Temporal contrast directly affects the interaction between ultraintense and ultrashort pulse lasers with matter.Seed laser sources with broad bandwidth and high temporal contrast are significant for overall temporal c...Temporal contrast directly affects the interaction between ultraintense and ultrashort pulse lasers with matter.Seed laser sources with broad bandwidth and high temporal contrast are significant for overall temporal contrast enhancement.The technique of cascaded nonlinear processes with optical parametric amplification and second-harmonic generation is demonstrated for high temporal contrast seed source generation.Within 40 ps before the main pulse,the temporal contrast reaches over 10^(11).The pulse energy and duration of the high-contrast pulse are 112μJ and 70 fs,respectively.Considering its high beam quality and stability,this laser source can serve as a high-quality seed for Nd:glass-based ultraintense and ultrashort pulse laser facilities.展开更多
We demonstrate the simultaneous temporal contrast improvement and pulse compression of a Yb-doped femtosecond laser via nonlinear elliptical polarization rotation in a solid state multi-pass cell.The temporal contrast...We demonstrate the simultaneous temporal contrast improvement and pulse compression of a Yb-doped femtosecond laser via nonlinear elliptical polarization rotation in a solid state multi-pass cell.The temporal contrast is improved to 109,while the pulse is shortened from 181 to 36 fs,corresponding to a compression factor of 5.The output beam features excellent beam quality with M^(2) values of 1.18×1.16.The total efficiency of the contrast enhancement system exceeds 50%.This technique will have wide applications in high temporal contrast ultra-intense femtosecond lasers.展开更多
To separate and concentrate NH4＋ and PO43 from the synthetic wastewater to the concentrated solution through a novel electrochemical reactor with circulated anode and cathode using the difference of the concentration...To separate and concentrate NH4＋ and PO43 from the synthetic wastewater to the concentrated solution through a novel electrochemical reactor with circulated anode and cathode using the difference of the concentration between electrode chamber and middle chamber.In recent years, the research on electrochemical processes have been focused on phosphate and ammonium removal and recovery. Among the wide range of possibilities with regards to electrochemical processes, capacitive deionization （CDI） saves the most energy while at the same time does not have continuity and selectivity. In this study, a new electrochemical reactor with electrolyte cyclic flowing in the electrode chambers was constructed to separate and concentrate phosphate and ammonium continuously and selectively from wastewater, based on the principle of CDI. At the concentration ratio of NaCI solution between the electrode chambers and the middle chamber （r） of 25 to 1, phosphate and ammonium in concentration level of domestic wastewater can be removed and recovered continuously and selectively as struvite. Long-term operation also indicated the ability to continuously repeat the reaction and verified sustained stability. Further, the selective recovery at the certain r could also be available to similar technologies for recovering other kinds of substances.展开更多
基金supported by the National Key R&D Program of China(2017YFE0123700)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB1603)+5 种基金the National Natural Science Foundation of China(61925507,62075227,12004402)the Program of Shanghai Academic/Technology Research Leader(18XD1404200)the Shanghai Municipal Science and Technology Major Project(2017SHZDZX02)the Youth Innovation Promotion Association CAS(2020248)the Shanghai Sailing Program(20YF1455000)the Shanghai Rising-Star Program(21QA1410200)
文摘Temporal contrast directly affects the interaction between ultraintense and ultrashort pulse lasers with matter.Seed laser sources with broad bandwidth and high temporal contrast are significant for overall temporal contrast enhancement.The technique of cascaded nonlinear processes with optical parametric amplification and second-harmonic generation is demonstrated for high temporal contrast seed source generation.Within 40 ps before the main pulse,the temporal contrast reaches over 10^(11).The pulse energy and duration of the high-contrast pulse are 112μJ and 70 fs,respectively.Considering its high beam quality and stability,this laser source can serve as a high-quality seed for Nd:glass-based ultraintense and ultrashort pulse laser facilities.
基金supported by the National Key R&D Program of China(No.2017YFE0123700)the National Natural Science Foundation of China(Nos.61925507 and 62075227)+1 种基金the Shanghai Rising-Star Program(No.21QA1410200)the Youth Innovation Promotion Association CAS(No.2020248).
文摘We demonstrate the simultaneous temporal contrast improvement and pulse compression of a Yb-doped femtosecond laser via nonlinear elliptical polarization rotation in a solid state multi-pass cell.The temporal contrast is improved to 109,while the pulse is shortened from 181 to 36 fs,corresponding to a compression factor of 5.The output beam features excellent beam quality with M^(2) values of 1.18×1.16.The total efficiency of the contrast enhancement system exceeds 50%.This technique will have wide applications in high temporal contrast ultra-intense femtosecond lasers.
基金This research was supported by the Key Program of the National Natural Science Foundation of China （Grant Nos. 51238004 ＆ 21521064）.
文摘To separate and concentrate NH4＋ and PO43 from the synthetic wastewater to the concentrated solution through a novel electrochemical reactor with circulated anode and cathode using the difference of the concentration between electrode chamber and middle chamber.In recent years, the research on electrochemical processes have been focused on phosphate and ammonium removal and recovery. Among the wide range of possibilities with regards to electrochemical processes, capacitive deionization （CDI） saves the most energy while at the same time does not have continuity and selectivity. In this study, a new electrochemical reactor with electrolyte cyclic flowing in the electrode chambers was constructed to separate and concentrate phosphate and ammonium continuously and selectively from wastewater, based on the principle of CDI. At the concentration ratio of NaCI solution between the electrode chambers and the middle chamber （r） of 25 to 1, phosphate and ammonium in concentration level of domestic wastewater can be removed and recovered continuously and selectively as struvite. Long-term operation also indicated the ability to continuously repeat the reaction and verified sustained stability. Further, the selective recovery at the certain r could also be available to similar technologies for recovering other kinds of substances.
