A compact terahertz CW HCN dual laser and its stability control

A compact terahertz continuous wave (CW) discharge-pumped Hydrogen cyanide (HCN) dual laser has been developed for better signal to noise ratio and higher time resolution, with active power and intermediate frequency (IF) control. The output power of about 1 similar to 10 mW on the 0.89 THz line has been obtained with 1 m long and 50 mm inner diameter dual discharge-pumped wave-guides laser. An output-power and IF feedback control system is applied to the HCN dual laser for output power and IF stability. This feedback system consists of two stepping motors, a piezoelectric ceramics (PZT), a PLC, a supervisory computer and the corresponding control program. The whole feedback control system can successful in stabilizing the power of the laser around 1-10 mW and the IF at around 1MHz in several hours.