Basic research of free electron laser using a micro-field emitter

1.采用纳米加工技术制备了n型和p型硅衬底的单尖端硅场发射体。我们将单端Si场发射极发射的直接电子束（电子束电流为200nA，加速电压为25-30kV）传递到金属光栅（550nm间距）上，成功地产生并检测了从紫外（300nm）到红外（1400nm）光谱范围内的Smith-Purcell辐射。我们也成功地产生和检测了史密斯-珀塞尔辐射光谱范围从紫外（400nm）到红外（950nm），通过直接传递电子金属光栅与4160nm的间距。将波长为830nm的GaAlAs激光器脉冲光照射在单端p型Si场发射体上，测量了p型Si场发射体的光响应特性。我们发现在脉冲激光束的照射下，硅场发射体直接产生了调制光束（脉冲光束）。我们还发现光响应的上升时间足够快，但衰减时间约为30μsec，这是由于耗尽层外产生的载流子寿命长导致的扩散所决定的。将热阴极发射的束流为50μA、加速电压为27.5kV的直接电子束照射到金属光栅（60μm间距）上，分别在3THz（波长0.1mm）和1.5THz（波长0.2mm）产生了Smith-Purcell辐射并进行了检测。

1.One tip Si field emitters using n-type and p-type Si substrates were fabricated by nano-machining technique.2.We passed a direct electron beam (the beam current of 200nA and the acceleration voltage of 25-30kV), which emitted from the one tip Si field emitter, on an metall grating (550nm pitch), and we successfully generated and detected the Smith-Purcell radiation in the spectral range from ultraviolet (300nm) to infrared (1400nm). We also successfully generated and detected the Smith-Purcell radiation in the spectral range from ultraviolet (400nm) to infrared (950nm) by passing a direct electron on a metal grating with a 4160nm pitch.3.We irradiated a pulse light emitted from a GaAlAs laser (the wavelength of 830nm) on a one tip p-type Si field emitter, and we measured photoresponse characteristics of p-type Si field emitter. We found that a modulated beam (pulse beam) was generated directly from the Si field emitter by the irradiation of the pulsed laser beam. We also found that the rising time of the photoresponse is enough fast, but the decay time is about 30μsec, which was determined by the diffusion due to the long life time of the carriers generated outside the depletion layer.4.We passed a direct electron beam (the beam current of 50μA and the acceleration voltage of 27.5kV), which emitted from a thermal cathode, on a metal grating (60μm pitch), and we suemssfully generated and detected the Smith-Purcell radiation at 3THz (the wavelength of 0.1mm) and 1.5THz (the wavelength of 0.2mm).