Power and efficiency enhancement of THz radiation in a plasma by dark hollow laser beams: Effects of magnetic field

Abstract The power and efficiency of terahertz radiation (THz) in a rippled density plasma by dark hollow laser beams are very small due to the collisional effect. We show that when a magnetic field is applied perpendicularly to the plasma, the THz radiation power and efficiency significantly enhance. Also, the magnetic field changes the THz radiation profile to a profile similar to a dark hollow laser beam. The mutual effect between the laser beams and THz radiation in plasma, which is important in high energy transfer between laser beams and THz radiation, is taken into account. We find that the maximum efficiency obtained in our scheme is more than four orders of magnitude greater than the efficiency in the absence of magnetic field.