A simple and compact linear resonator green laser at 532 nm is generated by intracavity frequencydoubling of a diode-side-pumped acousto-optically（AO）Q-switched Nd：YAG laser at 1064 nm.Two acoustooptic Q-switches w...A simple and compact linear resonator green laser at 532 nm is generated by intracavity frequencydoubling of a diode-side-pumped acousto-optically（AO）Q-switched Nd：YAG laser at 1064 nm.Two acoustooptic Q-switches were placed orthogonally with each other to improve the hold-off capacity.As high as 214 W of continuous-wave（CW）and 154 W of quasi-continuous-wave（QCW）output power at 1064 nm were obtained when the pumping power was 1598 W.The type I phase-matched BBO crystal was used as the nonlinear medium in the second harmonic generation.A green laser with an average output power of 37 W was obtained at a repetition rate of 20 kHz and a pulse width of 54 ns,which corresponds to pulse energy of 1.85 mJ per pulse and a peak power34.26 kW,respectively.展开更多
A wideband 2×2 sequential-phase fed circularly polarized(CP)microstrip antenna array(MAA)with sequentially rotated elements is proposed.Firstly,the antenna element loaded with shorting pins is studied as compared...A wideband 2×2 sequential-phase fed circularly polarized(CP)microstrip antenna array(MAA)with sequentially rotated elements is proposed.Firstly,the antenna element loaded with shorting pins is studied as compared to the traditional counterpart.Then,a feeding network is designed to be connected together in a sequential rotation manner,resulting in forming a four-port network to allow symmetrical positioning of CP microstrip patch elements.After that,straight strips are added to the feeding network in order to increase the distance and reduce coupling between array elements.They also play a role in improving the impedance matching of the array.Finally,the proposed antenna array is designed and simulated.The results are presented that its impedance bandwidth is about 36.3%at 24.1~34.8 GHz for|S_(11)|<10 dB and axial-ratio(AR)bandwidth is about 20.4%at 24.2~29.7 GHz for AR【3 dB.Besides,a peak gain of 11.1 dBic is simulated over the operating frequency range,which is significantly improved compared to the classic and existing works.展开更多
基金supported by the Beijing Engineering Technology Research Center of All-Solid-State Lasers Advanced Manufacturingthe National High Technology Research and Development Program of China(No.2014AA032607)the National Natural Science Foundation of China(Nos.61404135,61405186,61308032,61308033)
文摘A simple and compact linear resonator green laser at 532 nm is generated by intracavity frequencydoubling of a diode-side-pumped acousto-optically（AO）Q-switched Nd：YAG laser at 1064 nm.Two acoustooptic Q-switches were placed orthogonally with each other to improve the hold-off capacity.As high as 214 W of continuous-wave（CW）and 154 W of quasi-continuous-wave（QCW）output power at 1064 nm were obtained when the pumping power was 1598 W.The type I phase-matched BBO crystal was used as the nonlinear medium in the second harmonic generation.A green laser with an average output power of 37 W was obtained at a repetition rate of 20 kHz and a pulse width of 54 ns,which corresponds to pulse energy of 1.85 mJ per pulse and a peak power34.26 kW,respectively.
基金This work was supported by National Natural Science Foundation of China under Grant Nos.61801348 and 61971475University of Macao under Grant Nos.MYRG2017-00007-FST,MYRG2018-00073-FST,and CPG2020-00003-FSTState Key Laboratory of Millimeter Waves under Contract K202031.
文摘A wideband 2×2 sequential-phase fed circularly polarized(CP)microstrip antenna array(MAA)with sequentially rotated elements is proposed.Firstly,the antenna element loaded with shorting pins is studied as compared to the traditional counterpart.Then,a feeding network is designed to be connected together in a sequential rotation manner,resulting in forming a four-port network to allow symmetrical positioning of CP microstrip patch elements.After that,straight strips are added to the feeding network in order to increase the distance and reduce coupling between array elements.They also play a role in improving the impedance matching of the array.Finally,the proposed antenna array is designed and simulated.The results are presented that its impedance bandwidth is about 36.3%at 24.1~34.8 GHz for|S_(11)|<10 dB and axial-ratio(AR)bandwidth is about 20.4%at 24.2~29.7 GHz for AR【3 dB.Besides,a peak gain of 11.1 dBic is simulated over the operating frequency range,which is significantly improved compared to the classic and existing works.
