| 摘要 |
An electron beam source (100) has a photocathode (110) with a photoemitter material (112) having a work function, and with a beam receiving portion (116) and an electron emitting portion (130) . A first light source (120) directs a first light beam (122) onto the beam receiving portion (116) of the photocathode (110) to generate an electron beam (103) from the electron emitting portion (130). The first light beam (122) has a wavelength lambda1 such that hclambda1 is at least about the work function of the photoemitter material (112), where `h' is Planck's constant and `c' is the speed of light. A second light source (120) directs a second light beam (103) onto the beam receiving portion (116) of the photocathode (110), such as onto the beam receiving portion (116), to stabilize the electron beam (103). The second light beam (122) having a wavelength lambda2 such that he/lambda2 is less than about the work function of the photoemitter material (112). |
