探讨了射频型远红外波导自由电子激光器(FIR—FEL)中产生超短光脉冲的可能性。由于短电子束辐射出与其长度相当的光脉冲.因此提出了选择适当的电子束起始相速度来确保正增益和光脉冲折射率沿相对滑移方向单调增加, 这样当光脉冲渡越折射率渐变的“增益介质”—电子束团时.光脉冲前后沿将向中心相向移动而使其径向宽度被压缩。则可能获得远红外波段的高功率超短光脉冲。

In this peper, we investigate the possibility of generating the ultrashort optical pulse in far-infrared free electron laser driven by a radio-frequency linear accelerator (RFLinac). The short electron pulse emits the optical pulse the length of which is correspondent with the length of the electron PUlse. We Present an equivalent refractivity to describe the Propegation of the optical pulse. When a moderate original Phase velocity of the electron pulse is chosen to ensure that the gum be POsitive and the equivalent refractivity monotonously increase along the relative slip distance, the leading and trailing edges will relativiely move toward the center of the optical pulse during interaction. Thus, the high-power and ultrashort optical pulse in the far-infrared region would be generated.