Optics and Photonics Society of Iran

The electromagnetic pulses in the terahertz spectral range (0.1-30 THz) have numerous applications in spectroscopy, biology and medicine, T-ray imaging and information technology. Therefore, in this paper, the THz generation due to the interaction of a femtosecond laser pulse and its second harmonic with a background gas is studied. In addition, the effects of the laser pulse initial phase, phase difference of the laser pulse and its second harmonic, the background gas type and its pressure on the generated THz field are investigated. The results show that the THz generation efficiency is increased with the increment of the background gas pressure and the decrement of its ionization potential. Moreover, increment of the pulse initial phase, and also the phase difference lead to the same result.