Gain characteristics of N₂ molecular dimer at 352.3 nm

Utilizing microwave discharge to excite the high pure nitrogen, and adopting the method of amplified spontaneous emission, the gain characteristics of N₂ molecular dimer at 352.3 nm is studied under different microwave exciting power and N₂ pressure. The law that little signal gain coefficients of N₂ molecular dimer at 352.3 nm change with microwave exciting power and N₂ pressure inside discharge tube, is given along the axis of discharge tube. The results indicate that the stimulated emission characteristics of N₂ molecular dimer at 352.3 nm exist, when the microwave power is greater than 100 W, and N₂ pressure in the range from 330 to 1800 Pa. When microwave power is 500 W N₂ pressure is 1100 Pa, the maximum little signal gain coefficient of N₂ molecular dimer at 352.3 nm is 1.08% cm^- along the axis of discharge tube. In addition, the gain distribution of N₂ molecular dimer at 352.3 nm along the radial direction of discharge tube is also given. The gain coefficient of N₂ molecular dimer at 352.3 nm is minimum at the centre of discharge tube, and maximum at the position close to the wall.