[1] J M J Madey. Stimulated emission of Bremsstrahlung in a periodic magnetic field[J]. J Appl Phys, 1971, 42(5): 1906-1913.
[2] A M Kondratenko, E L Saldin. Generation of coherent radiation by a relativistic electron beam in an ondulator[J].Particle Accelerators, 1980, 10: 207-216.
[3] R Bonifacio, C Pellegrini, L M Narducci, Collective instabilitics and high- gain regime in a free electron laser[J]. Opt Commun, 1984, 50(6): 373-378.
[4] T G Orzechowski, B Anderson, W M Fawley, et al.. Microwave radiation from a high-gain free electron laser amplifier[J]. Phys Rev Lett, 1985, 54(9): 373-378.
[5] M Hogan, C Pellegrini, J Rosenzweig, et al.. Measurement of high gain and intensity fluctuations ina self- amplified spontaneous-emission free-electron laser[J]. Phys Rev Lett, 1998, 80(2): 289-292.
[6] L H Yu. Generation of intense UV radiation by subharmonically seeded single-pass free-electron laser[J]. Phys Rev A,1991, 44(8): 5178-5193.
[7] L H Yu, M Bazien, I Ben- Zvi, et al.. High- gain harmonic generation free- electron laser[J]. Science, 2000, 289(5481):932-934.
[8] P Emma, R Akre, J Arthur, et al.. First lasing and operation of Anngstrom wavelength free- electron laser[J]. Nature Photonics, 2010, 4(9): 641-647.
[9] T Ishikawa, H Aoyagi, T Asaka, et al.. A compact X- ray free- electron laser emitting in the subangstrom region[J].Nature Photonics, 2012, 6(8): 540-544.
[10] Z T Zhao. Seeding experiments at the SDUV-FEL[R]. FEL 2011, WEOBI2 (invited talk), 2011.
[11] B Liu, W B Li, J H Chen, et al.. Demonstration of a widely- tunable and fully- coherent highgain harmonic- generetion free-electron laser[J]. Phys Rev ST Accel Beams, 2013, 16(2): 699-704.
[12] L H Yu, I Ben- Zvi. High gain harmonic generation of soft X- rays with the“fresh bunch”technique[J]. Nucl Instrum Methods Phys Res A, 1997, 393(1-3): 96-99.
[13] Juhao Wu, Lihua Yu. Coherent hard X- rays production by cascading stages of high gain harmonic generation[J]. Nucl Instrum Methods Phys Res A, 2001, 475(1-3): 104-111.
[14] S Di Mitri, E Allaria, D Castronovo, et al.. Double stage seeded FEL with fresh bunch injection technique at FERMI@Elettra[C]. Proc IPAC 2013, 2013. TUPEA011.
[15] L Giannessi. FERMI demonstrates first seeded free electron laser working in double- stage cascaded configuration[J].Synchrotron Radiation News, 2013, 26(1): 48.
[16] H K Avetissian, G F Mkrtchian, Nonlinear quantum regime of the X- ray Compton laser[J]. Phys Rev, 2002, 65(4Pt2B):046505.
[17] R H Pantell, G Soncini, H E Puthoff. S-9—Stimulated photon-electron scattering[J]. IEEE J Quant Electron, 1968, QE-4(11): 905-907.
[18] Wang Qingyuan, Yu Shanfu, Liu Shenggang. Exact sinhle particle theory of free electron laser and its applications[J].High Power Laser and Particle Beams, 1991, 3(1): 23-31.
[19] Liu Shenggang. Space- charge wave theory of free electron laser[J]. High Power Laser and Particle Beams, 1990, 2(2):131-147.
[20] Liu Shenggang. Linear theory of free electron laser[J]. J UEST of China, 1990, 19(1): 1-8.
[21] Xie Jialin. Electron- photon interactions and the developments of free electron lasers[J]. J Graduate School of the Chinese Academy of Sciences, 2002, 19 (1): 7-17.