Terahertz Waves Generated Through Plasma Under Linear Electrodes

By placing a pair of linear electrodes at the focal point of a femtosecond laser, the plasma generated through the laser-ionized air is placed in the bias direct-current (DC) field generated by the linear electrode. We observe the tcrahcrtz characteristics of plasma in the bias-electric field in this case. By scanning the linear electrodes and observing the tcrahcrtz wave intensity, we obtain the optimal electrode position for enhancing the amplitude of tcrahcrtz wave. Results suggest that as the laser power increases, the optimal position moves in the direction of light propagation. This work not only studies the characteristics of tcrahcrtz signal generated through plasma under the modulation of linear electrodes, but also reveals the physical characteristics of plasma.