Pair Production in an Intense Laser Pulse: The Effect of Pulse Length
REN Na1, WANG Jia-Xiang1, LI An-Kang1, WANG Ping-Xiao2
1State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 2Key Laboratory of Applied Ion Beam Physics Laboratory (Ministry of Education) and Institute of Modern Physics, Department of Nuclear Science and Technology, Fudan University, Shanghai 200433
Pair Production in an Intense Laser Pulse: The Effect of Pulse Length
REN Na1, WANG Jia-Xiang1, LI An-Kang1, WANG Ping-Xiao2
1State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 2Key Laboratory of Applied Ion Beam Physics Laboratory (Ministry of Education) and Institute of Modern Physics, Department of Nuclear Science and Technology, Fudan University, Shanghai 200433
Production of positron-electron (e+e−) pairs in an intense laser pulse is investigated by solving the Dirac equation with analytical and numerical methods. We observe that the probability of the pair production will firstly decrease slowly as the pulse length τ becomes shortened. Then it will increase until τ is reduced to the Compton time τc=?/(mec)≈1.29×10−21 s and finally decrease exponentially to zero. Hence, for a prominent pair production, we not only require that the electric field strength should be higher than the the Schwinger critical value Ecr=m2c3/(e?)≈1.32×1016 V/cm, but also that the pulse duration τ should be larger than τc. The latter is shown to be related to momentum requirement for the transition. For fields with different pulse lengths, the phase and chirp influences upon the pair production are also explored.
Production of positron-electron (e+e−) pairs in an intense laser pulse is investigated by solving the Dirac equation with analytical and numerical methods. We observe that the probability of the pair production will firstly decrease slowly as the pulse length τ becomes shortened. Then it will increase until τ is reduced to the Compton time τc=ħ/(mec)≈1.29×10−21 s and finally decrease exponentially to zero. Hence, for a prominent pair production, we not only require that the electric field strength should be higher than the the Schwinger critical value Ecr=m2c3/(eħ)≈1.32×1016 V/cm, but also that the pulse duration τ should be larger than τc. The latter is shown to be related to momentum requirement for the transition. For fields with different pulse lengths, the phase and chirp influences upon the pair production are also explored.
REN Na, WANG Jia-Xiang, LI An-Kang, WANG Ping-Xiao. Pair Production in an Intense Laser Pulse: The Effect of Pulse Length[J]. 中国物理快报, 2012, 29(7): 71201-071201.
REN Na, WANG Jia-Xiang, LI An-Kang, WANG Ping-Xiao. Pair Production in an Intense Laser Pulse: The Effect of Pulse Length. Chin. Phys. Lett., 2012, 29(7): 71201-071201.
2012, Vol. 29 
