The first medical high intensity cyclotron CYCIAE-30 and its beam line for the isotope production were built in 1994 at China Institute of Atomic Energy.Now,an upgrading beam line system is designed based on the exist...The first medical high intensity cyclotron CYCIAE-30 and its beam line for the isotope production were built in 1994 at China Institute of Atomic Energy.Now,an upgrading beam line system is designed based on the existing beam line of CYCIAE-30 to transport the beam extracted from the cyclotron to a gas target for the new isotope production,including elements location design,optics simulation and magnet design.The machining and installation of all the elements are accomplished based on the design.The beam tuning is finished and the transmission of 96.5% is obtained.展开更多
Optical logic gates are elementary components for optical network and optical computing. In this paper, we propose a structure for AND, NAND, XNOR and NOR logic gates in the two dimensional photonic crystal which util...Optical logic gates are elementary components for optical network and optical computing. In this paper, we propose a structure for AND, NAND, XNOR and NOR logic gates in the two dimensional photonic crystal which utilizes the dispersion based self-collimation effect. The self-collimated beam is splitted by the line defect and interfered with other self-collimated beam. This interference may be constructive or destructive based on their phase difference. This phenomenon is employed to realize all-optical logic gates. The gates are demonstrated numerically by computing electromagnetic field distribution using the finite difference time domain （FDTD） method. The results ensure that this design can function as AND, NAND, XNOR and NOR logic gates. The size of the structure is about 10 μm× 10 μm which in turn results in an increase in the speed and all the gates are realized in the same configuration. The ON-OFF contrast ratio is about 6 dB.展开更多
The China Spallation Neutron Source(CSNS)is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW a...The China Spallation Neutron Source(CSNS)is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW at a repetition rate of 25 Hz.In this paper,we focus on the physical design of CSNS target station and neutron instruments.Under optimized design,the flat tungsten target and the compact target-moderator-reflector coupling enhance effective cold and thermal neutron output from moderators.Three wing-type moderators supply four different characteristics of neutrons to 19 beamlines primarily for neutron scattering applications.Layout of neutron instruments are conceptually planned for total 20 beamlines,the configuration and specification have been determined for three day-one neutron instruments.All designs are optimized for the Phase I of 100 kW with a upgradable capacity to 500 kW.展开更多
The performance of broadband polarizing beam splitters(PBSs) is sensitive to the incident angle.By taking account of the spectrum of the laser source and using the needle optimization method,a large acceptance angle P...The performance of broadband polarizing beam splitters(PBSs) is sensitive to the incident angle.By taking account of the spectrum of the laser source and using the needle optimization method,a large acceptance angle PBS for laser-based displays is designed.The average degrees of polarization in transmission and reflection can reach 0.989 and 0.980 for an acceptance angle of 13.6?in air using two materials,while better results of 0.993 and 0.989 for an acceptance angle of 14.8?in air are attained when three common materials are used.Both designs consist of 40 layers.展开更多
An effective design method of freeform micro lens array is presented for shaping varied laser beams into prescribed rectangular illumination. The variable separation mapping is applied to design concave freeform surfa...An effective design method of freeform micro lens array is presented for shaping varied laser beams into prescribed rectangular illumination. The variable separation mapping is applied to design concave freeform surfaces for constructing a freeform lens array. Several dedicated examples show that the designed freeform optical lens array can achieve a prescribed rectangular illumination pattern, especially without considering the initial states of incident laser beams. Both high collection efficiency and good spatial uniformity can be available simultaneously. Tolerance analysis is also performed to demonstrate that this optical device can well avoid fabricating difficulty in actual applications.展开更多
The properties of the linear chirped fiber grating （CFG） which is used in the true time delay unit of the optical beamforming networks （OBFNs） are studied intensively through theoretical analyses and numerical cal...The properties of the linear chirped fiber grating （CFG） which is used in the true time delay unit of the optical beamforming networks （OBFNs） are studied intensively through theoretical analyses and numerical calculations. It is concluded that the dispersion of the CFG is equal to 1/（3Gc）, where G is the chirp coefficient of CFG and c is the light speed. Based on this relationship, a simplified designing process of a CFG which satisfies the requirements of the O13 FN is given. The simula- tion results are coincident with the theoretical conclusions.展开更多
In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) ...In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) is obtained from the scalar wave equation. The transition waveguide is combined with S-type bend branch waveguide for the M-Z EO modulator in the branch waveguide. The effects of structure parameters such as ridge width,length of the branch waveguide and interferometer spacing on the transmission loss are systematically studied by using the semi-vector FD-BPM method. The structure is optimized as an S-sine bend branch waveguide,with rib width w=7μm,length of branch waveguide L=1200μm and interferometer spacing G=22 μm. The results show that the optimized structure can reduce transmission loss to 0.083 dB,which have a certain reference value to the design of optical waveguide in M-Z polymer modulator.展开更多
A novel fiber laser spectral beam combining scheme based on a concave grating is presented.The principle of the presented system is analyzed,and a concave grating with blazed structure for spectral beam combining is d...A novel fiber laser spectral beam combining scheme based on a concave grating is presented.The principle of the presented system is analyzed,and a concave grating with blazed structure for spectral beam combining is designed.The combining potential of the system is analyzed,and the results show that 39 Yb-doped fiber laser can be spectrally beam combined via the designed system.By using scalar diffraction theory,the combining effect of the system is analyzed.The results show that the diffraction efficiency of the designed concave grating is higher than 72% over the whole gain bandwidth,and the combining efficiency is 73.4%.With output power of 1 kW for individual fiber laser,combined power of 28.6 kW can be achieved.展开更多
文摘The first medical high intensity cyclotron CYCIAE-30 and its beam line for the isotope production were built in 1994 at China Institute of Atomic Energy.Now,an upgrading beam line system is designed based on the existing beam line of CYCIAE-30 to transport the beam extracted from the cyclotron to a gas target for the new isotope production,including elements location design,optics simulation and magnet design.The machining and installation of all the elements are accomplished based on the design.The beam tuning is finished and the transmission of 96.5% is obtained.
