As a natural character of high gain flee electron laser (FEL),harmonic radiation is regarded as the natural extensions to short wavelengths.In high gain harmonic generation (HGHG) scheme,harmonic evolution may be attr...As a natural character of high gain flee electron laser (FEL),harmonic radiation is regarded as the natural extensions to short wavelengths.In high gain harmonic generation (HGHG) scheme,harmonic evolution may be attributed to the initial harmonic bunching,self amplification of the harmonic radiation,electron beam strongly bunched by the fundamental radiation,the faster longitudinal dynamics and the fundamental synchrotron oscillation.It is more complex than harmonic evolution in other FEL schemes.In this paper,via theoretical analyses and three dimensional simulations,a general description of different aspects of harmonic evolution in the HGHG process is presented.展开更多
By choosing parameters in the modulator, the dispersive section and the seed laser, the spatial bunching of the electron beam can be correlated to the n-th harmonic of the radiator radiation, instead of the fundamenta...By choosing parameters in the modulator, the dispersive section and the seed laser, the spatial bunching of the electron beam can be correlated to the n-th harmonic of the radiator radiation, instead of the fundamental radiation in conventional high-gain harmonic generation (HGHG). Thus, the radiator undulator is operated at high harmonic mode. In this paper, the possibility of harmonic operation of Shanghai deep ultraviolet (SDUV) free electron laser (FEL) is studied. Discussions on the principle of harmonic operation, the simulation code development, the simulation results, and the proposed experimental procedure for verification of harmonic operation at the SDUV FEL are also presented.展开更多
In high gain harmonic generation （HGHG） free electron laser （FEL）, with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of th...In high gain harmonic generation （HGHG） free electron laser （FEL）, with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation （HO） mode. In this paper, we investigate HO of HGHG FEL. Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy.展开更多
基金supported by the Key Project for Promoting Fundamental Research in China (Grant No.2002CB713600)
文摘As a natural character of high gain flee electron laser (FEL),harmonic radiation is regarded as the natural extensions to short wavelengths.In high gain harmonic generation (HGHG) scheme,harmonic evolution may be attributed to the initial harmonic bunching,self amplification of the harmonic radiation,electron beam strongly bunched by the fundamental radiation,the faster longitudinal dynamics and the fundamental synchrotron oscillation.It is more complex than harmonic evolution in other FEL schemes.In this paper,via theoretical analyses and three dimensional simulations,a general description of different aspects of harmonic evolution in the HGHG process is presented.
基金Key Project for Promoting Fundamental Research in China (Grant No. 2002CB713600)
文摘By choosing parameters in the modulator, the dispersive section and the seed laser, the spatial bunching of the electron beam can be correlated to the n-th harmonic of the radiator radiation, instead of the fundamental radiation in conventional high-gain harmonic generation (HGHG). Thus, the radiator undulator is operated at high harmonic mode. In this paper, the possibility of harmonic operation of Shanghai deep ultraviolet (SDUV) free electron laser (FEL) is studied. Discussions on the principle of harmonic operation, the simulation code development, the simulation results, and the proposed experimental procedure for verification of harmonic operation at the SDUV FEL are also presented.
基金Supported by Major State Basic Research Development Program of China(2002CB713600)
文摘In high gain harmonic generation （HGHG） free electron laser （FEL）, with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation （HO） mode. In this paper, we investigate HO of HGHG FEL. Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy.
