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型硅衬底的单尖硅场发射体（束流为200 nA，加速电压为25- 30 kV），在金属光栅上进行了场发射（550 nm间距），并成功地产生和探测了从紫外（300 nm）到红外（1400 nm）光谱范围内的Smith-Purcell辐射。我们还成功地利用直接电子通过间距为4160 nm的金属光栅，产生并探测了从紫外（400 nm）到红外（950 nm）的Smith-Purcell辐射（波长830 nm），并测量了p型Si场发射体的光响应特性。我们发现，调制光束（脉冲光束）产生直接从Si场发射器的脉冲激光束的照射。我们还发现光响应的上升时间足够快，但衰减时间约为30μsec，这是由耗尽层外产生的载流子寿命长而引起的扩散决定的（束流为50μA，加速电压为27.5kV），由热阴极发射，在金属光栅上进行了测量（60μm间距），成功地产生并探测了3 THz（0.1mm波长）和1.5THz（0.2mm波长）的Smith-Purcell辐射。

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).