used for the two photon polymerization is a YAG pumped dye laser whose oscillating wavelength repetition rate and single pulse energy are 600 nm, 10 ns and 15 mJ, respectively. The peak power density of radiation light tight focused by means of bojective lens is 3.8 GW/cm 2. The relative mechanism of the polymerization is discussed. [WT5HZ]展开更多
采用紫外光引发模式制备了甲基丙烯酸酯类毛细管整体柱,通过控制光照精确地控制了柱床的长度及边界。将环糊精(-βCD)共价连接到了高分子聚合物链上作为手性选择剂,在碱性环境下以液相色谱模式实现了在人体的代谢反应中有着重要作用的F...采用紫外光引发模式制备了甲基丙烯酸酯类毛细管整体柱,通过控制光照精确地控制了柱床的长度及边界。将环糊精(-βCD)共价连接到了高分子聚合物链上作为手性选择剂,在碱性环境下以液相色谱模式实现了在人体的代谢反应中有着重要作用的FITC标记的D,L-苯丙氨酸的分离,理论柱效125 000 p lates/m,并分析了流动相性质对分离的影响。展开更多
文摘Novel polymer distributed feedback (DFB) gratings axe fabricated based on photopolymerization to reduce lasing threshold of polymer lasers. A photopolymer formulation sensitive to 355-nm ultraviolet (UV) light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process. A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012. The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.
文摘We demonstrate the generation of a Q-switching pulse train in an erbium-doped fiber laser (EDFL) cavity using a newly developed cadmium selenide (CdSe) based saturable absorber (SA). The SA is obtained by embedding CdSe nanomaterials into a polymethyl methacrylate (PMMA) microfiber. It is incorporated into an EDFL cavity to generate a Q-switched laser operating at 1533.6nm. The repetition rates of the produced pulse train are tunable within 37–64kHz as the pump power is varied from 34mW to 74mW. The corresponding pulse width reduces from 7.96μs to 4.84μs, and the maximum pulse energy of 1.16nJ is obtained at the pump power of 74mW.
文摘In this paper, the stereoselective homogeneous catalysis polymerization of phenylacetylene by using two kinds of catalysts W(CO)_5CH_3I and W(CO)_4I_2 produced from UV laser photolysis of W (CO)_6 in CH_3I, I_2—C_6H_6 and CHI_3—C_6H_6 respectively was studied. The effects of laser energy, laser irradiation time and lifetime of catalyst on the polymerization of phenylacetylene were discussed. The photoproducts of W (CO)_6 in CH_3I, I2—C_6H_6 and CHI_3—C_6I_6 were determined by IR spectra. The structures of polyphenylacetylene obtained by W (CO)_5CH_3I and W (CO)_4I_2 catalysts were characterized by IR spectra and ~1H NMR spectra.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.#61935008,#61590930,#61775078,and#61605055
文摘Compound eyes are unique optical imaging systems that consist of numerous separate light-sensitive units(ommatidia).Attempts have been made to produce artificial compound eyes via advanced 3 D nanotechnologies.Among them,femtosecond laser direct writing(FsLDW)technology has emerged as an effective strategy due to its distinct advantages in 3 D designable and high precision fabrication capability.However,the point-by-point scanning process results in a very low fabrication efficiency,limiting the practical applications of the FsLDW technology.To solve this problem,we propose a high-efficiency method for the mass production of 3 D artificial compound eyes using a photopolymer template fabricated by FsLDW.The resultant 3 D SU-8 compound eye templates could be used to replicate polydimethylsiloxane(PDMS)compound eyes many times(over 50 times)with a highly improved efficiency(nearly 20 times higher than the efficiency of direct fabrication using the point-by-point FsLDW).The PDMS replicas showed good focusing and imaging performances.We anticipate that this method may serve as an enabler for the mass production of 3 D artificial compound eyes and promote their practical applications in the near future.
基金This project is supported by National Hi-tech Research and Development Program of China (863 Program, No.2002AA421150)Specialized Research Fund for the Doctoral Program of Higher Education of China (No.20030335091).
文摘The use of a CO2 laser system for fabrication of microfluidic chip on polymethyl methacrylate (PMMA) is presented to reduce fabrication cost and time of chip. The grooving process of the laser system and a model for the depth of microchannels are investigated. The relations between the depth of laser-cut channels and the laser beam power, velocity or the number of passes of the beam along the same channel are evaluated. In the experiments, the laser beam power varies from 0 to 50 W, the laser beam scanning velocity varies from 0 to 1 000 mm/s and the passes vary in the range of 1 to 10 times. Based on the principle of conservation of energy, the influence of the laser beam velocity, the laser power and the number of groove passes are examine. Considering the grooving interval energy loss, a modified mathematical model has been obtained and experimental data show good agreement with the theoretical model. This approach provides a simple way of predicting groove depths. The system provides a cost alternative of the other methods and it is especially useful on research work of rnicrofluidic prototyping due to the short cycle time of production.
基金the Chinese Academy of Sciences(CAS)Special Grant(No.KJCX2-SW-H14)the National Natural Scientific Foundation of China(Nos.20534020 and 20574065)the Hong Kong Special Administration Region(HKSAR)Earmarked Project(CUHK4025/04P,2160242)
文摘Dust-free semidilute and concentrated polystyrene(PS)solutions in different solvents were prepared by slow evaporation and in situ anionic polymerization,which removes the effects of troublesome artifacts such as dust contamination and concentration gradient.The dynamics was reexamined by a combination of static and dynamic laser light scattering.In benzene and toluene(good solvents for PS),only one fast diffusive mode of polymer chains can be observed when the concentration(c)is up to 20%,which is attribut...
基金Projects(51934009, 52074353) supported by the National Natural Science Foundation of ChinaProject(20225199K001) supported by the Zijin Mining State Key Laboratory of Biometallurgy Open Fund,China。
文摘A novel two photon photoninitiated polymerization is reported. The results of the study show that the two photon polymerization of TMPTMA can be initiated by means of 4,4 bis(di n butylamino) E stiebene(BDBAS) under 600 nm strong laser. The light source that we used for the two photon polymerization is a YAG pumped dye laser whose oscillating wavelength repetition rate and single pulse energy are 600 nm, 10 ns and 15 mJ, respectively. The peak power density of radiation light tight focused by means of bojective lens is 3.8 GW/cm 2. The relative mechanism of the polymerization is discussed. [WT5HZ]
文摘采用紫外光引发模式制备了甲基丙烯酸酯类毛细管整体柱,通过控制光照精确地控制了柱床的长度及边界。将环糊精(-βCD)共价连接到了高分子聚合物链上作为手性选择剂,在碱性环境下以液相色谱模式实现了在人体的代谢反应中有着重要作用的FITC标记的D,L-苯丙氨酸的分离,理论柱效125 000 p lates/m,并分析了流动相性质对分离的影响。