文摘Optical logic gates are elementary components for optical network and optical computing. In this paper, we propose a structure for AND, NAND, XNOR and NOR logic gates in the two dimensional photonic crystal which utilizes the dispersion based self-collimation effect. The self-collimated beam is splitted by the line defect and interfered with other self-collimated beam. This interference may be constructive or destructive based on their phase difference. This phenomenon is employed to realize all-optical logic gates. The gates are demonstrated numerically by computing electromagnetic field distribution using the finite difference time domain （FDTD） method. The results ensure that this design can function as AND, NAND, XNOR and NOR logic gates. The size of the structure is about 10 μm× 10 μm which in turn results in an increase in the speed and all the gates are realized in the same configuration. The ON-OFF contrast ratio is about 6 dB.
基金supported by the National Large Facility Project from the National Development and Reform Commissionthe CSNS R&D funds from CAS,Guangdong Province,and Dongguan Citythe National Basic Research Program of China(Grant No.2010CB833102)
文摘The China Spallation Neutron Source(CSNS)is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW at a repetition rate of 25 Hz.In this paper,we focus on the physical design of CSNS target station and neutron instruments.Under optimized design,the flat tungsten target and the compact target-moderator-reflector coupling enhance effective cold and thermal neutron output from moderators.Three wing-type moderators supply four different characteristics of neutrons to 19 beamlines primarily for neutron scattering applications.Layout of neutron instruments are conceptually planned for total 20 beamlines,the configuration and specification have been determined for three day-one neutron instruments.All designs are optimized for the Phase I of 100 kW with a upgradable capacity to 500 kW.
基金supported by the National Natural Science Foundation of China (No.50802080)the Natural Science Foundation of Fujian Province (No.2010J01349)
文摘The performance of broadband polarizing beam splitters(PBSs) is sensitive to the incident angle.By taking account of the spectrum of the laser source and using the needle optimization method,a large acceptance angle PBS for laser-based displays is designed.The average degrees of polarization in transmission and reflection can reach 0.989 and 0.980 for an acceptance angle of 13.6?in air using two materials,while better results of 0.993 and 0.989 for an acceptance angle of 14.8?in air are attained when three common materials are used.Both designs consist of 40 layers.
基金supported by the National Natural Science Foundation of China(No.61405037)the Science and Technology Project of Fujian Province(No.2015H4014)
文摘An effective design method of freeform micro lens array is presented for shaping varied laser beams into prescribed rectangular illumination. The variable separation mapping is applied to design concave freeform surfaces for constructing a freeform lens array. Several dedicated examples show that the designed freeform optical lens array can achieve a prescribed rectangular illumination pattern, especially without considering the initial states of incident laser beams. Both high collection efficiency and good spatial uniformity can be available simultaneously. Tolerance analysis is also performed to demonstrate that this optical device can well avoid fabricating difficulty in actual applications.
基金supported by the National Natural Science Foundation of China (No.60702005)the Hi-Tech Research and Development Program of China (Nos.2009AA01Z218 and 2009AA01Z255)+1 种基金the National Basic Research Program of China (973 Program) (Nos.2010CB328202and 2010CB328204)the Fundamental Research Funds for the Central
文摘The properties of the linear chirped fiber grating （CFG） which is used in the true time delay unit of the optical beamforming networks （OBFNs） are studied intensively through theoretical analyses and numerical calculations. It is concluded that the dispersion of the CFG is equal to 1/（3Gc）, where G is the chirp coefficient of CFG and c is the light speed. Based on this relationship, a simplified designing process of a CFG which satisfies the requirements of the O13 FN is given. The simula- tion results are coincident with the theoretical conclusions.
基金supported by the National High Technology Research and Development Program of China (No.2009AA03Z413)
文摘In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) is obtained from the scalar wave equation. The transition waveguide is combined with S-type bend branch waveguide for the M-Z EO modulator in the branch waveguide. The effects of structure parameters such as ridge width,length of the branch waveguide and interferometer spacing on the transmission loss are systematically studied by using the semi-vector FD-BPM method. The structure is optimized as an S-sine bend branch waveguide,with rib width w=7μm,length of branch waveguide L=1200μm and interferometer spacing G=22 μm. The results show that the optimized structure can reduce transmission loss to 0.083 dB,which have a certain reference value to the design of optical waveguide in M-Z polymer modulator.
基金supported by the National Natural Science Foundation of China(No.60678018)
文摘A novel fiber laser spectral beam combining scheme based on a concave grating is presented.The principle of the presented system is analyzed,and a concave grating with blazed structure for spectral beam combining is designed.The combining potential of the system is analyzed,and the results show that 39 Yb-doped fiber laser can be spectrally beam combined via the designed system.By using scalar diffraction theory,the combining effect of the system is analyzed.The results show that the diffraction efficiency of the designed concave grating is higher than 72% over the whole gain bandwidth,and the combining efficiency is 73.4%.With output power of 1 kW for individual fiber laser,combined power of 28.6 kW can be achieved.
