Fig. 1. Comparison of the slippage at coming from harmonic generation and fundamental generation. The slippage in Fig.1 (a) is longer than that in Fig.1 (b)谐波辐射与基波辐射的滑移对比。对于辐射波长，其在图1(a)的滑移长度大于图1(b)

Fig. 2. Ratio of coherent lengths at a certain wavelength, for lasing at the third harmonic and at the fundamental wavelength

Fig. 3. Conceptual layout of the comparison of HLSS and SASE

Fig. 4. Comparison of the pulse energy and the bandwidth of FEL (10 shots average), from the third harmonic generation (THG) and from the resonant wavelength

Fig. 5. Variation of the energy and bandwidth (10 shots average) when scanning resonance wavelength in the HLSS scheme

Fig. 6. Comparison of HLSS and SASE (10 shots average) when lasing at 4.5 nm

Fig. 7. Comparison of the spectrum (10 shots average) at 6.75 nm from HLSS and SASE at different distance from the undulator exit