Nonequilibrium effect for shot noise in ultrafast laser-induced electron emission

Summary form only given. Shot noise is the fluctuation in the electrical signal due to the discreteness of electron charges¹. The deviation of the uncorrelated shot noise is normally given by the Fano factor. Ultrafast electron pulse with high rightness and coherence can be generated by illumination of a dc-based metallic field emitter with femtosecond laser pulses². A nonequilibrium model based on Boltzmann´s equation has been used to explain the electron emission process³. Based on this model, the shot noise of the emission current is calculated. The effects of the shot noise reduction on applied dc voltage, laser intensity, pulse duration and metal work function are investigated. It is found that the Fano factor increases with small applied dc voltage, large laser field and longer time of tip and pulse interaction⁴. Our result would be helpful for investigate the coherence properties of ultrafast electron sources.